anesthesia cases 6, 7, and 8 – Flashcards
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64 year old male with cardiac disease is managed medically with aspirin, metoprolol, lisinopril, and simvastatin. Which of these medications should NOT be taken on the day of surgery? a. Aspirin b. Metoprolol c. Lisinopril d. Simvastatin e. All of the medications should be taken
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C. lisinopril ACE-inhibitors should usually be held on the day of surgery because they are associated with an increased incidence of refractory intraoperative hypotension. Any patient taking a beta-blocker prior to surgery should continue taking it perioperatively, including the day of surgery. Though there is some controversy concerning Aspirin, patients with a history of coronary artery stents should generally continue taking aspirin because of the risk of stent thrombosis. This must be balanced with the risk of bleeding, especially for intracranial or spinal surgery.
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A patient, who six months ago had a drug eluting stent placed in his right coronary artery, needs to be scheduled for an elective non-cardiac surgery. Which of the following is TRUE regarding the best management of such a patient? a. Aspirin should be stopped perioperatively b. Clopidogrel should be stopped perioperatively c. The surgery should proceed as soon as possible, continuing both aspirin and clopidogrel d. The surgery should be delayed if possible and aspirin and clopidogrel continued for at least one year prior to surgery. e. Aspirin and clopidogrel should be taken for at least 6 weeks following stent placement, and this patient can be operated on at any time since it has been six months.
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D. Patients who have had a drug eluting stent placed should wait at least a year prior to having an elective surgery, and should be on aspirin and clopidogrel (Plavix) during that time. Patients who have had a bare metal stent placed should wait at least 6 weeks before undergoing an elective procedure and should be on aspirin and clopidogrel during this time. For balloon angioplasty without stent placement, a patient should wait 2 weeks and be on aspirin and clopidogrel during this time. Aspirin should be continued perioperatively in any patient with a coronary artery stent regardless of how long ago it was placed (again, unless the surgery being done dictates it be stopped - spinal or intracranial surgery). Plavix should not be stopped perioperatively during the time periods listed above, even if the surgery is urgent/emergent and cannot be delayed (again, unless the surgery being done dictates it be stopped - spinal or intracranial surgery).
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patients who've had a drug eluting stent should wait how long prior to having an elective surgery and be on what drugs during that time period
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Patients who have had a drug eluting stent placed should wait at least a year prior to having an elective surgery, and should be on aspirin and clopidogrel (Plavix) during that time.
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patients who've had a bare metal stent should wait how long before undergoing an elective procedure and should be on what drugs during this time
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Patients who have had a bare metal stent placed should wait at least 6 weeks before undergoing an elective procedure and should be on aspirin and clopidogrel during this time.
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patients who've had balloon angioplasty without stent placement should wait how long before having elective surgery and should be on what drugs during this time
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For balloon angioplasty without stent placement, a patient should wait 2 weeks and be on aspirin and clopidogrel during this time.
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Question: Clinical predictors of increased perioperative cardiovascular risk include which of the following? a. Recent MI (within 7-30 days) b. Compensated heart failure c. Diabetes mellitis d. 3rd degree heart block e. Rhythm other than sinus f. All of the above
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All of the above are risk factors for increased perioperative cardiac risk based on the American College of Cardiology/American Heart Association guidelines. The list of risk factors also includes: acute MI (<7 days), decompensated CHF, severe valvular disease, previous MI by Q-wave on ECG or history, angina, renal insufficiency, ECG abnormality such as LVH or LBBB or ST/T-wave abnormality, history of stroke, and uncontrolled hypertension.
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what are cardiovascular risk factors to consider before procedure
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recent MI (within 7-30 days) and acute MI (<7 days) and previous MI by Q wave on ECG or history compensated heart failure and decompensated heart failure diabetes 3rd degree heart block non-sinus rhythm angina renal insufficiency ECG abnormality like LVH or LBBB or ST/T wave abnormality history of stroke uncontrolled HTN
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If 64 year old male with cardiac disease had recently been experiencing intermittent chest pain (that was similar in quality to chest pain he had experienced prior to his stents being placed) along with exertional chest pain what would be appropriate management in the perioperative period?
