Zuku: Anesthesia – Flashcards
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Which of the following is the most correct description of multi-modal analgesia? (A) Combination of different types of analgesic medications and procedures to treat pain (B) Treatment with pain medication during surgery and prior to recovery of a patient (C) Administration of pain medication prior to elective surgery and stimulation of the pain response (D) Use of an antagonist to reverse dangerous side effects of an analgesic medication (E) Use of higher doses of pain medication given previously to a patient to achieve adequate analgesia
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Answer is A: Multi-modal analgesia is the simultaneous use of multiple classes of analgesic drugs and/or techniques to treat pain. It is also called balanced analgesia. Targeting different parts of the pain pathway at the same time, and combining drugs to utilize synergistic and/or additive effects results in better analgesia. It also allows the use of lower doses (including inhalants), and minimizes side effects as well as cost. Complications may be less frequent, hospital stays are shorter, bills are lower, and patients are more comfortable. Many, many possible combinations exist. Example: A non-steroidal anti-inflammatory analgesic (carprofen) is given prior to premedication or before recovery. Then, an opioid (morphine, fentanyl, etc) is combined with sedatives (acepromazine, dexmedetomidine, etc.) for premedication, and continued during maintenance and recovery. Local anesthesia is used whenever possible via a nerve block, infiltration, epidural, or infusion. Infusions of an opioid with lidocaine and/or ketamine are given during maintenance and recovery. Click here to see a good summary on pain management, courtesy of the American College of Veterinary Surgeons (ACVS).
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Salivation stops in most animals under inhalant general anesthesia. Which one of the following animals CONTINUES to salivate regardless of the drugs used? (A) Feline (B) Canine (C) Bovine (D) Equine
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Answer is C: Ruminants and camelids continue to salivate under sedation or anesthesia, even when anti-cholinergics are given. This is why it is important to intubate ruminants and camelids during inhalent anesthesia and to position the nose down so that the saliva can drain away from the pharynx. These species also regurgitate rumen fluid under anesthesia, especially during light or deep anesthesia, so be aware of this possibility. Regurgitation can be active or passive; it is active whenthey are light and esophageal contractions occur. It is generally passive when they are very relaxed and adequately anesthetized. For more, see Anesthetic Monitoring by Lyon Lee DVM, PhD.A
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To what should the anesthetic dial be set to help most patients reach a surgical plane of anesthesia with most anesthetic agents? (MAC = minimum alveolar concentration) (A) 2.0 x MAC (B) 3.0 x MAC (C) Equal to MAC (D) There is no standard setting (E) 1.5 x MAC
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Answer is E: For most anesthetics and most patients, a dial setting of 1.5 x MAC is utilized to reach a surgical plane of anesthesia. The minimum alveolar concentration (MAC) of an anesthetic agent is the percent concentration at which 50% of patients would not respond to surgical stimulation.
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What is the purpose of a canister of soda lime granules in an anesthetic circuit? (A) Absorb carbon dioxide (B) Filter hydroxyl groups from injected opiods (C) Deactivate anesthetic gasses (D) Balance alkalosis and acidosis (E) Supplement moisture
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Answer is A: The purpose of a canister of soda lime granules is to absorb carbon dioxide from exhaled anesthetic gasses. Fresh absorbent crystals are white and can be crushed. But exhausted, saturated crystals become a distinct off-white color and are hard. Most granules contain a pH-sensitive dye that becomes visible as the absorbent granules become saturated. (The color itself is not so important as the color changing). A color change from white to purple or violet typically indicates that the CO2 scavenger granules have become saturated with CO2, but this color change does not always happen, and will dissipate after a few hours.
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Which of the following drugs used for anesthesia should ONLY be given intravenously through a patent intravenous catheter? (A) Propofol, alfaxalone (B) Guaifenesin, thiopental (C) Dexmedetomidine, butorphanol (D) Ketamine, diazepam
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Answer is B: Guaifenesin (GG)and thiopental are both very caustic to tissues if they are accidentally injected perivascularly-they should only be given through a patent intravenous catheter. A catheter is also necessary to accommodate the high volumes required in large animals, generally 500-1000 ml of a 5% solution of GG, 40-60 ml of a 5% solution of thiopental. Thiopental is a very short acting barbiturate used for induction of anesthesia in many animals. It has a very high pH, 10-11, so it is very alkaline, similar to bleach and sodium hydroxide. Guaifenesin is a centrally acting muscle relaxant that is used in large animals with thiopental or ketamine for induction of general anesthesia. It is also called glycerol guaicolate, or GG. Concentrations of GG above 7% cause hemolysis in cattle and 10% GG solutions cause phlebitis in horses, so a 5% solution is now the standard.
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Which of the following patients is most likely to develop central sensitization of the pain response? (A) Every 30 seconds (B) Every 10-15 minutes (C) Every 3-5 minutes (D) Every 7-10 minutes (E) Every 1-2 minutes
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Answer is C: After induction, propofol boluses should be given every 3-5 minutes or a constant rate infusion should be used. Propofol is an ultra-short-acting IV anesthetic that can be used to induce and/or maintain general anesthesia in many veterinary species. Animals typically sit up within 10 minutes and stand within 15-30 minutes of cessation of propofol.
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A surgical repair of a patent ductus arteriosus was performed via thoracotomy in a 4 month old Labrador puppy. In recovery, the puppy is found in his cage, crying and whining. His breaths are short and fast. When a technician attempts to comfort him, he tries to get away, cowers in the corner, and cries louder. Which of the following is the best explanation of this scenario? (A) This puppy is painful, pain management is inadequate (B) This is the clinical picture of opioid dysphoria (C) Recovery is prolonged, stage II signs are still occurring (D) Labradors often do this in recovery, they have low pain tolerance
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Answer is A: This puppy is painful, pain management is inadequate, as these are signs of pain. Behavioral changes are the most reliable signs of pain in animals. Tolerance levels and socialization skills certainly vary in all species, however, signs of pain should be anticipated, repeatedly evaluated, and treated in all cases. A thoracotomy is one of the most painful procedures performed in animals and humans. Intense pain management is required, including: 1)an opioid in combination with a tranquilizer or sedative, 2) a non-steroidal anti-inflammatory agent, and 3) intercostal and intrapleural nerve blocks with a long acting local anesthetic, e.g. bupivacaine. Continuous infusion of lidocaine, ketamine, and/or an opioid such as fentanyl or morphine provides excellent analgesia and some sedation. This can replace # 1 above. Shallow respiration is common in patients with chest pain; hypoventilation and hypoxemia can result. Opioids can depress respiratory function, but adequate pain management will improve ventilation when it doesn't hurt so much to breathe. Although labrador puppies are generally most gregarious and responsive to people, they still exhibit signs of pain when present. Sometimes we need to look very closely; don't believe that wagging tail!
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Pentobarbital is the principal active ingredient in euthanasia solutions. How does pentobarbital cause death? (A) Severe, rapid drop in blood pressure (B) Oxygen depletion (C) Cardiac arrest (D) Respiratory depression
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Answer is D: Pentobarbital, like all barbiturates, is associated most with respiratory depression. When you give barbiturates to induce anesthesia (think methohexital, thiopental) you give them SLOWLY to avoid respiratory depression, and you keep respiratory assistance (oxygen) on hand. If you give a euthanasia-dose of pentobarb fast IV, the animal stops breathing and simply collapses. For cardiac arrest, think more of potassium. Technically, you could argue that oxygen depletion is the cause of death by pentobarb, but it is the respiratory depression that gets you there. Remember CATS are particularly sensitive to respiratory depression from barbiturates.
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Which of the following opioids is more potent than morphine, given most often via continuous intravenous infusion and can be administered via transdermal patch? (A) Tramadol (B) Oxymorphone (C) Buprenorphine (D) Fentanyl
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Answer is D: Fentanyl is very lipophilic, so it is absorbed and eliminated quickly. It is therefore not useful for pain control via single doses given intramuscularly (IM) or intravenously (IV). However, it produces good analgesia when given continuously via intravenous infusion and, in many patients, via a transdermal patch. Serum levels can be variable in some patients with patches. Absorption is affected by temperature; the use of heating blankets can increase levels, hypothermia will decrease levels. Fentanyl is less likely to cause nausea and vomiting compared to morphine and other mu-agonist opioids. It does cause respiratory depression and dysphoria in some patients. Other analgesics that can be administered via transdermal patches are lidocaine and buprenorphine. Use of patches in patients at home must be evaluated carefully - toxicity and death has been seen in children and small animals that have ingested fentanyl patches.
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When used as a preanesthetic, atropine will: (A) Stimulate excessive salivary secretion (B) Provide sufficient anesthesia for minor surgery (C) Cause the pupils to dilate (D) Frequently produce vomiting
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Answer is C: At moderate doses Atropine dilates pupils, and increase heart rate. High doses will decrease GI and urinary tract motility. A very high dose will inhibit gastric secretion.
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Thiopental is not an appropriate choice for anesthetic induction in sighthounds (e.g., Greyhounds). Why? (A) Rapid urinary excretion, high risk of perivascular irritation if injection error (B) Thiopental is highly protein-bound, these breeds have decreased albumin (C) Causes significant respiratory excitement, cost-prohibitive in large-breed dogs (D) May cause seizures due to altered blood-brain-barrier in these dogs (E) Greyhounds have low body fat, inefficient liver metabolism
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Answer is E: The low body fat and less efficient liver metabolism in sighthounds make thiopental a poor choice for use in these breeds. Anesthesia and recovery times are much longer than in other breeds. Thiopental is very lipophilic - meaning a lot is absorbed into adipose tissue. When there is minimal adipose tissue (such as in sighthounds), blood levels remain higher longer. Check out a graphic image of redistribution of thiopental from OK State (note that the level of drug in fat is still increasing while it is decreasing in other tissues). Merck provides a good review on pharmacokinetics. Thiopental can cause heart arrhythmias (usually ventricular bigeminy) and temporary apnea after injection. It must be given via an IV catheter as perivascular injection will cause tissue necrosis due to its very high pH of 12. AAHA has an excellent online article on Anesthesia Guidelines for Dogs and Cats.
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Which of the following choices are best for treating a patient that survives cardiac arrest but continues to have a persistent and unstable ventricular tachycardia? (A) Lidocaine or mexilitine (B) Calcium gluconate or sodium bicarbonate (C) Amiodarone or magnesium sulfate (D) 5% Dextrose or hypertonic saline solution
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Answer is C: Amiodarone or magnesium sulfate are preferred for treatment of persistent ventricular tachycardia following cardiac arrest. Lidocaine is sometimes used, however, amiodarone is associated with better outcomes. Mexilitine is an oral medication that is not used in these patients. It is used in dogs with ventricular arrhythmias caused by cardiomyopathy. Download this free issue of the Journal of Vet Emergency and Critical Care with CPCR guidelines for animals
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The minimum alveolar concentration (MAC) is the lowest concentration of anesthetic in alveolar gas that prevents physical response in what percentage of animals exposed to a surgical stimulus? (A) 50 (B) 25 (C) 75 (D) 95
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Answer is A: 50% of animals exposed to a surgical stimulus will respond when maintained at the MAC, or the minimum alveolar concentration for that inhalant anesthetic. With sedatives and analgesics in addition to the inhalant, most patients can be maintained at 1 -1.5 MAC during general anesthesia. MAC enables comparison between inhalants and provides another monitoring variable for the anesthetist. Inhalants with high potency (need less drug) have a lower MAC. These are also more soluble in blood and tissues, e.g. Halothane is more soluble, MAC is 0.88; Desflurane is not, MAC is 7-9 in most animals. The requirement (%) for less soluble drugs is greater, but induction is much faster. Anesthesia occurs only when the concentration of inhalant in the blood and alveoli are equal. Less soluble drugs achieve this equilibrium faster. Since there is also less drug in the tissues, recovery is also faster compared to more soluble drugs. When the vaporizer is turned off, alveolar levels drop rapidly, followed by blood and tissue levels. Click these links for more info on inhalants from Hope Hospital in the UK by A. Mason and Oklahoma State Anesthesiology notes by Lyon Lee DVM, PhD.
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Which of the following is the correct explanation of multi-modal analgesia? (A) Combination of different classes of analgesic medications and procedures to treat pain (B) Treatment with pain medication during surgery and prior to recovery of a patient (C) Administration of pain medication prior to elective surgery and stimulation of the pain response (D) Use of an antagonist to reverse dangerous side effects of an analgesic medication
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Answer is A: Multi-modal analgesia is the simultaneous use of multiple classes of analgesic drugs and/or techniques to treat pain. It is also called balanced analgesia. Targeting different parts of the pain pathway at the same time, and combining drugs to utilize synergistic and/or additive effects results in better analgesia. It also allows the use of lower doses (including inhalants), and minimizes side effects as well as cost. Complications may be less frequent, hospital stays are shorter, bills are lower, and patients are more comfortable. Many, many possible combinations exist: Example: A non-steroidal anti-inflammatory analgesic(carprofen) is given prior to premedication or before recovery; an opioid (morphine, fentanyl, etc) is combined with sedatives (acepromazine, dexmedetomidine, etc.) for premedication, and continued during maintenance and recovery. Local anesthesia is used whenever possible via a nerve block, infiltration, epidural, or infusion. Infusions of an opioid with lidocaine and/or ketamine are given during maintenance and recovery
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Which of the following clinical signs are most consistent with Stage 3, plane III of general anesthesia in dogs and cats? (A) Abnormal nystagmus, brisk corneal response, pupils miotic (B) Eyes roll dorsally, weak palpebral response, pupils variable (C) Eyes central, dilated pupils, strong palpebral response (D) Eyes ventral, no palpebral response, pupils dilated
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Answer is D: Stage 3, plane III is deep general anesthesia (GA) in dogs and cats -the eyes roll ventrally, pupils are dilated and there is no palpebral response. Some practitioners describe Stage 3, plane III as "early overdose". Stage 3, plane II medium GA is preferred for most invasive surgical procedures. The eyes of cattle also roll ventrally and have no palpebral response at Stage 3, plane III. There is variability between patients, protocols and procedures, and some authors differ when describing differences between stages of GA. For example, dilation of the pupil is affected by depth but also by adjunct drugs such as anti-cholinergics (atropine, etc) and paralytic agents (atracurium).
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Why should reptiles be kept at the upper limit of their normal temperature range during induction, surgery and anesthetic recovery? (A) Prevents vomiting (B) Optimizes anesthetic metabolism and recovery (C) Lower temperatures associated with paradoxic tachycardia (D) Delays righting reflex until animal is fully awake (E) Prevents switching to anaerobic metabolism
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Answer is B: Reptiles have a preferred optimal temperature range (POTR) for optimal uptake, action, transformation and excretion of premedication sedatives and maintenance anesthetics. Lower temperatures slow a reptile's metabolism which, in turn slows the elimination of drugs out of the body and delays recovery from anesthesia or sedation
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Which anesthetic drug commonly causes vomiting in cats? (A) Xylazine (B) Ketamine (C) Propofol (D) Thiopental
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Answer is A: Xylazine can cause vomiting and retching as well as muscle tremor, bradycardia and reduced respiratory rate in cats. Thiopental and propofol can cause apnea (stopped breathing) after injection. Remember to protect a cat's eyes with ophthalmic ointment when using ketamine, because they remain open after injection.
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During surgery in a dog anesthetized for enucleation of the left eye, the heart rate slows down every time the surgeon manipulates the globe. What following is the correct name for this response? (A) Vago-vagal response (B) A Valsalva maneuver (C) Oculo-cardiac reflex (D) The baroreceptor response
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Answer is C: The oculo-cardiac reflex (OCR) is slowing of the heart rate when intraocular pressure (IOP) increases. This may occur when the globe is manipulated during any eye surgery, but is more common during an enucleation. Direct pressure on the globe or traction on the extraocular muscles stimulates the trigeminal nerve, which relays this input to the brain. Vagal centers are stimulated which send impulses to the heart, causing bradycardia and occasionally even cardiac arrest. Stimulation of the OCR by applying pressure to the eyeball(s) is also a treatment for supraventricular tachycardia in awake patients.