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the patient should have further cardiac evaluation with stress echo prior to surgery This patient is having symptoms concerning for angina. Given the patient's history it would be appropriate to further evaluate the patient's cardiovascular status prior to undergoing a surgical procedure that does not need to be done emergently. It is possible that he may have stenosis in his coronary arteries that require intervention. An ECG and chest X-ray might be appropriate as part of a pre-operative workup, but the patient will still require more specific testing to determine if there is cardiac pathology causing his chest pain. On the day of his operation, the patient should continue to take his aspirin and beta-blocker. An arterial line may be appropriate for hemodynamic monitoring given his cardiac history, but a more complete workup prior to the operation is indicated.
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Myocardial oxygen supply is dependent on which of the following factors? a. Diastolic blood pressure b. Hemoglobin content c. Diastolic filling time d. Left ventricular end diastolic pressure e. All of the above
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E. all of the above are determinants of myocardial oxygen supply Coronary blood flow occurs during diastole, and thus perfusion of the myocardium is dependent on both diastolic blood pressure and diastolic filling time. Myocardial blood flow is dependent on the driving pressure of blood (Diastolic blood pressure - Left ventricular end diastolic pressure). Hemoglobin content is one of the factors that affect the oxygen content of blood, which affects the oxygen supply to the heart.
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What is the patient's blood oxygen content if he has a hemoglobin concentration of 10 g/dL, and a PaO2 of 60 mmHg, and his O2 sat % is 90%? a. 9 mL/dL b. 12.5 mL/dL c. 14 mL/dL d. 16.5 mL/dL e. 19 mL/dL
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B. 12.5 ml/dL Oxygen content is calculated by the following equation: O2 Content = (1.39 x Hemoglobin x O2 Saturation) + (PaO2 x 0.003). As can be seen from this equation, hemoglobin content of blood is a very important determinant of total blood oxygen content. Unlike other tissues, the myocardium is close to maximally extracting oxygen from the blood delivered to it at baseline. Therefore the only way to increase O2 supply to the myocardium would be to increase blood flow. In a patient with significant coronary stenosis, myocardial demand can overcome supply, leading to ischemia.
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equation for oxygen content
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O2 Content = (1.39 x Hemoglobin x O2 Saturation) + (PaO2 x 0.003).
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Which of the following is NOT a factor determining myocardial oxygen demand? a. Heart rate b. Myocardial contractility c. Afterload d. Coronary blood flow
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D. coronary blood flow Coronary blood flow is a factor determining oxygen delivery to the myocardium. Heart rate, contractility, and afterload are the main factors determining myocardial oxygen demand.
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Changing which of the following will both increase myocardial oxygen supply and decrease myocardial oxygen demand? a. Decreasing heart rate b. Decreasing diastolic blood pressure c. Increasing systolic blood pressure d. Decreasing contractility
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decreasing heart rate Decreasing heart rate protects the myocardium by decreasing oxygen demand and increasing supply. This is one of the ways in which beta-blockers work. Decreasing heart rate decreases myocardial oxygen demand while also increasing the time the heart is in diastole, which is when the coronary arteries are perfused. Beta-blockers also decrease myocardial contractility by blocking the beta effects of circulating catecholamines on the myocardium, further decreasing oxygen demand. These points emphasize the importance of rate control in patients with potential tachyarrhythmias such as Afib or Aflutter with rapid ventricular response. Beta-blockers, calcium channel blockers, and other medications are frequently used for rate control. Controlling the heart rate in these patients creates a more favorable oxygen balance and protects the heart from ischemia.
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Which of the following is the most important question to ask a patient pre-operatively with coronary artery disease (or concern for potential coronary artery disease) regarding cardiac reserve? a. Smoking history b. Blood pressure range c. Exercise tolerance d. Compliance with medication regimen e. Family history
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c. exercise intolerance A patient's exercise tolerance is generally considered to be the best indicator of cardiac reserve. In the absence of lung disease, decreased exercise tolerance is likely an indicator of decreased cardiac reserve. If a patient is able to climb two or three flights of stairs without symptoms (either of chest pain or shortness of breath), the patient's cardiac reserve is probably adequate for surgery.
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Which of the following factors DO NOT influence the incidence of perioperative myocardial infarction? a. History of MI 5 months ago b. History of CABG (coronary artery bypass graft) c. Site of the surgery d. Duration of the surgery
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B. history of coronary artery bypass graft The risk of perioperative MI is increased by several factors. A history of an MI within 6 months of surgery increases incidence of perioperative MI. This risk does not stabilize until 6 months after the prior MI, and remains elevated compared to patients with no prior history of MI. The site and duration of surgery is another factor that may increase the risk of perioperative MI, with major vascular surgery placing patients at higher risk, and intra-thoracic and intra-abdominal surgery increasing the risk for MI if the surgical procedure takes more than 3 hours. Interestingly, prior CABG is in and of itself not a risk factor for perioperative MI.
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Suppose that during your pre-operative evaluation of this patient, he gave a history of a few recent episodes of 'passing out when doing yard work' and reported his last cardiology follow-up was about 6 years ago. Also assume you observed a systolic heart murmur at the right upper sternal border that sounded harsh and radiated to the carotid arteries. What would be an appropriated course of action for this patient? a. Obtain a pre-op EKG and chest X-ray and if there are no significant changes from previous, then proceed with surgery. b. Consult cardiology for an evaluation, specifically focusing on an echocardiogram prior to proceeding with surgery. c. Evaluate the patient with carotid Doppler prior to proceeding with surgery. d. Evaluate the patient's EKG and chest X-ray as well as a CBC, BMP, and Cardiac Troponin- proceed to surgery if these are all normal or unchanged from previous. e. If the patient is currently asymptomatic, then proceed with the operation.
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b. Consult cardiology for an evaluation, specifically focusing on an echocardiogram prior to proceeding with surgery. This history and physical examination is concerning for possible aortic stenosis. This patient would require a more thorough evaluation prior to undergoing an elective procedure. He may require cardiac intervention prior to undergoing a non-cardiac surgery. Echocardiography and an evaluation by a cardiologist would be appropriate. It is a good idea to evaluate the patient's EKG and CXR as well as pre-op lab work prior to surgery, but further information would still be needed to ensure he is optimally prepared for surgery. The patient may need evaluation of his carotids at some point given his history of vascular disease, but his cardiac issues take precedence. Also, the patient's history is more consistent with aortic stenosis than with carotid disease. Just because the patient is asymptomatic during a preoperative evaluation does not mean that he is optimized for surgery. Surgery can induce hemodynamic stress, and if the patient has significant valvular disease, it may lead to cardiac ischemia.
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Following induction and intubation, but prior to the start of the surgery, the patient is noted to have frequent PVC's on his EKG tracing. He has remained hemodynamically stable with HR 72 and BP 111/76. Which of the following is TRUE regarding this issue? a. Decreasing the inhaled Sevoflurane concentration from 1.5% to 0.7% would be expected to solve the problem. b. Lidocaine given IV at induction of anesthesia is likely the cause of the problem. c. Giving a small bolus of Esmolol IV is an appropriate intervention. d. The case should be cancelled and the patient woken up.
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c. Giving a small bolus of Esmolol IV is an appropriate intervention. The PVC's the patient is having is likely due to the sympathetic response that has occurred during laryngoscopy. The volatile inhaled anesthetic agent Halothane was known to cause PVC's and other arrhythmias, but Sevoflurane, Desflurane, and Isoflurane are not thought commonly associated with them. Increasing the depth (not decreasing it) of the patient's anesthetic would be a possible means of decreasing these ectopic beats by decreasing patient stimulation. Lidocaine would not be expected to cause this problem. Lidocaine is often given to treat ventricular tachycardia or PVC's. Esmolol is a beta-blocker and would block the sympathetic stimulation of the myocardium, decreasing the ectopic beats. Unless the patient was truly unstable hemodynamically or there was concern about progressing to an unstable rhythm, the case need not be cancelled. Simple ectopic beats or PVC's are not unusual and can usually be managed by controlling heart rate.
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The patient takes 50 Units of Insulin NPH each morning for blood glucose control. What would be the most appropriate choice for the perioperative management of his diabetes? a. Administer no insulin as long as his HbA1C is < 7 b. Administer no insulin and start Dextrose containing fluids pre-operatively to prevent hypoglycemia c. D5 ½ NS will be the IV fluids of choice for intraoperative maintenance d. Administer ½ of the patient's usual dose of insulin on the morning of surgery
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d. Administer ½ of the patient's usual dose of insulin on the morning of surgery A common strategy for managing a diabetic patient on the day of surgery is to have the patient take ¼ to ½ of his usual dose of AM insulin on the day of surgery. Then blood glucose should be checked pre-operatively, post-operatively, and intra-operatively for all but the shortest procedures. It is usually not necessary to start an infusion of dextrose containing fluids in these patients, because the stress response to surgery will cause an increase in blood glucose levels. Intraoperative management of blood glucose levels usually involves titration of insulin either by following a sliding scale or utilizing an Insulin drip to keep a patient's blood glucose less than 180 mg/dL. The common signs of hypoglycemia will be masked during anesthesia, so care must be taken to avoid over correction of a high glucose level.