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What is the maximum dose of bupivacaine 0.5% that is safe to give a dog during dental surgery? (A) 3 mg/kg (B) 1.5 mg/kg (C) 2 mg/kg (D) 1 mg/kg (E) 0.5 mg/kg
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Answer is C: The maximum dose of bupivacaine that is considered safe in dogs is 2 mg/kg; in cats, it is 1.5 mg/kg. Therefore, the total volume of bupivacaine needed during the procedure should be divided between the quadrants that are going to be blocked.
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A healthy, one year old cat is castrated under anesthesia with dexmedetomidine, butorphanol, and ketamine. A dose of meloxicam and buprenorphine are given for post-operative analgesia, and he is placed in recovery after 45 minutes. One hour following surgery, the cat is found in his cage lying quietly in sternal recumbency. He rouses a bit when stimulated, but remains quiet if left alone. His heart rate is 140, mucous membranes are pink, capillary refill time is 1-2 seconds. Which of the following is the best interpretation of this scenario? (A) Hypothermia may be prolonging recovery (B) Internal bleeding must be present, causing somnolence (C) The cat is not yet completely awake, so an accurate assessment is not possible (D) Hypotension has slowed elimination of the anesthetic drugs (E) Everything is fine, this cat is comfortable, good pain management
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Answer is E: Everything is fine, this cat is comfortable; good pain management is present for a mild to moderately painful procedure. The usual doses of dexmedetomidine, butorphanol, and ketamine used in a healthy cat provide about an hour of anesthesia for minor surgical procedures such as a castration. Complete recovery takes approximately 2-3 hours (from administration) with this combination. When good pain management is present, patients will rest quietly, sleep readily, and behave normally during interaction with caretakers. Changes in behavior are more indicative of pain than are physiologic variable such as heart rate, blood pressure, etc.
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Which drug is the most fat soluble and might have delayed elimination/excretion in an obese dog or cat? (A) Acepromazine (B) Thiopental (C) Xylazine (D) Ketamine
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Answer is B: Thiopental is an ultra-short-acting barbiturate that can be stored in fat and slowly released. Usually use thiopental to INDUCE anesthesia (IV injection). 3 things to remember about barbiturates: 1. Really fat animals & sighthounds (like greyhounds, afghans) have trouble excreting barbiturates. Methohexital is a better choice for both. 2. Beware of RESPIRATORY DEPRESSION with barbiturates. 3. Two other barbiturates often used are PENTObarb (in euthanasia solutions) and PHENObarb (used to control epilepsy/seizures)
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In which animal do you typically AVOID using Atropine (anti-cholinergic) as a premedication before inducing anesthesia? (A) Horse (B) Pig (C) Cat (D) Dog
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Answer is A: Atropine slows the gut, so there is concern that they might cause colic in HORSES. This is less likely with another anti-cholinergic, glycopyrrolate, so it is sometimes used to prevent bradycardia (slow heart rate) in anesthetized horses
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Which drug is best for fast anesthetic induction in a greyhound? (A) Methohexital (B) Phenobarbital (C) Pentobarbital (D) Thiopental
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Answer is A: Really fat animals and sighthounds (like greyhounds, afghans) have trouble excreting barbiturates like the 4 choices here. Methohexital is a better choice for both because it does not absorb into fat and quickly induces anesthesia. (McCurnin & Bassert note alternatively could use propofol in sight hounds). Beware of RESPIRATORY DEPRESSION with barbiturates. Thiopental is an ultra-short-acting barbiturate that CAN be stored in fat and slowly released. Think of euthanasia with PENTObarb. Think of PHENObarb to control epilepsy/seizures.
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How often should healthy small animal patients be given a breath via periodic ventilation during general anesthesia? (A) Every 1-2 minutes (B) It is unnecessary if they are healthy (C) Every 5-7 minutes (D) Every 8-10 minutes (E) Every 2-5 minutes
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Answer is E: Periodic ventilation every 2-5 minutes is used to prevent atelectasis in healthy patients. It is also used for hypoventilating or apneic patients.
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Of the following large animals, which one is the most sensitive to the sedative effects of xylazine? (A) Equine (B) Bovine (C) Swine (D) Swine Alpaca (E) Llama
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Answer is B: Ruminants are the large animals most sensitive to the sedative effects of xylazine, followed by camelids, equine, and then swine. Cattle require approximately 1/10th the dose of xylazine used in horses. Lower doses produce sedation without recumbency; higher doses produce profound sedation and recumbency. Some cattle breeds (Brahma, Hereford) require lower doses than others (Holstein). Alpacas usually require a bit higher dose than llamas. The addition of an opioid such as butorphanol provides profound sedation and analgesia and allows the use of lower doses of xylazine. Since ruminants and camelids regurgitate normally when awake, this can occur passively when sedated. The head and neck should be positioned such that aspiration is avoided while recumbent. Tracheal intubation is recommended whenever possible especially for long procedures. The effects of the alpha-2 agonists can be reversed with yohimbine, tolazoline, or atipamezole. Equine and camelids are quite sensitive to tolazoline. Swine respond poorly to xylazine when used alone, and often still vocalize and respond to manipulation even when ketamine is added. Use of the more potent alpha-2, medetomidine, combined with a benzodiazepine and an opioid, (eg., midazolam and butorphanol, respectively) improves sedation dramatically in swine.
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Propofol is a non-barbiturate agent used to induce anesthesia. Which statement is most correct about propofol? (A) Propofol is slowly cleared from the body (B) Highly irritating if accidentally injected peri-vascular (C) Do not mix propofol with thiopental (D) Discard unused propofol after 6 hours
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Answer is D: Opened vials of propofol should be discarded after 6 hours or they may support bacterial growth. You CAN mix 1%propofol with 2.5% thiopental as an induction agent. Propofol is RAPIDLY cleared, and is NOT particularly irritating to tissues if it goes outside the vein accidentally. (UNlike thiopental, which is VERY irritating if it goes peri-vascular)
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Ultra-short acting barbiturates can cause severe tissue irritation and sloughing if they accidentally get outside the vein when injected. Beware of RESPIRATORY DEPRESSION with barbiturates. (A) Cardiac arrest (B) Slough tissues (C) Nothing (D) Seizures
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Answer is B: Ultra-short acting barbiturates can cause severe tissue irritation and sloughing if they accidentally get outside the vein when injected. Beware of RESPIRATORY DEPRESSION with barbiturates.
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Which drug is often used to control epilepsy (idiopathic seizures), when common metabolic and toxic causes have been ruled out? (A) Pentobarbital (B) Thiopental (C) Methohexital (D) Phenobarbital
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Answer is D: These drugs are all barbiturates. Think of PHENObarb to control epilepsy/seizures. Can see agitation/excitement at first, or profound depression, so need to monitor. Methohexital and thiopental are ultra-short-acting barbiturates used to induce anestheasia. Pentobarbital used primarily as a euthanasia agent today.
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Salivation stops in most animals under inhalant general anesthesia. Which one of the following animals CONTINUES to salivate regardless of the drugs used? (A) Feline (B) Bovine (C) Equine (D) Canine
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Answer is B: Ruminants and camelids continue to salivate under sedation or anesthesia, even when anti-cholinergics are given. This is why it is important to intubate ruminants and camelids during inhalent anesthesia and to position the nose down so that the saliva can drain away from the pharynx. These species also regurgitate rumen fluid under anesthesia, especially during light or deep anesthesia, so be aware of this possibility. Regurgitation can be active or passive; it is active whenthey are light and esophageal contractions occur. It is generally passive when they are very relaxed and adequately anesthetized.
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Which one of the following choices best explains the concept of balanced anesthesia? (A) Use of two or more drugs to achieve the desired level of anesthesia (B) Maintaining the same ratio of anesthetic gas to oxygen used (C) Varying the dose of the anesthetic used to maintain a certain depth (D) Matching the dose of anesthetic drug used to the body weight of patient
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Answer is A: Balanced anesthesia is the use of two or more drugs to achieve the desired level of anesthesia.
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What is the function of an anesthetic vaporizer? (A) Controls the fresh gas flow rate into breathing circuit (B) Vaporizes liquid inhalant anesthetics (C) Moisturizes inhaled gases (D) Scavenges CO2 vapor from exhaled gases
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Answer is B: Vaporizers convert volatile liquid anesthetics (like isoflurane) into vapor that is combined with a carrier gas for delivery into the patient's breathing circuit. 100% oxygen is used most commonly in veterinary medicine but oxygen can also be combined with air or nitrous oxide. There are many ways to categorize vaporizers, three are described below: 1. Carrier gas flow - variable bypass or measured flow 2. Method of vaporization - flow over, bubble through, and injection 3. Accuracy - Precison or non-precision. Precision vaporizers deliver precise a concentration of inhalant anesthetic regardless of gas flow rate, temperature, or ventilation, and are typically positioned OUTSIDE the breathing circuit. Non-precision vaporizers do NOT deliver a precise concentration of anesthetic, are affected by changes in the gas flow rate, temperature, and ventilation, and are usually positioned INSIDE the breathing circuit.
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In which animal would it be best to use glycopyrrolate as an anesthetic pre-medication, rather than Atropine? (A) Pregnant animals (B) Obese animals (C) Pigs (D) Diabetics
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Answer is D: Glycopyrrolate crosses the placenta only marginally, so it is a better choice for pregnant animals (unlike atropine, which crosses more easily). This situation is likely to arise if you are doing a cesarean section. Anti-cholinergics like Atropine or Glycopyrrolate, are given as pre-meds to INCREASE heart rate, DECREASE salivation and DECREASE airway secretions. Remember that many anesthetic drugs (like opiates, barbiturates, gas anesthetics) promote bradycardia (slowed heart rate) and some dissociative anesthetics (like ketamine, tiletamine) cause excessive salivation.
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Which of the following most correctly describes physiologic pain? (A) Pain that originates from damage to peripheral nerves or the central nervous system (B) Pain that results when homeostasis is disturbed, as when disease is present (C) The sensation that results when nociceptors are activated (D) A protective response to an actual or potentially damaging insult
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Answer is D: Physiologic pain is a protective response to an actual or potentially damaging insult. It provides a mechanism whereby the subject may avoid or minimize injury from both internal and external sources. Physiologic pain is also called nociceptive pain, as it involves the basic mechanisms of reception, transmission, and processing of pain stimuli that leads to perception of pain. This physiologic process is called nociception. Response to physiologic pain is behavorial, emotional, and physiologic, and both involuntary and voluntary. The classic example - when one's hand touches something hot, you unconsciously withdraw your hand and your heart rate increases, etc. The withdrawal and tachycardia are involuntary responses that occur almost immediately. The next event is behavioral and voluntary, where you move away, get an insulated glove, or somehow change how you handle the hot item, etc. The emotional component is when you exclaim OUCH. See the Taxonomy of pain from the IASP, and How to Pinpoint Pain in small animals from the Am. Animal Hospital Assoc.
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A cardiac arrhythmia is ausculted during a preoperative examination in a 3 year old thoroughbred gelding. The heart rate is 32 beats/minute [N=28-42] and the rhythm is regularly irregular. Click to see an image of this electrocardiogram. Which of the following correctly identifies this rhythm? (A) Atrial fibrillation (B) 2nd degree AV block (C) Sinus arrest (D) Idiopathic bradycardia
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Answer is B: Conduction of the normal depolarization wave stops at the AV node, usually because it has taken too long to arrive and the node is refractory, unable to depolarize at that time. 2nd degree° AV block is more common in horses at rest, when the heart rate is low, as it is associated with increased vagal (parasympathetic) tone. When sympathetic tone increases, as with exercise, excitement, pain, etc., the heart rate increases and AV block disappears. 2nd degree block can be diagnosed without an ECG. The rhythm is regularly irregular, the pause is equal to 2X the normal interval between contractions, the 4th heart sound (S4) is audible during the pause, and the irregularity disappears when the HR increases. Click this link to see this ECG with legend. Click this link for excellent website - Interpretation of ECGs from UPenn.
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Which of the following most correctly describes the conduction pathway of the depolarization wave in the heart? (A) R ventricular myocardium -purkinje fibers -AV node -atria (B) R atrial appendage -RA node -purkinje fibers -ventricles (C) SA node - AV node - Bundle of His - purkinje fibers - ventricles (D) L atrial myocardial tissue -SA node -AV node -ventricular myocardium
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Answer is C: SA node - AV node - Bundle of His - purkinje fibers - ventricles. The cardiac pacemaker cells located in the SA node generate an action potential that spreads into the atrial myocardium and follows internodal conduction pathways to the AV node. Here the speed of conduction slows to allow the entire atria to contract. It then goes through the Bundle of His to the bundle branches which lead to the Purkinje fibers in the ventricular myocardium. Cardiac arrhythmias can originate in the myocardium or in the conduction system. The latter are most often known as 'blocks', for example -first, second, and third degree atrioventricular block, sinus block or arrest, bundle branch blocks, etc.
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A cat undergoes an exploratory laparotomy for a linear foreign body. At surgery, a 10 inch long boot lace is removed from the small intestine via 3 different enterotomies. In recovery, she is found hunched up in the back of the cage. She is not asleep, but she is very quiet, and does not respond or hiss during interaction with the recovery technician. Which of the following is the best explanation of this scenario? (A) Hypothermia after anesthesia is common and is likely prolonging recovery (B) The cat probably isn't quite awake yet (C) Blood loss during the surgery may have resulted in obtundation (D) This cat is painful, pain control is inadequate
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Answer is D: This cat is painful, inadequate pain management is present- Reluctance to move, sitting hunched up, and lack of response or a negative response to interaction are signs of pain in cats. Changes in behavior are more indicative of pain in animals than are physiologic variables such as heart rate, blood pressure, etc. When good pain management is present, patients will rest quietly following anesthesia, behave fairly normally - they are able to sleep, will eat, drink, and groom themselves, and respond positively during interaction with caretakers. Individual variation in pain tolerance and socialization skills is seen in all species, but signs of pain should be anticipated, repeatedly evaluated, and treated in all cases. Cats are more difficult to evaluate than dogs, we must look closely, quiet does not necessarily mean comfortable.
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Which one of the following choices is the best explanation of why Isoflurane anesthetic gas is used with patients with kidney and liver disease? (A) Isoflurane is primarily excreted via the lungs (B) Isoflurane is rapidly metabolized by the liver and kidneys (C) The anesthetic effects are not prolonged (D) The anesthetic effects are not prolongedIsoflurane has a high solubility coefficient (E) Isoflurane can be used without a precision vaporizer
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Answer is A: Isoflurane is primarily excreted via the lungs. Only about 0.2% is removed via metabolism. Since metabolism is not required for removal, patients with liver or kidney disease can be anesthetized with isoflurane and recovery should not be prolonged. However, isoflurane and the other newer inhalant anesthetics DO have some effects on the kidney or liver. Decreased glomerular filtration and urine production can occur with inhalant anesthetics, and this can be exacerbated if hypotension occurs or if nephrotoxic drugs are used. Hepatic blood flow is usually maintained, but can also be impaired if hypotension develops. Good anesthetic management with attention to blood pressure and oxygenation are essential to prevent most complications.