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If the patient's diabetes regimen had instead been metformin and glipizide for blood glucose control instead of insulin, what would be the most appropriate management? a. Glipizide should be continued and metformin held the day prior to surgery b. Metformin should be continued and glipizide held the day prior to surgery c. Both metformin and glipizide should be held pre-operatively. d. Intraoperative glucose control is not as important in this situation as long as the oral medications are restarted post-operatively as soon as possible.
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c. Both metformin and glipizide should be held pre-operatively. Metformin and sulfonylureas (i.e. glipizide) should be stopped the day prior to surgery (some advocate stopping 24-48 hours pre-op) because they may have a long half live and may lead to hypoglycemia in a patient who has been NPO pre-operatively. Diabetic patients are often scheduled early in the day if possible in order to minimize NPO time, and thus minimize potential hypo-glycemia preoperatively. This patient's blood glucose should also be controlled in the perioperative period with insulin if necessary, and it would be prudent to check pre, post and intraoperative blood glucose levels on this patient.
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If the patient also had chronic renal insufficiency (patients with vascular disease in the heart often have vascular disease in the kidneys), which of the following drugs for neuromuscular blockade would be the best choice? a. Succinylcholine b. Cisatracurium c. Rocuronium d. Doxacurium e. Pancuronium
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B Cisatracurium would be the best choice for neuromuscular blockade in a patient with renal insufficiency. It is eliminated primarily through Hoffman elimination, and would continue to be predictably eliminated in a patient with renal disease. Doxacurium and pancuronium rely heavily on renal elimination and would not be good choices in the setting of renal disease. Rocuronium primarily undergoes hepatic elimination, but prolongation of action has been reported in severe renal disease. Succinylcholine may be used for neuromuscular blockade in patients with renal disease, but should be used cautiously since administration of this drug can cause an increase in serum Potassium levels. Provided that the patient's serum potassium is less than 5, succinylcholine is considered safe.
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Which of the following drugs should be used very carefully, if at all, in the presence of renal insufficiency? a. Remifentanil b. Propofol c. Sevoflurane d. Isoflurane e. Meperidine
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E. meperidine This question highlights the fact that caution should be used when administering drugs to patients in whom clearance of the drug may not be normal. Any of the above drugs could be used if used appropriately in this patient, but it might be better to avoid meperidine (Demerol). Meperidine is metabolized in the liver to normeperidine, a renally cleared metabolite. In a patient with renal insufficiency, normeperidine may accumulate, and increased levels of this metabolite have been associated with seizures. Morphine is another medication that is has hepatic metabolism and renal clearance. Accumulation of morphine metabolites may lead to respiratory depression. The pharmacokinetics of the other drugs listed are not significantly affected by impaired renal function.
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In this patient with coronary artery disease, when performing endotracheal intubation, which of the following are maneuvers likely to blunt cardiovascular stimulation? a. Administration of intravenous lidocaine b. Administration of topical tracheal lidocaine c. Administration of beta blockade d. Administration of opiates at induction e. All of the above f. None of the above
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E. all of the above All are potentially useful in blunting cardiovascular stimulation at the time of laryngoscopy and intubation. Limiting the amount of time taken for laryngoscopy and intubation would also be beneficial. Laryngoscopy and intubation can be one of the most stimulating and stressful times for a patient undergoing surgery, and in a patient with cardiovascular disease, it is particularly important to minimize unnecessary alterations in heart rate and blood pressure.
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Intra-operatively, following a very stimulating portion of the surgical procedure, the patient's heart rate increases to the 95 (from its baseline of 73) while his blood pressure is 107/71 (it was 128/82 pre-operatively). His O2 sat is 95%. ST segment depressions are noted in Leads II and V5 on the patient's ECG tracing. Which of the following interventions would NOT be appropriate for this patient's management? a. Esmolol IV b. Fentanyl IV c. Discontinue Nitrous Oxide to give 100% O2, while increasing Sevoflurane from 1.3% to 2%. d. Phenylephrine IV e. All of the above are appropriate
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d. Phenylephrine IV Phenylephrine, an alpha agonist, will increase SVR, increasing afterload, and potentially worsening myocardial ischemia by increasing myocardial work. Based on the scenario given, the ischemic changes in the patient's EKG are most likely related to the increase in heart rate, which in turn is most likely related to the patient responding to surgical stimulation. Improving the myocardial supply/demand relationship to a more favorable balance can treat the ischemia. This can be accomplished by increasing the inhaled oxygen concentration, deepening the anesthetic to reduce patient response to a stimulus, and slowing the heart rate with a beta-blocker.