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You are asked to set up a non-rebreathing anesthetic circuit for the next surgery case. What kind of patient do you expect?: (A) Miniature poodle under 7 kg (B) Siamese cat over 20 lbs (C) Greyhound with no body fat (D) Asthmatic bulldog
answer
Answer is A: A non-rebreathing anesthetic circuit is better for SMALLER animals, under 7 kg (under 15 pounds).
question
Which of the following patients is most likely to be suffering from neuropathic pain? (A) Canine or equine castration (B) Ovariohysterectomy in a cat (C) Horse with chronic laminitis (D) Cat with abscess
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Answer is C: A horse with chronic laminitis will suffer neuropathic pain . Neuropathic pain is pain that originates in the nervous system. This develops when direct damage to the nervous system occurs AND when chronic pain stimulates the reorganization of the pain response. The pain continues even after the tissue originally damaged is no longer painful. Treatments specifically for neuropathic pain include drugs used primarily for other illnesses/problems. Neuropathic pain does not respond or responds poorly to traditional analgesics such as opioids and non-steroidal anti-inflammatories. Gabapentin is used in the treatment of seizures; amitriptyline is an anti-depressant; amantadine is an anti-viral drug; dextropmethorphan is an anti-tussive agent; etc. Remember that all of the other patients listed can develop chronic and/or neuropathic pain if their pain is inadequately managed.
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For anesthetics, what does MAC, (Minimum Alveolar Concentration) measure? (A) Minimum safe concentration (B) Anesthetic fat solubility (C) Speed of expected induction (D) Anesthetic potency
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Answer is D: MAC, (Minimum Alveolar Concentration) is a measure of anesthetic potency. Technically, it is the minimum concentration of anesthetic in the alveolar gas that prevents a physical response in 50% of animals exposed to a surgical stimulus. Because you want to be 100% sure that an animal is completely anesthetized, you usually use MULTIPLES of MAC to determine vaporizer settings (ie:, 1-2X MAC) to guarantee anesthesia during surgery.
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Which of the following is a narcotic antagonist at the kappa receptor? (A) Pentazocine (B) Butorphanol (C) Naloxone (D) Diamorphine
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Answer is C: Naloxone is the most commonly used pure opioid antagonist used in veterinary medicine. Naloxone is effective at all the opioid receptors, (mu, kappa, and delta) but has a greater activity at the mu receptor. At very low doses, side effects may be reversed while preserving the analgesic effects. However, reversal must be performed with great care, as a sudden exacerbation of pain can result in adverse cardiovascular effects; even death is reported. A low dose is calculated and diluted with saline, then given very slowly intravenously. Butorphanol, nalbuphine, and pentazocine are opioid agonists at the kappa receptor, but are antagonists of the mu receptor, so they can be used to reverse adverse effects of mu opioid agonists. A low dose of butorphanol is often used to reverse dysphoria and/or respiratory depression in dogs and cats. Diamorphine is heroin.
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Why is it acceptable for an animal to rebreathe exhaled gasses in a closed or semi-closed anesthetic circuit?: (A) Exhaled gasses pass through a CO2 absorbent canister (B) Oxygen requirements of anesthetized animals are very low (C) Two-way valves prevent CO2 buildup (D) Modern anesthetic gasses remain potent for 2-3 inhalations
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Answer is A: Expired gasses pass through a CO2 scavenger canister to remove CO2. One-way valves help direct gas flow. The remaining oxygen and anesthetic gas recirculates with fresh incoming gas and is rebreathed by the animal. The higher the flow rate, the more CO2 is pushed through the absorbent canister and is not rebreathed
question
During induction of anesthesia with thiopental following premedication with acepromazine and hydromorphone, a dog at first seems to relax but then begins paddling with all four legs. He has nystagmus and is tossing his head back and forth. What is the correct interpretation of this scenario? (A) Hydromorphone or thiopental injected perivascularly, causing pain (B) Overdose - this is Stage IV with seizure activity due to cerebral hypotension (C) Anaphylactic reaction to hydromorphone, epinephrine should be given at once (D) Thiopental dose was inadequate, this is Stage II excitement
answer
Answer is D: This is the involuntary excitement of Stage II due to an inadequate dose of thiopental. As consciousness is diminishing, loss of voluntary control of movement occurs in Stage II of anesthesia. Patients can have violent jerky movements, often "paddle" with all 4 limbs. Horses and cattle,and some dogs and cats exhibit nystagmus. Excessive salivation and vomiting may also occur. Stage II begins with loss of consciousness and lasts until a regular respiratory pattern is present. Ideally, Stage II is bypassed with induction. Remember that muscle relaxation is poor with ketamine, and some patients may be stiff or show myoclonus with propofol or etomidate. This may be a temporary sign that will pass or another drug may be needed to produce relaxation
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What part keeps exhaled gasses moving away from the patient in a circular rebreathing anesthetic delivery system? (A) Rebreathing bag (B) One-way valves (C) Y-valve on endotracheal tube (D) Oxygen flush valve
answer
Answer is B: One way valves help direct gas flow. Expired gasses pass through a CO2 scavenger canister to remove CO2. STRATEGY HINT: See how the word "Valve" occurs in 3 choices? Chances are that the correct answer contains this word.
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Which one of the following choices is the correct explanation of the function of a pulse oximeter? (A) Automatically measures and records the pulse rate and rhythm (B) Measures the oxygen saturation of hemoglobin and pulse rate (C) Measures carbon dioxide concentration after every 10th pulse (D) Amplifies the pulse rate and oxygenation of venous blood without touching patient (E) Detects the flow of blood through small arteries and measure blood pressure
answer
Answer is B: A pulse oximeter is used primarily to measure the oxygen saturation of hemoglobin in arterial blood. A stable pulse is required for a good measurement, so the heart rate will also be measured. An espohageal stethoscope amplifies the sound of the heart to allow monitoring at a distance. An electrocardiogram (ECG) records heart rate and rhythm. A doppler monitor detects the flow of blood through small arteries and can be used to measure blood pressure.
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Which of the following corresponds to ventricular repolarization? (A) QRS wave, #3-5 (B) T wave, #6-7 (C) A wave, #2 (D) P wave, #1
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Answer is B: The T wave represents ventricular repolarization. The ventricular muscle is refractory to another depolarization at this time while the membrane potential of the myocardial cells reset to normal. The shape and direction of each waveform is affected by placement of leads and the recording selected. In horses, the best ECG is obtained using Lead I with electrodes attached in the base-apex arrangement. The P wave will be positive, the QRS is negative, and the T wave varies in direction. With Lead III, the direction of waveforms is opposite.
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When using an esophageal stethoscope, to what landmark should the catheter be inserted within the esophagus? (A) Point of the shoulder (B) 3rd rib (C) 7th rib (D) 5th rib (E) Back of the ribcage
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Answer is D: The catheter should be lubricated and inserted into the anesthetized animal's esophagus to the 5th rib (or approximately the level of the heart). Esophageal stethoscopes are a relatively inexpensive way to monitor the heartbeat and rate during anesthesia in small animals.
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Why might some rabbits need a higher dose of preanesthetic atropine? (A) Tachycardia prior to anesthesia (B) Breed-related atropinase (C) Tendency to salivate (D) Higher stress level prior to anesthesia (E) Bradycardia prior to anesthesia
answer
Answer is B: Some breeds of rabbits have endogenous atropinases, enzymes that inactivate atropine. These rabbits require a higher dose of atropine. Atropine is often given subcutaneously to rabbits prior to anesthesia to help minimize salivation. Rabbits should have food withheld for 8-12 hours prior to anesthesia in order to decrease the risk of regurgitation while anesthetized. It is recommended that rabbits be intubated during anesthesia. However, rabbits are difficult to intubate and stable patients do not definitively require it as they are unlikely to regurgitate.
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In which animal do you typically AVOID using Atropine (anti-cholinergic) as a premedication before inducing anesthesia? (A) Horse (B) Cat (C) Pig (D) Dog
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Answer is A: Atropine slows the gut, so there is concern that they might cause colic in HORSES. This is less likely with another anti-cholinergic, glycopyrrolate, so it is sometimes used to prevent bradycardia (slow heart rate) in anesthetized horses
question
Numerous pauses are heard on the Doppler of a dog anesthetized with isoflurane. The veterinary technician monitoring the dog is having trouble evaluating the heart rhythm from this electrocardiogram Which of the following is the main problem? (A) The wrong lead set up was used to record the ECG (B) This patient must be very large, the waveforms don't fit on the paper (C) The paper speed is too slow (D) Respiratory motion has distorted the baseline
answer
Answer is D: Respiratory motion has distorted the recording, causing the undulating wave-like baseline seen. To correct this, move the lead attachments further away from the chest, or select a different lead (Lean I or III) to see if this artifact remains. When the recording was corrected, second degree AV block was discovered, as seen in this ECG. This is a good example of one advantage of using a Doppler blood pressure monitor - since cardiac pulsations are continuously audible, it is obvious when an arrhythmia occurs. Click link for excellent website - Interpretation of ECGs from UPenn.
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Which of the following is an indicator of oxygenation? (A) Mucous membrane color (B) Eye position (C) Respiratory rate (D) Blood pressure (E) Heart rate and pulse strength
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Answer is A: Oxygenation can be assessed by mucous membrane color, pulse oximetry, and blood gas evaluation. The mucous membranes are a very crude assessment of oxygenation. They will become cyanotic in nonanemic animals with severe deoxygenation, but this does not allow for timely intervention at less severe levels of deoxygenation.
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Which of the following is the most common sign of pain in animals? (A) Tachycardia and/or tachypnea (B) Behavior change (C) Anorexia post-operatively (D) Swelling and erythema of the incisio
answer
Answer is B: Changes in behavior are the most common and reliable signs of pain in animals. Painful animals will usually resist interaction with humans, hide in the back of their cage (cats especially), seem quieter than normal, vocalize, may bite or become aggressive, resent handling, and may not eat or drink normally. Physiologic abnormalities such as increases in heart rate or respiration can be due to pain but they are also caused by the anxiety/fear associated with hospitalization. Alterations of homeostasis such as dehydration, hypovolemia, electrolytes, etc, and the effects of numerous drugs may also affect heart rate, blood pressure, and even temperature.
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Which decongestant and anti-cough medicine is also used in anesthetic induction protocols in horses? (A) Diphenhydramine (B) Guaifenesin (C) Dextromethorphan (D) Acepromazine
answer
Answer is B: Guaifenesin is an anti-tussive (anti-cough) and decongestant medication that also works as a muscle relaxant. Guaifenesin is often used to provide a smooth anesthetic induction and maintenance in horses. FYI-In horses, Butorphanol (Torbugesic®) is a commonly used opiate with analgesic (anti-pain) and anti-tussive properties. Diphenhydramine is just another name for the antihistamine decongestant Benadryl®, used to treat anaphylaxis (immediate whole-body allergic reaction) in horse. Dextromethorphan is a cough suppressant, but it is not used to induce anesthesia. Acepromazine is a sedative, but not a cough suppressant.
question
A dog under anesthesia for teeth cleaning develops a sinus bradycardia (heart rate 50 beats per minute). One minute following treatment with atropine, an irregular rhythm is identified on the Doppler and the electrocardiogram, seen in the image below. Which of the following correctly identifies this rhythm? (A) Second degree AV block (B) Atrial fibrillation (C) Respiratory sinus arrhythmia (D) Asystole
answer
Answer is A: This dog has second degree AV block which is a failure of conduction through the AV node. Atropine may initially cause a transient slowing of heart rate (HR) and AV block as low doses stimulate presynaptic inhibitory receptors. As drug level increases, muscarinic blockade predominates and HR increases. The ECG is characterized by occasional P waves without a QRS that follows. There is a 'dropped beat' as the ventricles do not contract. This rhythm is heard as a pause equal to 2X the normal R-R interval.
question
Which of the following patients will benefit the most from the use of pre-emptive analgesia? (A) Horse with chronic laminitis (B) Cat for an amputation following hit by car (C) German shepherd with osteosarcoma of the humerus (D) Dog presented for ovariohysterectomy
answer
Answer is D: A dog presented for ovariohysterectomy will benefit the most from the use of pre-emptive analgesia analgesia because she is not painful prior to surgery. Pre-emptive means to intervene prior to an expected event or consequence. Treatment prior to beginning of surgery minimizes sensitization of the pain and stress responses, and results in fewer complications and shorter hospital stays. The pain response is already highly stimulated in all the other patients listed. Chronic pain is present in the german shepherd with osteosarcoma and the horse with laminitis. These patients will have central sensitization and neuropathic pain as these develop with direct damage to the nervous system and when the pain response is exaggerated via sensitization
question
Following induction of anesthesia with thiopental, a regularly irregular heartbeat is heard on the doppler in a 5 year old dachshund being anesthetized for a myelogram. An electrocardiogram is performed, shown in the image below. Which one of the following choices correctly identifies the arrhythmia in this patient? (A) Premature supraventricular contractions (B) Atrial tachycardia (C) Ventricular bigeminy (D) Idioventricular tachycardia (E) Second degree atrioventricular block
answer
Answer is C: Ventricular bigeminy is a regularly irregular rhythm in which each sinus beat is followed by a premature ventricular contraction (PVC) such that the normal/abnormal beats appear to occur in pairs. PVCs lack a p wave and the QRST waveforms are usually wide and bizarre in appearance. Click here to see an illustration of the answer. Ventricular bigeminy (VB) is a common arrhythmia seen following induction with thiobarbiturates. It usually only lasts a few minutes and may often be missed unless the pulse is being monitored. VB that occurs at induction with thiobarbiturates usually does not require treatment as it most often disappears as the drug level falls, and sympathetic tone decreases as the level of inhalant anesthetic increases. Intermittent PVCs are also not uncommon following induction of anesthesia since many drugs sensitize the myocardium to the development of arrhythmias at the same time that sympathetic release is temporarily increased. REMEMBER myocardial sensitization (drugs) and excitement of induction (sympathetic release) = potential for arrhythmias. Be sure to check the anesthetic depth, blood pressure, ventilation, and oxygenation immediately when an arrhythmia develops.
question
Which of the following correctly describes the phenomenon of allodynia? (A) Stimuli that are not normally painful produce a pain response (B) Painful reaction occurs when other members of species are stimulated (C) Lack of reaction to a typically painful stimulus (D) Decreased reaction to stimuli that usually cause pain (E) A heightened sense of pain to normally painful stimuli
answer
Answer is A: Allodynia is pain produced by stimuli that are not normally painful. Hyperalgesia is an exaggerated response to a painful stimuli. Hypoalgesia is a decreased response to a painful stimuli. A decreased analgesic effect is seen with tolerance to pain medication develops. Both hyperalgesia and allodynia develop with severe acute or chronic pain when there is pathologic pain and central or peripheral hypersensitization. Low-threshold sensory nerve fibers are believed to be involved in the development of both hyperalgesia and allodynia. Following excessive stimulation from numerous sources, the response patterns of A-beta and C fiber pain receptors gradually change. Also, A-beta fibers, which normally respond only to innocuous stimuli, such as touch, develop painful responses.
question
Which of the following correctly describes the phenomenon of hyperalgesia? (A) Exaggerated reaction to a normally painful stimulus (B) Protective response to an actual or potentially damaging insult (C) Absence of response to a typically painful stimuli (D) Stimuli that are not normally painful produce a pain response (E) Increased analgesic effect seen when treating a patient in pain
answer
Answer is A: Hyperalgesia is an exaggerated response to a normally painful stimulus. Trauma and inflammation in the tissue cause central or peripheral sensitization. The patient then responds at lower levels of input and to stimuli that normally would not produce a response. Physiological pain is the protective response to an actual or potentially damaging insult. Allodynia is when stimuli that are not normally painful produce a pain response. For more information, see the Taxonomy of Pain from the IASP, How to Pinpoint Pain in small animals from the Am. Animal Hospital Assoc., and the Veterinary Anesthesia and Analgesia Support Group.
question
A healthy, one year old cat that was castrated under anesthesia with dexmedetomidine, butorphanol, and ketamine. The cat is placed in recovery after 45 minutes. A dose of meloxicam and buprenorphine were given for post-operative analgesia. 30 minutes into recovery, the cat is found in his cage lying quietly in sternal recumbency. He rouses a bit when stimulated, but remains quiet if left alone. His heart rate is 140 beats per minute [N 140-190], mucous membranes are pink, capillary refill time is 1-2 seconds. Which of the following is the best step to take next? (A) Wrap the cat in warm towels and place on a heating pad to treat hypothermia (B) No intervention is needed - continue monitoring (C) Put a small amount of honey or karo syrup on the tongue to reverse hypoglycemia (D) Submit blood sample for electrolytes and hematocrit
answer
Answer is B: No intervention is needed. This cat is comfortable; very good pain management is present for a mild to moderately painful procedure. The usual doses of dexmedetomidine, butorphanol, and ketamine used in a healthy cat provide about an hour of anesthesia for minor surgical procedures such as a castration. Complete recovery takes approximately 2-3 hours with this combination. When good pain management is present, patients will rest quietly following anesthesia, often sleep for awhile, and behave normally during interaction with caretakers. Changes in behavior are more indicative of pain than are physiologic variables such as heart rate, blood pressure, etc. Excellent review of pain in cats: SA Robertson. Managing Pain in Feline Patients. Vet Clinics of NA: SA Practice 2008; 38: 1267-90.
question
What part of an anesthetic circuit absorbs carbon dioxide? (A) Flexible reservoir bag (B) Soda lime canister (C) Precision vaporizer unit (D) Exhalation valve
answer
Answer is B: A canister of soda lime granules in the anesthetic circuit absorbs carbon dioxide from exhaled anesthetic gasses. Fresh absorbent crystals are white and can be crushed. But exhausted, saturated crystals become a distinct off-white color and are hard. Most granules contain a pH-sensitive dye that becomes visible as the absorbent granules become saturated. (The color itself is not so important as the color changing). A color change from white to purple or violet typically indicates that the CO2 scavenger granules have become saturated with CO2, but this color change does not always happen, and will dissipate after a few hours.
question
All of the following statements about the sedative acepromazine maleate are true EXCEPT: (A) May need to decrease dosage in geriatric animals (B) Giant dog breeds and sight hounds may be overly sensitive (C) May cause significant hypertension (D) May cause penile protrusion in horses
answer
Answer is C: Acepromazine may cause significant HYPOtension, NOT hypertension. Acepromazine maleate is a phenothiazine tranquilizer used as a sedative in many animals, as an anti-emetic to control motion-sickness in dogs and as a pre-anesthetic (often with atropine). Remember 4 things about Ace: 1. NO ANALGESIC effects 2. Giant dog breeds and sight hounds may be overly sensitive. 3. Although a rare occurrence (1:10,000 or less) it may cause persistent PROTRUSION of the PENIS in horses. 4. DECREASE the DOSE in debilitated and geriatric animals. Refs: Plumb's Veterinary Drug Handbook, 7th ed. pp. 4-8 and the Merck Veterinary Manual online edition.
question
What color is a nitrous oxide tank supposed to be? (A) Yellow (B) White (C) Red (D) Blue
answer
Answer is D: No matter what color the tank is, ALWAYS read the tag or label on the tank first to verify the gas contents inside. One instructor in Surgical Nursing and Anesthesia has reported seeing of a green tank containing carbon dioxide instead of oxygen! That being said, nitrous oxide tanks, (laughing gas) are blue. (Try remembering-"Laughing gas chases the blues") Oxygen tanks in the U.S are typically white or green.
question
Which of the following is the correct description of pre-emptive analgesia? (A) Use of an antagonist to reverse dangerous side effects of an analgesic medication (B) Administration of pain medication prior to elective surgery and stimulation of the pain response (C) Use of higher doses of pain medication given previously to a patient to achieve adequate analgesia (D) The combination of different types of analgesic medications and procedures to treat pain (E) Treatment with pain medication during surgery and prior to recovery of a patient
answer
Answer is B: Administration of pain medication prior to elective surgery / stimulation of the pain response is pre-emptive analgesia. Giving analgesics before the pain starts is the best way to minimize the pain response in a healthy patient who is not painful prior to surgery. Fewer complications and shorter hospital stays are seen when patients are comfortable following painful procedures. Analgesic therapy should be continued perioperatively and postoperatively for a few days to weeks depending on the procedure. Dosing should be decreased gradually and then stopped. Tolerance is seen when higher doses of pain medications are required. This occurs with opioids. Using combinations of different types of analgesic medications and procedures is multi-modal analgesia/anesthesia. Better analgesia and sedation are usually seen with combination therapy; lower doses can often be utilized as synergistic effects are common.
question
Why are atropine or glycopyrrolate (anti-cholinergics) often given as a premedication to dogs and cats before inducing anesthesia with ketamine or tiletamine? (Dissociative anesthetics) (A) Slows the heart rate (B) Increase airway secretions (C) Decrease salivation (D) Helps keep eyes closed
answer
Answer is C: Anti-cholinergics like atropine or glycopyrrolate are given as pre-meds to DECREASE salivation, DECREASE airway secretions and INCREASE heart rate. They do NOT affect whether eyes are open or closed, but they do DILATE the pupils. Remember that many anesthetic drugs (like opiates, barbiturates, gas anesthetics) promote bradycardia (slowed heart rate) and some dissociative anesthetics (like ketamine, tiletamine) cause excessive salivation.
question
How long should food routinely be withheld from young puppies (8 weeks and under) prior to anesthesia? (A) No time (B) 2-4 hours (C) 6-8 hours (D) 12-18 hours (E) 4-6 hours
answer
Answer is A: Food and water should NOT be withheld from puppies and kittens (less than 8 weeks old) for any length of time because they can rapidly become hypoglycemic and deteriorate without food. Fasting is often recommended prior to the induction of anesthesia to minimize the risk of regurgitation of stomach contents into the esophagus and pharynx. This can occur under anesthesia because lower esophageal sphincter tone decreases, swallowing reflexes are sluggish, and patients may experience nausea or vomiting. Regurgitation under anesthesia can lead to aspiration pneumonia, esophagitis, or esophageal stricture. Typical fasting times for mature animals are as follows: dogs and cats, 8-12 hours; small ruminants, 12-18 hours; horses, 8-12 hours; cattle, 24-48 hours.
question
Which of the following analgesic drug combinations should not be used simultaneously in dogs and cats? (A) Carprofen and hydromorphone (B) Meloxicam and dexamethasone (C) Midazolam and medetomidine (D) Fentanyl patch and firocoxib (E) Acepromazine and butorphanol
answer
Answer is B: Meloxicam (ML) and dexamethasone (DEX) should not be used concurrently because the risk of GI ulceration is much higher when a non-steroidal anti-inflammatory agent and a corticosteroid are used simultaneously. ML inhibits cyclooxygenase, DEX inhibits phospholipase2, the precursor of arachidonic acid. Both drugs affect the pathway necessary to produce certain prostaglandins that are important in protection of blood flow in the mucosa of the stomach and intestine. Dexamethasone has analgesic properties, however, it is used only on a short term basis because of side effects. It is beneficial in certain cases such as brain edema, spinal cord swelling from disk disease or neoplasia, etc., and intraarticularly for chronic arthritis. The endocrine, immune, and gastrointestinal side effects preclude long term use in most animals.
question
Which of the following correctly describes pathologic pain? (A) Increased response to a stimulus that normally produces pain (B) A protective response to an actual or potentially damaging insult (C) Stimuli that are not normally painful produce a pain response (D) Pain that goes beyond that needed to protect the patient from injury
answer
Answer is D: Pathologic pain is a response that is heightened beyond that needed to protect the patient from injury. This type of pain develops following the response to tissue damage that occurs with trauma or surgery. Both peripheral and central sensitization develops, which amplifies the pain response. In contrast, physiologic pain is an acute, protective response to an actual or potentially damaging insult, while hyperalgesia is an increased response to a stimulus that normally produces pain. Allodynia is present when stimuli that are not normally painful produce a pain response. Lack of response to stimuli that usually cause pain is hypoalgesia.
question
Which anesthetic drug can cause seizures if given in high doses? (A) Barbiturates (B) Dissociative anesthetics (C) Xylazine (Rompun®) (D) Benzodiazepine tranquilizers
answer
Answer is B: Dissociative anesthetics, like ketamine or tiletamine, can cause seizures at high doses. In contrast all three of the other drugs listed here are sedatives.
question
Which of the following effects are seen with high doses of isoflurane? (A) Decreased cardiac output, ileus (B) High systolic arterial blood pressure, loss of corneal reflex (C) Nausea, tachypnea (D) Tachycardia, vomiting (E) Respiratory depression, seizures
answer
Answer is A: Ileus and decreased cardiac output can be seen with high doses of isoflurane. At high doses, cardiac output is DECREASED by all the inhalant anesthetics (including isoflurane) due to myocardial depression. This effect is most significant at deeper levels of anesthesia and in sick patients. At anesthetic concentrations of isoflurane used clinically, cardiac output is usually within the normal range but blood pressure may be decreased due to vasodilation. Vomiting, nausea, and respiratory depression are also seen with high doses of isoflurane.
question
Ketamine is contraindicated for dogs having history of which problem? (A) Epilepsy (B) Bradycardia (C) Decreased intraocular pressure (D) Polyuria, polydipsia
answer
Answer is A: Ketamine can cause seizures in some dogs (epilepsy is a form of seizure). Ketamine is contraindicated (do not use it) in dogs with increased intra-ocular pressure (like glaucoma) and can cause respiratory depression. Other contraindications include prior hypersensitivity reactions, animals to be used for human consumption, use of ketamine alone for general anesthesia and increased CSF pressure or head trauma. Remember to protect a cat's eyes with ophthalmic ointment when using ketamine, because they remain open after injection.
question
What is the approximate normal tidal volume of an animal? (A) 3-5 mL/kg body weight (B) 25-30 mL/kg body weight (C) 15-20 mL/kg body weight (D) 5-10 mL/kg body weight (E) 10-15 mL/kg body weight
answer
Answer is D: The approximate normal tidal volume (or VT) is 10-15 mL/kg body weight. The VT is the volume of air that moves in and out of the lungs during each normal breath. Ref: Bassert and Thomas, McCurnin's Clinical Textbook for Veterinary Technicians, 8th edition, p. 1096.
question
Which animal is routinely intubated blindly without use of a laryngoscope or digital palpation? (A) Camelids (B) Pigs (C) Horses (D) Goats (E) Cattle
answer
Answer is C: Horses are almost always intubated blindly. Digital palpation is used for cattle. Laryngoscopes can be helpful in visualizing the larynx for endotracheal tube placement. They can have straight blades (Miller blades) or curved blades (McIntosh blades) and range in size from 0-5 (small-large). They are routinely used in pigs, camelids, and small ruminants. They are sometimes used in dogs and cats.
question
Which sedative typically causes the least cardiac and respiratory depression? (A) Butorphanol (B) Dexmedetomidine (C) Acepromazine (D) Propofol (E) Xylazine
answer
Answer is C: Acepromazine causes the least respiratory and cardiac depression of the agents listed. It is a phenothiazine tranquilizer that causes mild sedation. It is often given in combination with other agents as a pre-anesthetic or for stronger sedation. Xylazine and dexmedetomidine are alpha-two adrenergic agonists used as sedatives. They can cause significant bradycardia, reduction in cardiac output, hypotension, cardiac arrhythmias, and respiratory depression. Butorphanol is a mixed opioid agonist-antagonist. It can cause respiratory depression and bradycardia. Propofol can lead to significant respiratory depression, apnea, bradycardia, and decreased cardiac contractility.
question
The corneal reflex may be absent during what stage of general anesthesia? (A) Stage II, plane II (B) Early stage III (C) Stage IV (D) Stage 1, plane I
answer
Answer is C: The corneal reflex may be absent during Stage IV, which is an overdose of anesthesia-the patient will be very close to death. The corneal reflex should NEVER be gone if the patient is at an appropriate depth of anesthesia, unless the patient is paralyzed with a neuromuscular blocker. The corneal reflex does not always disappear, in fact, it is still present for a short time after death in some patients. It is not wise to use the corneal reflex routinely to determine anesthetic depth as it could be damaged with frequent touch. Also, it is often not available in dogs and cats since the eyeball rolls ventrally. Other reflexes and signs of anesthetic depth are quite reliable - palpebral response, eye position, tearing, nystagmus, etc. Note - there are no planes of anesthesia in stages I or II.
question
What fresh gas flow rate is typical of a non-rebreathing anesthetic circuit? (A) 30-50 ml/kg/min (B) 300-450 ml/kg/min (C) 100-300 ml/kg/min (D) 50-150 ml/kg/min
answer
Answer is C: Fresh gas flow rates in NON-rebreathing system are HIGH, varying from 100-300 ml/kg/min, depending on your system. A high flow rate like this will help remove exhaled gases. In general, NON-rebreathing anesthetic systems use HIGH flows, and are best for SMALL animals under 7 kg. This system will also work as partial rebreathing with flow rate at or below 130 ml/kg/min.
question
How long does the analgesic effects of butorphanol last? (A) 8 hours (B) Butorphanol has no analgesic effects (C) Up to 3 days (D) 2 hours (E) 45 minutes
answer
Answer is E: The analgesic effects of butorphanol, a kappa opioid agonist and mu opioid antagonist, typically last only 45 minutes, while the sedative effects last at least 2 hours. The analgesic effects of buprenorphine, a partial mu opioid agonist, last up to 8 hours. Fentanyl is a very potent opioid and the analgesic effects of the patches last up to 3 days.
question
Which choice is often used in combination with ketamine or thiopental to induce anesthesia in horses? (A) Naloxone (B) Halothane (C) Guaifenesin (D) Phenobarbital
answer
Answer is C: Guaifenesin is an anti-tussive (anti-cough) and decongestant medication that also works as a muscle relaxant. It is often used to support a smooth anesthesia induction and recovery in horses. Naloxone is a reversal agent for opiate drugs (In horses, Butorphanol (Torbugesic®) is a commonly used opiate). Gas anesthesia (like halothane) would not work to mask a horse down into anesthesia because you would expect problems restraining the animal during the excitement phase of induction. Halothane has largely been replaced by newer inhalant anesthetics, like isoflurane and sevoflurane Phenobarbital is a long-acting barbiturate used to control epilepsy/seizures, not induction of anesthesia
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A dog is anesthetized for ovariohysterectomy with isoflurane in oxygen following premedication with atropine, acepromazine, and hydromorphone given intramuscularly, and intravenous induction with midazolam and ketamine. As the surgeon exteriorizes the first ovary, the dog's blood pressure increases and the heart rate goes down. What is this phenomenon? (A) Baroreceptor response (B) The Valsalva maneuver (C) Symphathetic release (D) Vago-vagal reflex
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Answer is A: This is an example of the baroreceptor response or reflex that relates heart rate (HR) and blood pressure (BP). It is sometimes also called Marey's reflex. To maintain perfusion, BP is kept within a particular range. When BP increases, HR goes down, when BP decreases, HR goes up. The BP increase is usually because of an increase in sympathetic tone. This causes a corresponding increase in parasympathetic tone (via the vagus nerve) that slows HR. Anesthestic drugs and adjunct medication may accentuate (alpha 2 agonists), attenuate (inhalants) or abolish (anti-cholinergics) this response.
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Immediately after surgery, a dog wakes from anesthesia breathing quickly, vocalizing, rolling, thrashing, and mutilating herself. What is the correct name for these aberrant behaviors? (A) Allodynia (B) Nociception (C) Dysphoria (D) Wind-up phenomenom (E) Hyperalgesia
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Answer is D: Dysphoria is aberrant behavior seen immediately after surgery as an animal awakes from anesthesia. It includes vocalizing, rolling, tachypnea, thrashing, and self-mutilation. It is also sometimes referred to as "emergence delirium" because it may be due to residual anesthetics within the animal's system. These animals should be rapidly treated as the phenomenom leads to physiological and emotional stress. Nociception is the processing of pain, including transduction, transmission, and modulation. Wind-up phenomenom (or "central sensitization") occurs when spinal neurons are subjected to high-intensity or repeated nociceptive impulses. Even after the stimulus is removed, the neurons become increasingly, progressively excitable. Hyperalgesia is the first part of the wind-up phenomenom process. Less stimulation initiates pain because the pain threshold is lowered. Allodynia is the second part of wind-up phenomenom. Nerve fibers that typically carry neutral or pleasant information instead transmit pain.