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In the same patient, 15 minutes after your interventions, the patient's EKG has returned to baseline. At the end of the case the patient is hemodynamically stable and his EKG appears the same as it did pre-operatively. What is the BEST next step in management for the patient? a. Obtain a 12-Lead EKG and cardiac enzymes in the PACU. b. The patient should remain intubated and be transferred to the ICU c. The patient should be taken for cardiac catheterization as soon as possible d. The patient should be brought to the PACU on a diltiazem drip for rate control
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a. Obtain a 12-Lead EKG and cardiac enzymes in the PACU. A patient who has experienced intraoperative ST changes on EKG warrants some cardiac workup, and an EKG and cardiac enzymes are a good place to start. It is possible that the patient may end up needing cardiac catheterization, but since he is hemodynamically stable, jumping to that intervention without initial evaluation is unnecessary. Since the patient is hemodynamically stable and was breathing spontaneously without any issues preoperatively, he likely can be extubated. Had he remained unstable, or required continuous inotropic support, then an ICU admission would be a consideration. This patient had sinus tachycardia, which by history was likely due to response to surgical stimulation, and his EKG returned to baseline. Therefore a diltiazem drip for rate control would not likely be needed. Had he instead had atrial fibrillation or flutter with rapid ventricular rate, then rate control with a drip, such as esmolol, diltiazem, or even amiodarone might be appropriate.
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The patient was brought to the ER in a c-collar because of concern about cervical spine injury. Which of the following is true regarding intubation of this patient? a. Rapid sequence induction would be appropriate. b. Taking the patient to the OR prior to intubation would not be a viable option. c. The patient must remain in the c-collar while being intubated. d. It would not be appropriate to use fentanyl prior to intubation of this patient because of concern for possible hypotension e. Using an awake fiberoptic intubation technique would prevent any potential increase in intracranial pressure during the intubation process
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a. Rapid sequence induction would be appropriate. Since the patient's NPO status is not known, it must be assumed that the patient has a full stomach. In some trauma situations, it may be possible to take the patient to the OR prior to intubation, and this may be the best option if the patient continues to breathe on his own and protecting his airway. It must be recognized that there can be injuries to the face or airway that may make direct laryngoscopy difficult or impossible. Provided that the cervical spine is stabilized during the intubation process, it is possible to remove the c-collar from a patient with concern for cervical spine injury. This may allow better mouth opening and visualization. An assistant should stabilize the cervical spine while laryngoscopy takes place. After intubation the c-collar may be replaced. If there is concern about increased intracranial pressure, it may be a good idea to treat the patient with medications such as fentanyl to blunt the increase in intracranial pressure that can occur with intubation. Performing a fiber optic intubation does not decrease the risk of increased intracranial pressure during intubation.
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Which of the following is true regarding rapid sequence induction? a. Preoxygenation is not possible since the patient should not be mask ventilated. b. Fentanyl or alfentanil should never be given prior to induction. c. Mask ventilation after an induction dose of propofol or etomidate may be needed to keep O2 saturation up prior to neuromuscular blockade. d. Inhalational induction may be used as the induction method for a rapid sequence induction. e. Cricoid pressure should be held throughout the induction process and continued until endotracheal tube placement within the trachea is confirmed.
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e. Cricoid pressure should be held throughout the induction process and continued until endotracheal tube placement within the trachea is confirmed. fentanyl or alfentanil can be used prior to intubation to blunt patient response to direct laryngoscopy. opioids should be used cautiously in patient whose respiratory status is already depressed inhaled induction is not an option for rapid sequence induction, but pre-oxygenation is important. if patient is breathing on his own having him breath 100% oxygen via facemask for 3-5 min prior to induction will increase the amount of time before the patient begins to desatruate after apnea has been induced. this is important because with RSI the patient should not be mask ventilated after induction as there is a risk of distending the stomach with air, possibly causing the patient to vomit. The most commonly used muscle relaxant for RSI is succinylcholine due to its rapid onset and short duration of action. Recall the extensive side effect profile discussed in earlier cases. One of the adverse side effects of succinylcholine is that it may cause acute hyperkalemia in patients with extensive denervation injury (such as spinal cord injury). This is also a possible response in patients with extensive burns or major trauma such as crush injuries. Succinylcholine may be used within the first 24 hours without increased risk, but after that time if rapid sequence intubation is needed, rocuronium would be a better choice for neuromuscular blockade in patients with such injuries.