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How do you prevent laryngospasm in cats before inducing anesthesia? (A) Avoid halothane (B) 1-2% Lidocaine spray (C) Pre-medicate with atropine or glycopyrrolate (D) Pre-medicate with acepromazine
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Answer is B: Prevent laryngospasm by spraying larynx with 1-2% lidocaine. Laryngeal spasm is primarily a CAT problem associated with overzealous manipulation of the larynx by laryngoscope or during intubation.
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In which of the following animals would it be appropriate to use a cuffed endotracheal tube? (A) 4-week-old kitten (B) African gray parrot (C) Ferret (D) Adult Rottweiler
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Answer is D: Use a CUFFED endotracheal tube in an adult dog. Use UNcuffed tubes in ferrets and very small animals (puppies, kittens) to preserve a larger airway diameter. Use Uncuffed in birds because they have complete tracheal rings that make their trachea less compliant (flexible) when an endotracheal tube cuff is inflated. An endotracheal tube goes between the vocal folds of the trachea ("endo" equals "into" the trachea!). Typically you inflate the cuff around the end of the tube to seal the airway.
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Which two drugs are contraindicated in animals with a history of seizures? (A) Xylazine, thiopental (B) Ketamine, diazepam (C) Acepromazine, ketamine (D) Morphine, phenobarbital
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Answer is C: Acepromazine, ketamine, and xylazine are contraindicated in animals with a history of seizures. Thiopental is contraindicated in animals with history of asthma, because it can cause apnea, and in Greyhounds. Morphine should not be used in cases with high intracranial pressure (like head trauma after being hit by a car). Diazepam and phenobarbital are drugs used to TREAT seizures. STRATEGY HINT: This is a "frequency" question. That is, you can see how the choice "ketamine" is repeated, twice. Chances are that the correct choice will include the word that is repeated the most often. In this case, even if you have no idea what the right answer may be, simply narrowing down to the two answer choices that include ketamine will increase your chances of picking correctly to 50:50 ! NOTE- if you know the correct answer without the aid of study tricks like this, choose the answer your brain tells you is correct. These kinds of study tricks are only a guide to use if you are lost, they are NOT a guarantee of getting the answer right every time.
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In which animal is arterial catheterization routinely performed during inhalant anesthesia lasting more than 1 hour? (A) Pigs (B) Ferrets (C) Horses (D) Cats (E) Reptiles
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Answer is C: It is recommended to place arterial catheters in horses undergoing inhalant anesthesia lasting more than 1 hour. This allows for continuous direct blood pressure assessment and blood gas sampling at least every 30-60 minutes. This is recommended because horses are prone to the development of hypoxemia, hypoventilation, and hypotension during inhalant anesthesia.
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What will happen if you hit the oxygen flush button on an anesthetic machine? (A) Oxygen is flushed out of the system (B) The patient will go to a deeper anesthetic plane (C) Anesthetic gas concentration goes up in the breathing circuit (D) The patient may start to wake up
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Answer is D: The oxygen flush sends pure oxygen into the breathing circuit, BYPASSING the vaporizer. Anesthetic gas concentration DECREASES, and patients start to wake up. Remember you should NOT hit the oxygen flush button if the pop-off valve is closed, or when using a non-rebreathing system, because you can deliver dangerously high airway pressure to the patient. STRATEGY HINT: This is a kind of "frequency" question. That is, you can see how the choice "wake up" and the "deeper anesthesia" choice are flip sides of the same possibility. (Kind of like being repeated, or increased frequency!). Chances are that the correct choice will include the choice that is repeated the most often. In this case, even if you have no idea what the right answer may be, simply narrowing down to the two answer choices will increase your chances of picking correctly to 50:50 !
question
Which of the following correctly describes the function of the nociceptors? (A) Transduce painful stimuli into electrical signals for transmission to the spinal cord and brain (B) Modulate nerve impulses arriving from the periphery into the spinal cord (C) Transmit painful stimuli via A-beta fibers to first order neurons in the spinal cord (D) Perceive innocuous stimuli in the cerebral cortex and coordinate the emotional and physical response
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Answer is A: Nociceptors are specialized receptors for painful and noxious stimuli. They transducer these stimuli into electrical signals that are then transmitted to the spinal cord and brain for processing and perception. The nociceptors are free nerve endings located on A-delta and C afferent nerve fibers, found in the skin, subcutaneous tissue, viscera, joints, periosteum, and muscle. Nerve endings on A-beta fibers normally respond to non-noxious stimuli - touch, pressure, vibration, motion, and proprioception. Common names for these receptors are Meissner's, Merkel's, Pacini's, and Ruffini's; they are highly sensitive and are located in skin, muscles, and joints Overlap exists between the response of nociceptors such that stimuli that begin as innocuous sensations can be quickly perceived if/when they become painful.
question
A surgical repair of a patent ductus arteriosus was performed via thoracotomy in a 4 month old Labrador puppy. In recovery, the puppy is found in his cage, crying and whining. His breaths are short and fast. When a technician attempts to comfort him, he tries to get away, cowers in the corner, and cries louder. Which of the following is the best explanation of this scenario? (A) This is the clinical picture of opioid dysphoria (B) Labradors often do this in recovery, they have low pain tolerance (C) This puppy is painful, pain management is inadequate (D) Recovery is prolonged, stage II signs are still occurring
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Answer is C: This puppy is painful, pain management is inadequate, as these are signs of pain. Behavioral changes are the most reliable signs of pain in animals. Tolerance levels and socialization skills certainly vary in all species, however, signs of pain should be anticipated, repeatedly evaluated, and treated in all cases. A thoracotomy is one of the most painful procedures performed in animals and humans. Intense pain management is required, including: 1)an opioid in combination with a tranquilizer or sedative, 2) a non-steroidal anti-inflammatory agent, and 3) intercostal and intrapleural nerve blocks with a long acting local anesthetic, e.g. bupivacaine. Continuous infusion of lidocaine, ketamine, and/or an opioid such as fentanyl or morphine provides excellent analgesia and some sedation. This can replace # 1 above. Shallow respiration is common in patients with chest pain; hypoventilation and hypoxemia can result. Opioids can depress respiratory function, but adequate pain management will improve ventilation when it doesn't hurt so much to breathe. Although labrador puppies are generally most gregarious and responsive to people, they still exhibit signs of pain when present. Sometimes we need to look very closely; don't believe that wagging tail!
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A cat is anesthetized for ovariohysterectomy (OHE) with isoflurane in oxygen after premedication with atropine, acepromazine, and hydromorphone intramuscularly, and induction with midazolam and ketamine intravenously. As the surgeon exteriorizes the first ovary for ligation, the cat's heart rate, blood pressure, and respiratory rate begin to increase rapidly, but she does not move. Which of the following is the next best step? (A) Raise the inspired oxygen flow rate to a higher setting (B) Increase the isoflurane vaporizer setting (C) Put the cat on a ventilator (D) Administer a dose of dexmedetomidine intramuscularly
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Answer is B: This cat is light and anesthetic depth should be increased. The simplest way to increase depth in this patient is to increase the isoflurane setting and manually ventilate the cat for a short time. Surgical stimulation raises sympathetic tone, which increases heart rate (HR), blood pressure (BP), and respiratory rate (RR). Anesthetic depth is adjusted in proportion to the intensity of surgical stimulation. Increases in HR, RR, or BP do not necessarily mean the patient feels pain as awareness is lost before the autonomic response to surgery. Response during OHE is common at the skin incision, and with tension on the ovarian ligaments or uterus. If high levels of inhalant are needed or the BP drops too low, a dose of an analgesic or sedative many be necessary.
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Which of the following is the correct explanation of pre-emptive analgesia? (A) Administration of pain medication prior to stimulation of the pain response (B) Use of higher doses of pain medication given previously to a patient to achieve adequate analgesia (C) The combination of different types of analgesic medications and procedures to treat pain (D) Use of an antagonist to reverse dangerous side effects of an analgesic medication
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Answer is A: Administration of pain medication prior to stimulation of the pain response is pre-emptive analgesia. Giving analgesics before the pain starts is the best way to minimize the pain response in a healthy patient who is not painful prior to surgery. Fewer complications and shorter hospital stays are seen when patients are comfortable following painful procedures. Analgesic therapy should be continued perioperatively and postoperatively for a few days to weeks depending on the procedure. Dosing should be decreased gradually and then stopped. Tolerance is seen when higher doses of pain medications are required. This occurs with opioids. Using combinations of different types of analgesic medications and procedures is multi-modal analgesia/anesthesia. Better analgesia and sedation are usually seen with combination therapy; lower doses can often be utilized as synergistic effects are common.
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A young cat is under general anesthesia for a routine ovariohysterectomy. The technician notices that the cat has stopped breathing and her mucous membranes are a muddy blue color. (A) Ventilate the cat (B) Ensure airway, oxygen supply, and breathing circuit are open (C) Give a specific sedative antagonist if available (D) Stop anesthetic administration and assess for cardiac arrest (E) Check for a pulse and measure blood pressure
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Answer is D: Although all of the answers should be performed, there is little time to revive a patient in cardiac arrest. The first step should be - stop administration of inhalant anesthetic and quickly assess cardiovascular status, ie, check for pulse/heart rate. The technician should call for help to aid in a thorough assessment of the patient and performance of cardiopulmonary cerebral resuscitation (CPR) if required. Even though patients that arrest under general anesthesia have a better chance for recovery, Interruption of or delay in performance of cardiac compressions is associated with poorer outcomes. The use of anesthetic monitors that constantly evaluate cardiovascular function and the presence of an anesthesia technician at all times has been shown to greatly improve outcome in cases with cardiac arrest.
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Which anesthetic induction agent is also a decongestant and antitussive? (prevents coughing) (A) Ketamine (B) Guaifenesin (C) Phenobarbital (D) Propofol
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Answer is B: Guaifenesin is an anti-tussive (anti-cough) and decongestant med that also works as a muscle relaxant. Guaifenesin is often used to support excitement-free anesthesia induction and recovery in horses. Phenobarbital is a long-acting barbiturate used to control epilepsy/seizures, not induce.
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Which of the following patients will benefit the most from the use of pre-emptive analgesia? (A) German shepherd with osteosarcoma of the humerus (B) Horse with chronic laminitis (C) Dog presented for ovariohysterectomy (D) Dachshund with intervertebral disk disease (E) Cat needing limb amputation after being hit by car
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Answer is C: A dog presented for ovariohysterectomy will benefit the most from the use of pre-emptive analgesia because she is not painful prior to surgery. Pre-emptive means to intervene prior to an expected event or consequence. Treatment prior to beginning of surgery minimizes sensitization of the pain and stress responses, and results in fewer complications and shorter hospital stays. Analgesics are often combined with sedatives as premedication. This also decreases the stress response and helps make the entire episode of anesthesia and surgery smooth and less or un-eventful. The pain response is already highly stimulated in all the other patients listed. Chronic pain is present in the german shepherd with osteosarcoma and the horse with laminitis. These patients will have central sensitization and neuropathic pain as it is seen in chronic pain and with direct damage to the nervous system. Neuropathic pain is also present in the dachshund since damage to spinal nerves is seen with disk disease.
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When is the best time to refill the vaporizer in an anesthetic machine in a small animal clinic? (A) Depends on the type of breathing circuit (B) When the fewest people are in the clinic (C) Whenever the fill volume is below 50% (D) When the CO2 absorbent granules are completely purple (E) After each surgery
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Answer is B: The best time to refill the anesthetic vaporizer in a small animal clinic is when the least number of people are around that could be exposed to anesthetic vapors that escape into the room. After filling the vaporizer, it is best to leave the room if possible so that exposure to vapor is minimized. It is also good to leave a machine ready to go in the evening for potential emergencies. In large animal practice - a full vaporizer being used on an adult horse or cow will need to be refilled every 2.5-3 hours or so, because the volume of inhalant used is so much greater in large animal patients. Therefore, exposure is sometimes unavoidable during long procedures.
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What type of anesthetic breathing circuit is a Bain system run at a high flow rate (200-300 ml/kg/min)? (A) Nonrebreathing (B) Closed system (C) Semi-closed system (D) Partial rebreathing
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Answer is A: A Bain anesthetic circuit run at a high flow rate of 200-300 ml/kg/min will not allow rebreathing of exhaled gasses. Remember that a Bain system is like a tube within a tube. New oxygen and anesthetic gas is inhaled down the inner tube, and exhaled gas exits through the outer tube. At flow rates of 130-200 ml/kg/min or less the Bain functions as a partial rebreathing system, and the animal rebreathes some of the exhaled gasses Semi-closed and partial rebreathing systems are the same thing. They run at intermediate flow rates where fresh gas is delivered in excess of metabolic consumption, from about 10 ml/kg/min (large animals) or 30 ml/kg/min (small animals). A closed anesthetic rebreathing system only provides enough fresh gas flow to meet an animal's metabolic needs, about 5-10 ml/kg/min (depending on animal size. Flow is lower for larger animals and higher for smaller animals)
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Which one of the following monitors is used to continuously measure blood oxygen saturation (SaO2) in anesthetized and critical care patients? (A) Plethysmograph (B) Electrocardiograph (C) Pulse oximeter (D) Oscillometry
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Answer is C: The pulse oximeter continuously measures blood oxygen saturation (SaO2), the percentage of hemoglobin molecules in arterial blood saturated with oxygen. SpO2 just means the SaO2 measurement as determined by PULSE oximetry. Pulse oximetry determines the absorption of light as it passes through tissues. The device is usually placed on the tongue, but the toe web, flank skin, ears, or lips. Two wavelengths of light are used, one absorbed by oxygenated hemoglobin (arterial) and one absorbed by de-oxygenated hemoglobin (venous). The results are compared to expected parameters and the pulse oximeter shows %(SaO2). Most also display heart rate, those with a graphic display also show an waveform that corresponds to arterial blood flow. So, pulse oximetry monitors multiple parameters - (SaO2), heart rate, the waveform is evidence of blood flow, and indirect evidence of cardiac rhythm. Normal values should be above 95%, which corresponds to a partial pressure of oxygen of 80 mmHg.
question
What approximate volume of oxygen does an E tank contain when the pressure gauge reads 2200 psi? (A) 2200 L (B) 880 L (C) 6600 L (D) 3400 L (E) 660 L
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Answer is E: A full E tank contains oxygen at a pressure of approximately 2200 psi. The volume in liters can be calculated by multiplying the psi by 0.3. (2200x0.3=660) The volume of oxygen in an H tank is approximately 3 times the psi. So, at a psi of 2200, there would be approximately 6600 L of oxygen in an H tank. These calculations are helpful to remember when calculating whe
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Which anesthetic breathing system has the highest fresh gas flow rate during maintenance of anesthesia? (A) Partial rebreathing (B) Closed system (C) Nonrebreathing (D) Semi-closed system
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Answer is C: In NONrebreathing systems, there is NO remixing of inhaled and exhaled gasses. These systems run at HIGH fresh gas flow rates, 100-300 ml/kg/min. A closed anesthetic rebreathing system only provides enough fresh gas flow to meet an animal's metabolic needs, about 5-10 ml/kg/min (depending on animal size. Flow is lower for larger animals and higher for smaller animals). Semi-closed and partial rebreathing systems are the same thing. They run at intermediate flow rates where fresh gas is delivered in excess of metabolic consumption, from about 10 ml/kg/min (large animals) or 30 ml/kg/min (small animals)
question
Which of the following choices are best for treating a patient that survives cardiac arrest but continues to have a persistent and unstable ventricular tachycardia? (A) Calcium gluconate or sodium bicarbonate (B) Lidocaine or mexilitine (C) Amiodarone or magnesium sulfate (D) 5% Dextrose or hypertonic saline solution
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Answer is C: Amiodarone or magnesium sulfate are preferred for treatment of persistent ventricular tachycardia following cardiac arrest. Lidocaine is sometimes used, however, amiodarone is associated with better outcomes. Mexilitine is an oral medication that is not used in these patients. It is used in dogs with ventricular arrhythmias caused by cardiomyopathy. Download this free issue of the Journal of Vet Emergency and Critical Care with CPCR guidelines for animals
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Which drug can reverse the effects of xylazine (alpha2-adrenergic agonist with analgesic and sedative effects)? (A) Yohimbine (B) Atropine (C) Diazepam (Valium®) (D) Pralidoxime
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Answer is A: Yohimbine is the reversal agent for xylazine. Remember "X goes with Y and Y goes with Z". Xylazine is reversed by Yohimbine. Yohimbine is also an antidote for amitraZ, the drug used to treat generalized demodicosis. Remember 2 things about xylazine: 1. Cattle are EXTREMELY SENSITIVE. Cow xylazine dose is about 20 times LESS than dogs or horses 2. Xylazine is used as an EMETIC in CATS, causes vomiting. Pralidoxime is used to treat organophosphate toxicity, along with a sedative for seizures, diazepam (Valium ®) or pentobarbital) and Atropine.