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why is cricoid pressure helpful during rapid sequence intubation
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The use of cricoid pressure theoretically prevents reflux and aspiration of gastric contents during induction by preventing the ability of gastric contents to reach pass the upper esophagus. It should be continued until proper placement of the ETT is confirmed.
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why is fentanyl or alfentanil used prior to induction
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in order to blunt the patient's response to direct laryngoscopy
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why shouldn't a patient with rapid sequence intubation not be mask ventilated after induction
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risk of distending stomach with air and causing patient to vomit
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the most commonly used muscle relaxant for rapid sequence intubation is
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succinylcholine due to its rapid onset and short duration of action One of the adverse side effects of succinylcholine is that it may cause acute hyperkalemia in patients with extensive denervation injury (such as spinal cord injury). This is also a possible response in patients with extensive burns or major trauma such as crush injuries. Succinylcholine may be used within the first 24 hours without increased risk, but after that time if rapid sequence intubation is needed, rocuronium would be a better choice for neuromuscular blockade in patients with such injuries.
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Question: If the patient was brought to the emergency room by EMS without IV or IO access, and the patient's vitals were BP 84/43 and HR 126, what would be the most appropriate next step in resuscitation after the establishment of dependable IV access? a. Bolus epinephrine 1mg IV to treat hypotension b. IV beta-blocker to treat heart rate c. Lactated Ringers 2 liters IV d. D5 ½ NS 2 liters IV, followed by maintenance IV fluid rate based on the patient's weight with D5 ½ NS e. 1 Unit of Whole Blood (O-negative) IV f. Albumin 500 mL IV
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c. Lactated Ringers 2 liters IV This patient's history and vital signs depict shock secondary to hypovolemia. ATLS guidelines dictate that 2 liters of isotonic crystalloid should be the initial resuscitation for all trauma patients. Early and aggressive fluid management is important and associated with improved outcomes. Lactated Ringers is the preferred crystalloid for resuscitation in trauma as opposed to Normal Saline. If the patient has continuing or worsening shock despite resuscitation with crystalloid, blood product administration should be considered. If the patient's blood type is not known, then Type O-negative PRBC's would be the initial blood product of choice.
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If this patient opens his eyes only to pain, withdraws to painful stimuli, and is saying some words but they are inappropriate and not answers to questions, then what would be his GCS? a. 5 b. 6 c. 7 d. 8 e. 9
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The patient's GCS would be 9. He would get a 2 for eye opening, a 3 for verbal, and a 4 for motor response. The Glasgow Coma Scale is commonly used to evaluate the level of consciousness. It assesses three broad categories: the opening of the eyes, verbal response, and motor response. No overlap between subcategories exists. It is very reproducible and can be repeated at different time intervals to monitor either improvement or decline of the patient.
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what score is given in the glasgow coma scale if their eyes are never open
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1
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what score is given in the glasgow coma scale if their eyes open to pain
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2
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what score is given in the glasgow coma scale if their eyes open to verbal stimuli
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3
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what score is given in the glasgow coma scale if their eyes open spontaneously
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4
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what score is given in the glasgow coma scale if there is no verbal response
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1
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what score is given in the glasgow coma scale if there is incomprehensible sounds
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2
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what score is given in the glasgow coma scale if there is verbal response but only inappropriate words
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3
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what score is given in the glasgow coma scale if the patient is disoriented but converses
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4
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what score is given in the glasgow coma scale is given if the patient is oriented and converses
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5
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what score is given in the glasgow coma scale is given if there is no motor response
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1
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what score is given in the glasgow coma scale is given if the patient can extend (decerebrate rigidity)
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2
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what score is given in the glasgow coma scale is given if the patient can flex (decorticate rigidity)
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3
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what score is given in the glasgow coma scale is given if the patient does flexion withdrawal
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4
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what score is given in the glasgow coma scale is given if the patient can localize pain
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5
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what score is given in the glasgow coma scale is given if the patient obeys motor commands
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6
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patients with a glasgow scale of ___________ or less by definition are in coma and these patients require intubation for airway protection
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8
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On imaging the patient is found to have a depressed skull fracture and a subdural hematoma that require operative management. Which of the following would NOT be an appropriate induction agent for this patient? a. Propofol b. Etomidate c. Thiopental d. Ketamine e. Midazolam f. None of the above
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D. ketamine This patient is at risk for increased intracranial pressure (ICP). Ketamine would not be an appropriate drug for induction of anesthesia in this patient because ketamine causes an increase in intracranial pressure. The other agents listed can be used without increasing ICP. Ketamine may still be used in a patient with increased ICP if that patient is also hemodynamically unstable.
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If instead of suffering a head injury due to a motorcycle accident, the patient had suffered gunshot wounds to the abdomen, which of the following would not be an appropriate agent for induction? a. Propofol b. Etomidate c. Thiopental d. Ketamine e. Any of the above could be used
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e. Any of the above could be used Any of the above agents could be used. Depending on the clinical presentation of the patient some agents would be better than others. If the patient was hypotensive and there was concern for acute or ongoing blood loss, ketamine or etomidate may be better choices since these agents do not cause vasodilatation or cardiac depression. Propofol and thiopental may cause hypotension and if the patient is already hypotensive they may be best avoided.
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In a patient who is hypotensive secondary to ongoing hemorrhage and in whom intracranial hypertension is also a concern, which of the following should be the most immediate action taken. a. The patient should be taken to the OR in order to surgically control hemorrhage. b. A CT scan of the head should be done to determine if the patient has increased intracranial pressure. c. Attempts should be made to contact the patient's family to obtain consent for surgery/procedures and obtain pertinent history. d. The patient should be taken to the ICU and stabilized prior to going to surgery.
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a. The patient should be taken to the OR in order to surgically control hemorrhage In a patient with hypotension due to ongoing hemorrhage who also has possible increased intracranial pressure (ICP), control of the hemorrhage is of vital importance. Ongoing hypotension will decrease the patient's cerebral perfusion pressure and potentially lead to ischemia in the affected area of the brain. If it is necessary to go to the OR to control the hemorrhage, waiting for imaging studies is not appropriate. In a patient with known increased ICP, who can be stabilized and taken to surgery at a later time this may be an option.
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Which of the following agents may be used for maintenance of anesthesia in a patient with head injury and increased intracranial pressure? a. Sevoflurane b. Isoflurane c. Remifentanil d. Propofol e. Nitrous Oxide f. All of the above
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F. all of the above Any of the listed anesthetic agents could be used, provided they are used appropriately. A total intravenous anesthetic (TIVA) with propofol and remifentanil would be an option. All of the intravenous agents except ketamine decrease cerebral metabolic rate and either have no change on intracranial pressure or decrease it (ketamine increases ICP). The inhaled anesthetic agents may be used as well. However, the volatile anesthetic agents used at high concentrations can abolish cerebral autoregulation while they increase cerebral blood flow. This may exacerbate ICP. When used at concentrations less than 1 MAC cerebral autoregulation remains largely intact. Hyperventilation to a PaCO2 < 35 may minimize the increase in cerebral blood flow seen with volatile agents.
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The patient is undergoing a craniotomy, and intraoperatively he becomes hypertensive. Which of the following is NOT a viable option for treatment of this hypertension? a. Deepening the patient's anesthetic by increasing the concentration of inhaled nitrous oxide from 25% to 50% b. Increasing the rate of propofol infusion c. Labetalol IV d. Nicardipine IV e. Increasing the amount of inhaled sevoflurane from 1% to 1.5%
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d. Nicardipine IV Direct-acting vasodilating drugs such as calcium channel blockers, nitroglycerin, nitroprusside, or hydralazine should not be used because these drugs increase cerebral blood flow and increase intracranial pressure, even though they cause a decrease in systemic blood pressure. The other choices listed would be viable options.
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In a patient with intracranial hypertension, which of the following ventilation strategies would be best employed intraoperatively and potentially continued postoperatively following surgery? a. Hyperventilation to a PaCO2 20-25 and PaO2 should be kept above 200. b. Hyperventilation to a PaCO2 of about 30-35 and PaO2 should be kept above 100 c. Normal ventilation with PaCO2 of about 40 and PaO2 of about 100 d. Hypoventilation with PaCO2 of about 45 and PaO2 under 100.