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Which of the following choices is a side effect that you should be aware of when using ketamine for anesthesia in cats?: (A) Dose-dependent respiratory depression (B) Cardiac arrest (C) Eyes stay open (D) Laryngospasm
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Answer is C: Ketamine and tiletamine are dissociative anesthetics often used as a part of the pre-med to immobilize cats prior to catheter placement or induction of general anesthesia. A cat's EYES stay OPEN with ketamine/tiletamine, so the corneas must be protected - an eye ointment like Lacri-lube should be instilled into both eyes. Remember cats ARE vulnerable to laryngospasm if you touch the larynx too much/too roughly during intubation for gas anesthesia. Spray with lidocaine topical anesthetic to prevent laryngospasm
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Which commonly-used anesthetic circuit is made up of a tube within a tube? (A) Universal Y circuit (B) Closed circle system (C) Bain system (D) Semi-closed circle system
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Answer is C: A Bain system is a tube within a tube. New oxygen and anesthetic gas is inhaled down the inner tube, and exhaled gas exits through the outer tube. (Note there is a modified form of a circular system called a "universal F circuit" that is also a tube inside a tube). A Bain anesthetic circuit run at a high flow rate of 200-300 ml/kg/min will not allow rebreathing of exhaled gasses. At lower flow rates (ie: 130-200 ml/kg/min or less) the Bain circuit functions as a PARTIAL rebreathing system, and the animal rebreathes some of the exhaled gasses.
question
When inducing anesthesia with barbiturates like thiopental or methohexital, premedication with atropine will prevent one of these side effects. Which side effect is prevented? (A) Slow heart rate (B) Fast heart rate (C) Slow breathing (D) Rapid breathing
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Answer is A: Anti-cholinergics like atropine or glycopyrrolate are given as pre-meds to INCREASE heart rate, DECREASE salivation and DECREASE airway secretions. Remember that many anesthetic drugs (like opiates, barbiturates, gas anesthetics) promote bradycardia (slowed heart rate) and some dissociative anesthetics (like ketamine, tiletamine) cause excessive salivation.
question
A 12-year-old Warmblood mare has been sedated intravenously with a combination of xylazine and butorphanol for dental evaluation because she has been dropping feed. You listen to the heart immediately after sedation and note a heart rate of 20 beats per minute [Normal = 28-44 bpm] with an occasional "dropped" beat; the horse is standing quietly. What is the most appropriate action to take next? (A) Prepare a dose of naloxone to reverse the butorphanol (B) Nothing; this is a normal response (C) Prepare a dose of yohimbine to reverse the xylazine (D) Prepare a dose of atropine to increase heart rate (E) Prepare a dose of dobutamine to improve cardiac contractility
answer
Answer is B: Nothing; this is a normal response. Bradycardia commonly occurs immediately after induction of sedation with alpha-two agonists, such as xylazine, in horses. This bradycardia is sometimes accompanied by transient second degree atrioventricular block and a decreased respiratory rate. Atropine is an antimuscarinic agent that increases the heart rate. It is rarely indicated in these cases and is associated with an increased risk of colic. Butorphanol is a mixed opioid kappa agonist-mu antagonist and may uncommonly cause bradycardia. Opioid reversal with naloxone would not be indicated because the butorphanol is not likely the cause of the bradycardia. In addition, reversal of a mixed agonist-antagonist is not complete. The effects of the alpha-2 agonists can be reversed with yohimbine, tolazoline, or atipamezole. This is unnecessary when the horse is standing quietly with a heart rate of 20 bpm and second degree atrioventricular block. Dobutamine is a beta-one agonist and increases cardiac contractility with little effect on the heart rate.
question
What is the effect of a high flow rate (200-300 ml/kg/min) when you are using a Bain nonrebreathing anesthetic circuit? (A) No effect on the amount of rebreathing of expired gases (B) Decreases the amount of oxygen that is used (C) Prevents rebreathing of expired gases (D) Increase the amount of rebreathing of expired gases
answer
Answer is C: A Bain anesthetic circuit run at a high flow rate of 200-300 ml/kg/min will not allow rebreathing of exhaled gasses. Remember that a Bain system is like a tube within a tube. New oxygen and anesthetic gas is inhaled down the inner tube, and exhaled gas exits through the outer tube. At lower flow rates (ie: 130-200 ml/kg/min or less) the Bain circuit functions as a PARTIAL rebreathing system, and the animal rebreathes some of the exhaled gasses.
question
The corneal reflex may be absent during what stage of general anesthesia? (A) Stage II, plane II (B) Stage 1, plane I (C) Stage IV (D) Early stage III
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Answer is C: The corneal reflex may be absent during Stage IV, which is an overdose of anesthesia-the patient will be very close to death. The corneal reflex should NEVER be gone if the patient is at an appropriate depth of anesthesia, unless the patient is paralyzed with a neuromuscular blocker. The corneal reflex does not always disappear, in fact, it is still present for a short time after death in some patients. It is not wise to use the corneal reflex routinely to determine anesthetic depth as it could be damaged with frequent touch. Also, it is often not available in dogs and cats since the eyeball rolls ventrally. Other reflexes and signs of anesthetic depth are quite reliable - palpebral response, eye position, tearing, nystagmus, etc. Note - there are no planes of anesthesia in stages I or II.
question
A 3 day old quarterhorse foal is anesthetized for a cerebrospinal fluid (CSF) tap, joint lavage and removal of an infected umbilicus. Just as the doctor begins the CSF tap, the heart rhythm becomes irregular, as seen on this electrocardiogram. The foal appears deeply anesthetized, but blood pressure and heart rate are normal. Which of the following correctly identifies this arrhythmia? (A) Atrial premature contractions (B) Ventricular escape beats (C) Left bundle branch block (D) Premature ventricular contractions
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Answer is B: There are 2 premature ventricular contractions (PVCs) on this ECG. There is no p wave, the R-R interval before each PVC is shorter than normal, and the QRS-T is 'wide and bizarre' in shape. PVCs seen under anesthesia are caused by hypercarbia, deep or light anesthesia, some anesthetic drugs, electrolyte abnormalities, hypoxemia, cardiac disease, and increased sympathetic tone. Inhalant anesthetics sensitize the myocardium to arrhythmias, and suppress ventilation. The vaporizer setting was decreased, mechanical ventilation was instituted, the PVCs disappeared and did not return. Click this link to see the ECG with legend. Follow this link to an excellent website - Interpretation of ECGs from UPenn.
question
What color is an oxygen tank supposed to be in the U.S.? (A) White or green (B) Blue (C) Yellow (D) Red or brown
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Answer is A: No matter what color the tank is, ALWAYS read the tag or label on the tank first to verify the gas contents inside. One instructor in Surgical Nursing and Anesthesia has reported seeing of a green tank containing carbon dioxide instead of oxygen! That being said, oxygen tanks in the U.S are typically white or green. Nitrous oxide tanks, (laughing gas) are blue. (Try remembering-"Laughing gas chases the blues") STRATEGY HINT: This is an "inclusion" question. That is, the choices "White or green" and " Red or brown" each INCLUDE more possibilities of being correct than the single-color choices of blue or yellow. If you were completely lost and had nothing else to go on, you might increase your chances of guessing right by choosing between the two inclusive choices of "White or green" and " Red or brown". This WILL NOT guarantee you always get a question right, but if you are lost, use whatever you can, including strategies like this.
question
What is the difference between heart rate and pulse rate? (A) No difference between pulse rate and heart rate in a sick animal (B) There are 2 heart beats for every pulse beat (C) Heartbeats per minute vs. palpable arterial waves per minute (D) Pulse rate is arterial pressure over time, vs. heartbeats per hour
answer
Answer is D: Although the terms are frequently used interchangeably, they describe slightly different processes. Heart rate is the number of beats of a heart per minute, while pulse rate is the number of palpable or visible arterial waves per minute. The counts of each will usually be identical, but illness, high blood pressure and other conditions can make these differ. Click here for a chart of resting heart rates of common domestic animals.
question
Which of the following patients is most likely to develop central sensitization of the pain response? (A) Dog with fractures following hit by car (B) Flank laceration in a horse (C) Flank laceration in a horseFeline castration (D) Dewclaw removal in a puppy
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Answer is A: A dog with fractures after being hit by a car is most likely to develop central sensitization of the pain response, also called wind-up. This develops when afferent neurons in the spinal cord are bombarded by impulses from an area with severe pain. The high number of afferent stimuli cause the spinal cord neurons to over-react (in a way) by opening more excitatory channels that amplifies the pain response further. If pain is not treated adequately, chronic and neuropathic pain results, as neurons that normally would not respond to painful stimuli actually change and begin to do so (allodynia). They also continue to respond when the pain stimulus lessens or is gone, such that the nervous system itself becomes the origin of the pain impulses. Any patient that suffers a painful insult can develop sensitization of the pain response. It occurs both locally and centrally. If treated appropriately, however, few develop chronic pain once the painful area is well.
question
What is the function of a pressure regulator in an anesthetic gas breathing circuit? (A) Absorbs CO2 vapor from exhaled gasses (B) Increases pressure of gas entering anesthetic machin (C) Reduces pressure of gas entering anesthetic machine (D) Bypasses vaporizer with fresh oxygen
answer
Answer is C: The pressure regulator DECREASES the pressure of gas (usually oxygen) leaving the pressurized gas cylinder. At lower pressure, the gas then flows through the flowmeter, (which controls the amount of carrier gas flow) then the vaporizer (where anesthetic vapor mixes) and then into the breathing circuit where the animal inhales the mix. Exhaled gasses pass through a CO2 scavenger canister and are then recycled, or are disposed of completely (non-rebreathing system). STRATEGY HINT: This is another kind of "frequency" question. That is, you can see how the choice "reduces pressure" and the "increases pressure" choice are flip sides of the same possibility. (Kind of like being repeated). Chances are that the correct choice will include the choice that is repeated the most often. In this case, even if you have no idea what the right answer may be, simply narrowing down to the two answer choices will increase your chances of picking correctly to 50:50
question
A horse is treated for pain and possible ileus with flunixin meglumine and a continuous infusion of lidocaine following surgical correction of a small intestinal volvulus. After about an hour, the horse at first seems sleepy, then begins twitching, shaking, and becomes ataxic. Which of the following is the most likely explanation of this scenario? (A) A severe systemic inflammatory response is underway (B) Anaphylaxis to the flunixin or another medication is developing (C) Hypocalcemia is common with colic; tremors are seen when calcium is low (D) These are signs of lidocaine toxicity
answer
Answer is D: Sedation, twitching, shaking, and ataxia are signs of lidocaine toxicity in horses. Intravenous (IV) lidocaine infusions are used often in horses following colic surgery to prevent ileus and/or encourage the return of intestinal motility. Sick horses can develop toxic signs with usual doses as they may not eliminate it as readily as healthy horses. Fortunately, it can be restarted later at a slower rate. Toxicity is also more likely when administered via gravity flow (counting drops), especially if piggy-backed onto other fluid lines. The actual rate varies with head position, hydration, and the speed/volume of other fluids given concurrently. Toxicity is less likely when infusion pumps are used, as the rate is more precisely controlled. Excellent pdf on colic including Lidocaine: Colic Treatment and Post-Colic Nutrition Dr. Nat White, courtesy the library at Kentucky Equine Research, www.ker.com
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Which one of the following is the most correct explanation of how electrical defibrillation works in patients with cardiac arrest? (A) Abnormal myocardial cells that are fibrillating are cauterized (B) Shock re-starts all myocardial cells at once, eliminating the unorganized rhythm and poor contractility seen with fibrillation (C) Shock stops all cells in heart simultaneously. Allows pacemaker cells to regain control of myocardial contraction (D) Shock accentuates strength of depolarization wave generated by pacemaker cells. They overwhelm fibrillation waves and restart cardiac rhythm
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Answer is C: Defibrillation is performed with electrical shock to stop the activity of all myocardial cells at once. Essentially, the heart is put into asystole, to allow the pacemaker cells to regain control of the cardiac rhythm. Pacemaker cells can produce an effective depolarization and contraction only when the myocardial cells are able to respond. They must not be actively contracting (or fibrillating) or in a refractory period. Click here to download Vet Emergency and Critical Care with CPCR guidelines for animals.
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A snake needs to be anesthetized to collect some skin biopsies. What anesthetic protocol would most commonly be used for this relatively non-invasive procedure? (A) Propofol (B) Guaifenesin (C) Xylazine (D) Ketamine (E) Isoflurane
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Answer is D: Ketamine and tiletamine are often used to anesthetize snakes for non-painful procedures. These anesthetics do not likely provide adequate visceral analgesia in snakes, so inhalant anesthesia would be recommended for more invasive, possibly painful, procedures
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Which of the following blood pressure measurements most closely corresponds to tissue blood flow? (A) Mean arterial pressure (B) Peripheral pulse pressure (C) Systolic arterial pressure (D) Central venous pressure
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Answer is A: The mean arterial pressure is the average pressure found in the arterial system and thus corresponds most closely to tissue blood flow and perfusion. It is the most important blood pressure parameter to monitor in anesthetized and critical care patients. The diastolic pressure is important to coronary perfusion because blood flow into the cardiac vessels occurs primarily between contractions during diastole. Systolic pressure is important when hypertension is present. Pulse pressure is the systolic minus diastolic pressure and determines the strength of the pulse. When PP is low, the pulse feels weak, when it is high, it feels very strong or bounding.
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Which one of the following choices correctly compares the effects of caudal vs. lumbosacral placement of an epidural nerve block using lidocaine in a ruminant? (A) Cattle remain standing with a caudal epidural but not lumbosacral (B) The perineum is desensitized with a caudal epidural but not lumbosacral (C) Overinserted needles cannot puncture the dura mater with a lumbosacral epidural (D) Analgesia of the vulva is better with a caudal epidural (E) Respiratory paralysis occurs more frequently with a caudal epidural than with lumbosacral
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Answer is A: attle remain standing with a caudal epidural but not a lumbosacral epidural using a local anesthetic. The femoral and sciatic nerves originate from spinal segments from L3 to S2. The lumbosacral space is located between vertebral bodies L6 and S1 in ruminants. Paralysis of the rearlegs will therefore be a major effect of a lumbosacral nerve block. Caudal epidurals are performed between Co1 and Co2 or between the sacrum and Co1. Performed correctly, the tail, rectum, anus, vulva, vagina, perineum, urethra, and the bladder will be affected. Click to see an excellent article on Local anesthesia by Lyon Lee DVM, PhD.
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Which of the following is the correct explanation of the mechanism of action of epinephrine when it is used during cardiopulmonary cerebral resuscitation (CPCR)? (A) Activate cardiac receptors in the myocardium (B) Increase coronary circulation via peripheral vasoconstriction (C) Stimulate respiratory centers in the brain (D) Stimulate respiratory centers in the brainImprove cardiac contractility
answer
Answer is B: Increase coronary circulation via peripheral vasoconstriction. Epinephrine causes intense peripheral vasoconstriction via its effect on alpha adrenergic receptors. This promotes a shift of the blood volume back to the heart which increases aortic and coronary blood flow. There is no way to directly 'restart' an arrested heart. Cardiac contractions resume when oxygen delivery is restored and energy production is adequate, Vasopressin also produces peripheral vasoconstriction via activation of V1 receptors on vasculature. It is often used in addition to or instead of epinephrine during CPCR. Download a free issue of the Journal of Vet Emergency and Critical Care with CPCR guidelines for animals
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Which of the following opioids provides good analgesia of long duration for mild to moderate pain in cats and can be given intravenously, intramuscularly, and subcutaneously as well as transmucosally? (A) Morphine (B) Oxymorphone (C) Buprenorphine (D) Methadone
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Answer is C: Buprenorphine is one of the most popular and reliable opioid analgesics for use in cats. Cats are quite difficult to evaluate for pain; many studies of analgesic drugs have shown equivocal or variable result. However, buprenorphine has consistently provided good analgesia for cats with mild to moderate pain. It should not be used in patients with severe pain. Since it is a partial mu-agonist, it does not cause many of the side effects of pure mu-agonists such as nausea, vomiting, and dysphoria. Duration is long, 6 hours or more; onset is also long, 30 minutes to an hour in dogs and cats, depending on the route of administration. It is difficult to reverse as it binds very tightly to the mu-receptor. Buprenorphine can be given transmucosally with almost 100% absorption as the pH of the cat's mouth (8-9) favors this. It is also available as a transdermal patch for humans, but so far these have not been effective for use in cats. Excellent review of pain in cats: SA Robertson. Managing Pain in Feline Patients. Vet Clinics of NA: SA Practice 2008; 38: 1267-9
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During recovery from anesthesia, a horse begins to have rapid nystagmus and paddle its limbs. What does this indicate? (A) Post-anesthetic myopathy (B) Hypoventilation (C) Trying to get up too soon (D) Hypotension (E) Hypoxemia
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Answer is C: Rapid nystagmus accompanied by paddling of the limbs typically indicates that the horse is about to try to get up prematurely. This would lead to a rough recovery and possible injury. Horses progress back through the stages and planes of anesthesia during anesthetic recovery. They often develop nystagmus. This horse should be administered a small amount of sedative (e.g., 50-100 mg xylazine IV).
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Which of the following medications would be the most appropriate choice to treat an animal with neuropathic pain, such as a dog with a lick granuloma? (A) Gabapentin (B) Acepromazine (C) Tramadol (D) Xylazine (E) XylazineLidocaine
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Answer is A: Gabapentin is an anticonvulsant that reduces neuropathic pain and central sensitization. Neuropathic pain is caused by damage to the peripheral or central nervous system, rather than regular stimulation of pain receptors.
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Which of the following is commonly seen during Stage III, plane 4 of general anesthesia? (A) Miotic pupil (B) Hypertension (C) Abdominal respirations (D) Hyperemic mucous membranes
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Answer is C: Respiration becomes completely abdominal in Stage III, plane 4 and stops in Stage IV. Stage IV is an overdose of anesthesia -the patient will be very close to death. Abdominal respiration means that only the diaphragm is working, the intercostal muscles of the chest are not. So the abdomen is seen moving in and out as the diaphragm contracts up and down, respectively. The respiratory rate and tidal volume will be decreased, eyes will be central, and pupils very dilated. Blood pressure and heart rate eventually also decrease. The inhalant anesthetic should be turned off immediately to decrease anesthetic depth, and the patient ventilated with 100% oxygen.
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Which drug is best for fast anesthetic induction in a very fat schnauzer? (A) Pentobarbital (B) Thiopental (C) Methohexital (D) Phenobarbital
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Answer is C: Really fat animals and sighthounds (like greyhounds, afghans) have trouble excreting barbiturates like the 4 choices here. Methohexital is a better choice for both because it does not absorb into fat and quickly induces anesthesia. (McCurnin & Bassert note alternatively could use propofol in sight hounds). Beware of RESPIRATORY DEPRESSION with barbiturates. Thiopental is an ultra-short-acting barbiturate that CAN be stored in fat and slowly released. Think of euthanasia with PENTObarb. Think of PHENObarb to control epilepsy/seizures.
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When using a reservoir bag during anesthesia with a rebreathing system, approximately how full should it be at peak expiration? (A) Three-quarters full (B) One-third full (C) Reservoir bags are not used in rebreathing systems (D) Half full (E) Completely full
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Answer is A: eservoir bags should be approximately three-quarters full at peak expiration. Reservoir bags, or rebreathing bags, are storage reservoirs for anesthetic gases breathed in and out by the patient in a rebreathing system. The volume in the bag is affected by the oxygen flow, the scavenging system adjustment, and the pop-off valve adjustment.
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Which anesthetic circuit does not allow mixing of inhaled and exhaled gasses? (A) Semi-closed circuit (B) Bain circuit at 200-300 ml/kg/min (C) To and fro system (D) Circle rebreathing circuit (E) Closed circuit
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Answer is B: A Bain anesthetic circuit running at a high flow rate of 200-300 ml/kg/min will not allow rebreathing of exhaled gasses. Remember that a Bain system is like a tube within a tube. New oxygen and anesthetic gas is inhaled down the inner tube, and exhaled gas exits through the outer tube. At lower flow rates (ie: 130-200 ml/kg/min or less) the Bain functions as a PARTIAL rebreathing system, and the animal rebreathes some of the exhaled gasses. The other 3 systems are RE-breathing systems. They are closed or semi-closed, meaning they only give as much oxygen and gas as the animal metabolically needs for anesthesia. Closed systems run at MUCH LOWER flow rates around 2-10 ml/kg/min. Semi-closed systems run at around 10 ml/kg/min (lg animals) or 30 ml/kg/min (small animals)
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Which one of the following anesthetic agents should be avoided for induction in a patient with head trauma? (A) Propofol (B) Etomidate (C) Alfaxalone (D) Thiopental (E) Ketamine
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Answer is E: Ketamine is not recommended for routine use in patients with head trauma because it INCREASES intracranial pressure (ICP). Head trauma patients may have edema or hemorrhage of brain tissue, and may already have an increase in ICP.
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Which of the following is the most detailed method for evaluation of acute pain in small animals? (A) Pre-emptive Scoring System (PESS) (B) Colorado State University Pain Scale (C) Visual Analog Scale (VAS) (D) Health-Related Quality of Life Scale (HRQLS)
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Answer is D: The Colorado State University Canine and Feline Acute Pain Scales include an assessment of behavior and includes the response to manipulation/handling of both the patient and the painful area. The VAS is a semi-objective scoring systems that primarily evaluates the intensity of pain in a patient. It utilizes a linear numerical scale and may miss patients that are actually in pain. The PESS is a subjective protocol based on an estimate of the pain expected from a particular procedure rather than evaluation of the patient. The HRQLS is for patients in chronic pain. Many pain scales/scoring systems exist.
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Which anesthetic breathing system has the lowest fresh gas flow rate during maintenance of anesthesia? (A) Partial rebreathing (B) Nonrebreathing (C) Closed system (D) Semi-closed system
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Answer is C: A closed anesthetic rebreathing system only provides enough fresh gas flow to meet an animal's metabolic needs, about 5-10 ml/kg/min (depending on animal size. Flow is lower for larger animals and higher for smaller animals). Semi-closed and partial rebreathing systems are the same thing. They run at intermediate flow rates where fresh gas is delivered in excess of metabolic consumption, from about 10 ml/kg/min (large animals) or 30 ml/kg/min (small animals). In nonrebreathing systems, there is NO remixing of inhaled and exhaled gasses. These systems run at HIGH fresh gas flow rates, 100-300 ml/kg/min.
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What fresh gas flow rate should you use during induction when using a semi-closed rebreathing anesthetic system in small animals? (A) 100 ml/kg/min (B) 5X the calculated maintenance flow (C) 200 ml/kg/min (D) 30-50 ml/kg/min
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Answer is A: The fresh gas flow rate during induction and recovery using a semi-closed rebreathing system is about 100 ml/kg/min, which is 2 to 3 times the calculated maintenance flow. During the maintenance of anesthesia, the flow is reduced to 30-50 ml/kg/min in small animals. The minimum flow rate is equal to the patient's metabolic oxygen requirement. Most use a higher flow rate as it is safer and requires less monitoring. Another consideration is the minimum setting required by the vaporizer, as some are not accurate at extremely low flows.
question
Nitrous oxide is sometimes used in conjunction with inhalant anesthesia but is contraindicated in which animal? (A) Cattle (B) Cats (C) Ferrets (D) Horses (E) Guinea pigs
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Answer is D: Horses. Nitrous oxide (N2O) is highly diffusible and accumulates in 'spaces' in the body. This causes distention of the intestines, which affects ventilation under anesthesia and may result in postoperative colic in horses. N2O is also not good to use in dogs undergoing intestinal surgery, especially a gastric dilatation-volvulus (GDV).
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Which of the following is the best explanation of why the base-apex attachment of leads is preferred over the limb lead attachment when performing an electrocardiogram (ECG) in a horse? (A) Equine purkinje fibers are deeply embedded, producing simultaneous ventricular contraction (B) Since the equine heart is so large, leads placed on the rear legs are too far away for a good recording (C) Horses don't tolerate the pinching on the stifles and elbows with attachment of limb leads (D) The ECG records surface electrical activity, therefore the leads must be very close to the heart
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Answer is A: Equine purkinje fibers are NOT located on the epicardial surface of the equine heart, they are very diffusely branched and embedded into the myocardium. This produces a simultaneous (almost) contraction of the ventricles. There is little or no difference in electrical activity on the equine ventricular surface, UNLIKE what is seen in small animals and humans. This results in a poor recording using ECG limb leads in horses. But when ECG leads are placed above and below the heart (base-apex), you can record a large difference, with excellent waveforms. The ECG records differences in surface electrical activity between the areas where electrodes are attached. Since the ECG recording is made over time, a waveform is produced (QRS, for example
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What is the difference between heart rate and pulse rate? (A) There are 2 heart beats for every pulse beat (B) No difference between pulse rate and heart rate in a sick animal (C) Pulse rate is arterial pressure over time, vs. heartbeats per hour (D) Heartbeats per minute vs. palpable arterial waves per minute
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Answer is D: Although the terms are frequently used interchangeably, they describe slightly different processes. Heart rate is the number of beats of a heart per minute, while pulse rate is the number of palpable or visible arterial waves per minute. The counts of each will usually be identical, but illness, high blood pressure and other conditions can make these differ. Click here for a chart of resting heart rates of common domestic animals.
question
High solubility means the gas is absorbed into the body tissues the most, causing slow anesthetic induction and slow recovery. Methoxyflurane has a very high solubility in the blood which associated with slow inductions and recoveries. In fact, we generally do not use methoxyflurane in large animals because induction and recovery is so slow. (A) Sevoflurane (B) Isoflurane (C) Methoxyflurane (D) Halothane
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Answer is C: High solubility means the gas is absorbed into the body tissues the most, causing slow anesthetic induction and slow recovery. Methoxyflurane has a very high solubility in the blood which associated with slow inductions and recoveries. In fact, we generally do not use methoxyflurane in large animals because induction and recovery is so slow.
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Which one of the following cases would NOT have visceral pain? (A) Pancreatitis (B) Large colon displacement (C) Testicular torsion (D) Abdominal laceration (E) Ureterolith
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Answer is D: An abdominal laceration does not produce visceral pain. This results from damage to abdominal organs or viscera, eg, liver, spleen, kidney, bladder, intestine. Sensory innervation for the viscera is carried by pain fibers included in sympathetic and parasympathetic pathways. Somatic nerves carry information from other areas including the skin, muscles, bones, etc. The viscera are not highly innervated with pain fibers, so many types of pain are not perceived. For example, cutting or suturing the intestine during a laparotomy is not painful. However, distention, mesenteric tension, and inflammatory or ischemic stimuli are very painful, as seen in patients with intestinal displacement/torsion, peritonitis, hemoabdomen, liver torsion, urethral obstruction, etc. Visceral pain responds much better to kappa opioid agonists rather than mu agonists because of the distribution of receptors. Butorphanol is often used in horses with colic, especially in combination with an alpha-2 agonist.
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A 50 lb mixed breed dog is heavily sedated with dexmedetomine and butorphanol given intravenously for repair of a laceration. His mucous membranes are pale, capillary refill time is 2 seconds, heart rate is 56 beats per minute [N=70-120 bpm], respiratory rate is 10 breaths per minute [N=18-34 brpm]. Which of the following is the next best step? (A) No treatment is necessary, this is normal with alpha 2 agonists (B) Place an intravenous catheter and bolus 10 ml/kg of lactated ringers (C) Give an anti-cholinergic intramuscularly for the slow heart rate (D) Perform an electrocardiogram to determine the type of bradycardia
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Answer is A: Bradycardia is a very common side effect of alpha-2 agonists in all species. It is a reflex, a baroreceptor response to the initial hypertension that is caused by intense vasoconstriction. The hypertension causes a reflex increase in vagal tone, which slows the heart rate. In this case, the low HR should not automatically be treated, as this would further increase BP and the workload of the heart. If the HR gets too slow or very dysrrhythmic, or BP drops too low, reversal with atipamezole is indicated. Refs: McCurnin's Clin Textbk for Vet Techs, 8th ed. pp. 1082-3, 1104, Thomas & Lerche Vet Anes and Analgesia for Vet Techs, 4th ed. pp 62-4 and the Merck Veterinary Manual online edition.
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Which anesthetic breathing system is the worst choice when using nitrous oxide? (A) Bain nonrebreathing (B) Closed rebreathing (C) Semi-closed rebreathing (D) Nonrebreathing
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Answer is B: Oxygen depletion and nitrous oxide buildup are common problems in a closed rebreathing system, so you should NOT use nitrous oxide with a closed system. Because higher gas flow rates are used with semi-closed and nonrebreathing systems, nitrous oxide (N20) buildup is less of a concern.
question
A flank laparotomy is performed in a cow following a distal paravertebral nerve block performed at the ends of transverse processes of L2, L3, and L4. As the veterinarian cut to the bottom of the skin incision, the cow becomes restless and begins kicking in the stocks. Which of the following is the most likely problem? (A) Cow has a low pain threshold, she needs sedation (B) Excitement and pain are making the cow restless (C) T13 nerve was not blocked (D) Prep time was too long or duration of action of local anesthetic is too short
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Answer is C: The T13 nerve was not blocked using the locations described above. T13 innervates the cranioventral aspect of the flank. It is blocked above and below the end of the transverse process of the L1 vertebrae. The other nerves blocked for a standing flank laparotomy are L1 and L2. These are blocked above and below the transverse processes of L2, and L4, respectively. The nerves are not blocked at their respective lumbar vertebrae because they course caudally after exiting their spinal foramen. With the proximal paravertebral block, local anesthetic is placed in the space just caudal to the transverse process of the same vertebrae as the nerve, behind T13, L1, and L2. The other possibility is that the dorsal branch of the T13 nerve was incompletely blocked. The nerves divide into a dorsal and ventral branch that provide sensory and motor innervation, respectively. This site should be repeated or an inverted L line block can be performed to provide anesthesia to the area.
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Which choice indicates that the soda lime granules in a CO2 absorbent canister have become exhausted? (A) Crystals become hard and turn off-white (B) Color change from purple to pink, crystals become powder (C) Color changes to brown and liquid accumulates at the base of the canister (D) Color stays pink, regardless of CO2 exposure
answer
Answer is A: The purpose of a canister of soda lime granules is to absorb carbon dioxide from exhaled anesthetic gasses. Fresh absorbent crystals are white and can be crushed. But exhausted, saturated crystals become a distinct off-white color and are hard. Most granules contain a pH-sensitive dye that becomes visible as the absorbent granules become saturated. (The color itself is not so important as the color changing). A color change from white to purple or violet typically indicates that the CO2 scavenger granules have become saturated with CO2, but this color change does not always happen, and will dissipate after a few hours.
question
Which anesthetic breathing system has an intermediate fresh gas flow rate during maintenance of anesthesia? (ie: 10-30 ml/kg/min, not the highest, and not the lowest) (A) Bain system (B) Semi-closed system (C) Nonrebreathing system (D) Closed system
answer
Answer is B: Semi-closed and partial rebreathing systems are the same thing. They run at intermediate flow rates where fresh gas is delivered in excess of metabolic consumption, from about 10 ml/kg/min (large animals) or 30 ml/kg/min (small animals). A Bain system runs at HIGH fresh gas flow rates, 100-300 ml/kg/min. A Bain anesthetic circuit run at a high flow rate of 200-300 ml/kg/min will not allow rebreathing of exhaled gasses. Remember that a Bain system is like a tube within a tube. New oxygen and anesthetic gas is inhaled down the inner tube, and exhaled gas exits through the outer tube. At flow rates of 130-200 ml/kg/min or less the Bain functions as a partial rebreathing system, and the animal rebreathes some of the exhaled gasses, but this is still a substantially higher flow rate than is mentioned in the question. A closed anesthetic rebreathing system only provides enough fresh gas flow to meet an animal's metabolic needs, about 5-10 ml/kg/min (depending on animal size. Flow is lower for larger animals and higher for smaller animals).
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Which of the following choices are effects of acepromazine in dogs and cats? (A) Prevent vomiting, vasodilation (B) Anti-arrhythmic, hypertension (C) Muscle relaxation, analgesia (D) Increase blood pressure, sedation (E) Increase blood pressure, sedationSedation, piloerection
answer
Answer is A: Acepromazine is a phenothiazine that causes vasodilation and acts as an anti-emetic, sedative, muscle relaxant, and anti-arrhythmic. Acepromazine blocks peripheral alpha-1 receptors, which produces vasodilation and hypotension. Acepromazine also blocks dopamine receptors in the brain, which produces sedative, anti-emetic, and anti-arrhythmic effects, as well as causing muscle relaxation. It does NOT provide analgesia or cause vasoconstriction.
question
How long can local anesthesia with bupivicaine last? (A) 4-10 hours (B) 2-3 hours (C) 1-2 hours (D) 3-4 hours (E) Less than 1 hour
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Answer is A: Bupivicaine can last 4-10 hours. Bupivicaine is the most frequently used local anesthetic for oral surgery because it has a long duration of action. It takes approximately 4-20 minutes to reach full effect. Conversely, lidocaine takes effect in just 3-5 minutes but only lasts 1.5-2 hours.
question
Which of the following statements about etomidate is true? (A) It is inexpensive (B) IV injection can be painful and cause phlebitis (C) It should not be given to patients with heart disease (D) It provides good analgesia (E) It should not be administered to patients in shock
answer
Answer is B: IV injection of etomidate can be painful and can lead to phlebitis and hemolysis. Slow IV administration via a running fluid line can help minimize these risks. Etomidate is a short-acting imidazole-derivative sedative-hypnotic that is injected for anesthesia induction in dogs and cats. Etomidate is expensive. It causes good muscle relaxation but minimal analgesia. It has a wide margin of safety, causing minimal respiratory and cardiovascular effects. It is the agent of choice in patients with heart disease and shock. Refs: Bassert and Thomas, McCurnin's Clinical Textbook for Veterinary Technicians, 8th edition, pp. 1085-6 and Plumb's Veterinary Drug Handbook, 7th ed.
question
Which statement is most correct regarding the inhalant anesthetics isoflurane and sevoflurane, in relationship to halothane? (A) They produce slower inductions and recoveries (B) They have lower solubility. (C) They have lower MAC (Minimum Alveolar Concentration) values. (D) They have much higher vapor pressures.
answer
Answer is B: Sevoflurane and isoflurane have lower solubility than halothane. Solubility determines speed of anesthetic induction and recovery; therefore induction and recovery is slower with halothane than with sevoflurane or isoflurane. A gas with a very high solubility such as ether has an even slower induction and recovery. Desflurane, with its extremely low solubility, has the fastest induction and recovery.
question
A 6-year-old mixed breed dog is anesthetized for an exploratory laparotomy/splenic mass removal with isoflurane in oxygen. Anesthetic monitoring includes an electrocardiogram (ECG), direct arterial blood pressure, end tidal carbon dioxide levels, oxygen saturation, anesthetic gases, and temperature. A recording of the ECG and the arterial pressure waveform is shown in the image below Which one of the following choices is the correct pulse rate in this patient? (A) 160 (B) 80 (C) 135 (D) 320 (E) 40
answer
Answer is B: Correct: 80 beats per minute. This case is just one example of why it is important to palpate the pulse periodically during anesthesia, rather than just following the monitors. Click here to see an illustration of the answer. At a paper speed of 25 mm/second (= 5 big boxes per second), there are 16 depolarizations in a 6 second period. To calculate the rate, 60 sec/6 sec = 10 X 16 = 160 depolarizations per minute from this strip. However, the blood pressure (BP) wave shows that there were only 8 ventricular contractions that actually produced blood flow (a pulse) in the same 6 seconds. Therefore, the pulse rate is 60/6 = 10 X 8 = 80 contractions per minute in this patient. This patient has a pulse deficit caused by a cardiac arrhythmia - a premature ventricular contraction (PVC) follows each sinus beat, so this is ventricular bigeminy. There are "pairs" of each - each sinus beat/one PVC, hence a "bigeminy". Note that the PVCs do not generate enough cardiac output to produce a separate blood pressure waveform, hence the pulse deficit. The PVCs probably contribute a small amount of flow seen as the extra "bumps" on the bp waveform. The QRST seen in PVCs are often "wide and bizarre" and do not have a p wave. Also note the one early beat that looks a bit different, it is labelled "F", as it is a "fusion" beat. This is seen when a sinus depolarization and a PVC reach the ventricles at the same time, producing a waveform somewhere between that of the normal one and the PVC. Also note that the BP waves (the result of cardiac mechanical activity) occur a few milliseconds after the sinus depolarizations (electrical activity), as noted by the arrows on the above image. How does one discover a pulse deficit? Doppler sounds, pulse oximeter sound and waveform graphic, auscultation of the heart, and palpation of an artery will all differ with the rate reported/seen on the ECG. (the p waves on the sinus beats are hard to see on these strips, sorry, but they really are there!)
question
Which choice correctly lists the order in which gases pass through a typical circular anesthetic circuit? (A) Pressure regulator, vaporizer, patient, CO2 canister, flowmeter (B) Flowmeter, pressure regulator, vaporizer, patient, CO2 canister (C) Vaporizer, pressure regulator, flowmeter,CO2 canister, patient (D) Pressure regulator, flowmeter, vaporizer, patient, CO2 canister
answer
Answer is D: Pressure regulator, flowmeter, vaporizer, patient, CO2 canister. Carrier gas exits the high pressure tank through the pressure regulator, which DECREASES the gas pressure. It then flows through the flowmeter, which controls the amount of carrier gas flow, then the vaporizer, where anesthetic vapor is produced from the liquid. Both anesthetic vapor and carrier gas exit the vaporizer and flow into the breathing circuit where the animal inhales the mix. Exhaled gases pass through a CO2 scavenger canister and are then recycled in a circle system, or are disposed of completely in a non-rebreathing system. STRATEGY HINT: This is an ORDER question. If you already know that the CO2 canister is LAST in the order, you can narrow your choices down to 2, right away. When you see ordering questions, look for things you are pretty sure must go FIRST or LAST, and then work from those choices to fill in between.
question
Which statement is most correct regarding the inhalant anesthetics isoflurane and sevoflurane, in relationship to halothane? (A) They have lower MAC (Minimum Alveolar Concentration) values. (B) They have lower solubility. (C) They produce slower inductions and recoveries (D) They have much higher vapor pressures.
answer
Answer is B: Sevoflurane and isoflurane have lower solubility than halothane. Solubility determines speed of anesthetic induction and recovery; therefore induction and recovery is slower with halothane than with sevoflurane or isoflurane. A gas with a very high solubility such as ether has an even slower induction and recovery. Desflurane, with its extremely low solubility, has the fastest induction and recovery.
question
Which of the following statements is the most accurate regarding anesthetic monitoring in reptiles? (A) Ultrasonic Doppler devices are impractical for assessing heart or pulse rate (B) Pulse oximetry is useful for monitoring trends in arterial oxygen saturation (C) Most reptiles maintain a normal righting reflex even at a surgical plane of anesthesia (D) Snakes are the only type of reptile in which corneal and palpebral reflexes can be elicited (E) Indirect and direct blood pressure measurements have been shown to be well correlated
answer
Answer is B: Trends in arterial oxygen saturation measured by pulse oximetry can be useful for anesthetic monitoring in reptiles although the absolute values are not reliable. Pulse oximetry can be performed by using an esophageal or cloacal reflectance probe. Indirect and direct blood pressure measurements do not correlate well in reptiles. Doppler ultrasonography is very useful for assessing heart or pulse rate in reptiles. The probe can be placed directly over the heart in lizards. The shell interferes with placement of the probe over the heart in chelonians so instead the carotid artery can be probed in the thoracic inlet. A surgical plane of anesthesia usually results in loss of the righting reflex although this is reported to be less reliable in turtles and tortoises. Corneal and palpebral reflexes cannot be elicited in snakes because they do not have eyelids.
question
Which of the following choices is a common cause of the Cheyne-Stokes breathing pattern? (Fast breathing, then slowing down, then no breathing, then cycle starts again) (A) Pulmonary hypertension and emphysema (B) Light levels (phase I) of inhalant anesthesia (C) Severe metabolic acidosis, Diabetic ketoacidosis (D) Brain damage, Animal too deeply anesthetized (E) Hypovolemia and low intracranial pressure
answer
QUESTION D: Damage to respiratory centers of the brain can cause Cheyne-Stokes respiration. (Fast breathing, then slowing down, then no breathing, then cycle starts again). Cheyne-Stokes occurs with increased intracranial pressure, ischemia, or direct brain damage. Click here to see a diagram of Cheyne-Stokes respiration. Cheyne-Stokes respiration is a usually a bad sign - herniation of the brain may be imminent. Cheyne-Stokes is also seen in patients under anesthesia who are too deep, and is reported as a side effect of morphine in humans.
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How can the "sting" associated with injection in awake patients be mitigated when using local blocking agents (e.g., lidocaine, bupivicaine)? (A) Use lidocaine and bupivicaine together (B) Ensure needle is placed directly over nerve (C) Mix with equal volume sterile saline (D) Add sodium bicarbonate (E) Combine with diluted epinephrine
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Answer is D: The "sting" associated with injection of local blocking agents in awake patients can be mitigated by adding 0.1 mL of sodium bicarbonate per 10 mL of blocking agent. Sterile saline can be used to extend the volume of blocking agent in small patients. Diluted epinephrine (1:200000) mixed with lidocaine can help extend the duration of action of the lidocaine. It should NEVER be used in circumferential limb blocks. Lidocaine and bupivacaine are sometimes mixed to utilize lidocaine's rapid onset of action and bupivicaine's duration of action. Ref: Bassert and Thomas, McCurnin's Clinical Textbook for Veterinary Technicians, 8th edition, pp. 1055-7.
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When might epidural anesthesia be contraindicated in a cow with dystocia? (A) It should always be performed (B) Possible candidate for fetotomy (C) When planning vaginal delivery (D) If Caesarian-section is likely (E) If the fetus is alive
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Answer is C: Epidural anesthesia can be contraindicated in cases where vaginal delivery is the planned method of delivery because it means the cow will not be able to assist in delivering the calf. Epidural anesthesia helps minimize the pain caused by vaginal manipulation of a dystocia. However, sometimes the cow will become recumbent, which can be contraindicated when trying to pull a calf. It also reduces the force of uterine contractions so manipulation is easier to accomplish.
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Which one of the following choices is the correct mean arterial pressure in this patient? (A) 76 mmHg (B) 125 mmHg (C) 100 mmHg (D) 49 mmHg (E) 93 mmHg
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Answer is E: 93 mmHg Click here to see an illustration of the answer. Mean arterial pressure (MAP) is approximately 1/2 the area under the pulse pressure curve as measured from one heartbeat. It can be calculated (estimated) from the systolic (SAP) and diastolic arterial pressures (DAP) as follows: DAP plus 1/3 of the pulse pressure (SAP - DAP). The SAP is 125-127 mmHg and DAP is 76-78 mmHg in this horse (approximate). 77 + (126-77)/3 = 77 + 49/3 = 77 + 16 = 93 mmHg. The mean arterial blood pressure (MAP) is important as this is the "driving" pressure for tissue perfusion. A low MAP results in ischemia and organ damage if present too long. Note that MAP is actually closer to the DAP than the SAP as shown by the dotted red line on the graph shown in the answer. A low DAP has a great effect on the overall mean. The lower the DAP, the higher the systolic AP must be to compensate and bring the mean up to adequate levels. Hypotension is common in anesthetized horses and can result in myopathy. Muscle damage occurs in horses at pressures not low enough to produce damage to other organs. Myopathy can result in serious injury and difficulty standing during anesthetic recovery if not treated in a timely fashion. Note the dip in the BP waveform very close to the mean pressure line on the illustration of the answer. This is the "dicrotic notch" which is produced by changes in blood flow in the large vessels when the aortic valve closes.
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Which animal is more sensitive to atipamezole and should be given a decreased dose to reverse dexmedetomidine? (A) Pigs (B) Cats (C) Cows (D) Horses (E) Dogs
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Answer is B: Cats are more sensitive to atipamezole so the dose should be decreased. Atipamezole is an alpha-two antagonist used to reverse the effects of dexmedetomidine and is usually given in equal volume. Dexmedetomidine is used mostly in small animals and exotics for sedation. Atipamezole can cause vomiting, diarrhea, tachycardia, hypertension, and CNS stimulation.
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During induction of anesthesia, the vet asks you to place an endotracheal tube. How far in should the end of the tube go for proper access to the trachea? (A) Caudal to uvula (B) Between the tonsils (C) Just to the nasopharnyx (D) Between the vocal folds
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Answer is D: An endotracheal tube goes between the vocal folds of the trachea ("endo" equals "into" the trachea!). Typically you inflate the cuff around the end of the tube to seal the airway. Use UNcuffed tubes in ferrets and very small animals (puppies, kittens) to preserve a larger airway diameter and in birds. Birds have complete tracheal rings that make their trachea less compliant (flexible) when an endotracheal tube cuff is inflated.
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Why are gas anesthetics not recommended for induction of anesthesia in chelonians (turtles)? (A) They take infrequent breaths (B) They have prolonged clearance of inhalants (C) They are exquisitely sensitive to inhalants (D) It is difficult to place a mask (E) They are insensitive to inhalants
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Answer is A: Chelonians tend to have long periods between breaths, making induction of anesthesia via inhalants difficult. Therefore, anesthesia is usually induced with injectables and then endotracheal tubes are placed for maintenance of anesthesia.
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What is xylazine primarily used for in bovine anesthesia protocols?QUESTION (A) Sedation (B) Pre-operative pain control and prevents hypoxemia (C) Maintenance of anesthesia (D) Induction of anesthesia (E) Postoperative pain control
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Answer is A: Xylazine (and its more potent cousin, detomidine) are used as sedatives in cattle. Remember the cow dose is about 10-20 times LESS than dogs or horses. Bloat and hypoxemia are a concern when you use these drugs in cattle. Xylazine is reversed with yohimbine, atipamezole, or tolazoline.