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b. Hyperventilation to a PaCO2 of about 30-35 and PaO2 should be kept above 100 Moderate hyperventilation is useful in reducing cerebral blood flow and thereby reducing ICP. In using this technique to lower intracranial pressure, the patient is usually hyperventilated to a PaCO2 of 30-35. Hyperventilation to an even lower PaCO2 (i.e. 20-25) could shift the patient's hemoglobin dissociation curve to the left and decrease oxygen delivery in addition to severely limiting cerebral blood flow. ICP also responds to O2 tension, but only to extremely low oxygen tensions, with a large increase in CBF (and potentially a large increase in ICP) when PaO2 approaches 50.
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How is cerebral perfusion pressure (CPP) calculated? a. CPP = Systolic BP - ICP b. CPP = (Systolic BP - Diastolic BP) - ICP c. CPP = MAP - (ICP or CVP, whichever is greater) d. CPP = MAP/CVP - ICP
answer
c. CPP = MAP - (ICP or CVP, whichever is greater) Cerebral perfusion pressure (CPP) is calculated as follows: CPP = Mean Arterial Pressure - (Intracranial Pressure or Central Venous Pressure, whichever is greater). Under normal circumstances CPP is primarily dependent on MAP because ICP is normally less than 10. Remember- Mean Arterial Blood Pressure can be calculated with the following equation- MAP= (systolic Pressure + 2xDiastolic Pressure)/3. As such, diastolic pressure is the most important component in the determination of mean arterial pressure.
question
Normal cerebral autoregulation maintains cerebral blood flow between a MAP of: a. 100-200 mmHg b. 50-100 mmHg c. 40-180 mmHg d. 60-160 mmHg
answer
d. 60-160 mmHg Under normal circumstances, cerebral autoregulation maintains cerebral blood flow between mean arterial pressures of 60 and 160. In patients with chronic hypertension, the cerebral autoregulation curve may be shifted to the right, meaning that regulation of cerebral blood flow may actually occur at a higher MAP. In these patients cerebral blood flow may be normal at a MAP of 180, and at a MAP of 60 cerebral blood flow could actually be inadequate. Other factors can disrupt cerebral autoregulation, either regionally within the brain or globally. These factors include ischemia, traumatic injury, brain tumors, and inhaled anesthetic agents at high doses. At concentrations of less than 1 MAC autoregulation is maintained, but higher concentrations abolish autoregulation, making CBF more directly proportional to MAP.
question
In a patient presenting with increased intracranial pressure, which of the following measures would be best to decrease ICP? a. Ventilate the patient with high levels of PEEP b. Nitroglycerine drip c. Keeping the patient in Trendelenburg position d. Mannitol e. All of the above may be employed
answer
d. Mannitol Medical management of increased intracranial pressure may include acetazolamide, furosemide, or mannitol. Vasodilators should be avoided. Patients with increased intracranial pressure may be kept in a head elevated position to help decrease pressure. Hyperventilation may be used to decrease intracranial pressure, but the effect will only decrease cerebral blood flow for the first 24 to 48 hours, as CSF bicarbonate levels will adjust to compensate for the lower pCO2. Ventilation with high levels of PEEP and high airway pressures are not recommended unless absolutely necessary because they may further increase ICP. External ventricular drain or even decompressive craniectomy may be required for management of increased ICP in some cases.
question
Which of the following interventions may be taken as the patient is emerging from anesthesia in order to prevent increases in intracranial pressure? a. Leaving the patient intubated and sedated b. Bolus of opioids at the end of the case c. Lidocaine bolus IV at the end of the case d. Labetalol given IV to manage hypertension e. All of the above
answer
e. All of the above All of the above are potential interventions that may be needed and should be considered at the end of a case when an increase in intracranial pressure could be detrimental to the patient. Lidocaine and/or opioid administration may help prevent coughing during extubation. Extubating the patient "deep" might also be considered, because this could help avoid coughing or straining by the patient in response to the endotracheal tube. However, if this extubation strategy is taken, it should be done very carefully to ensure that re-intubation will not be necessary.
question
If our patient was undergoing a craniotomy in the sitting position and became acutely hypotensive with an acute drop in end-tidal CO2 from 31 to 20, what would be the likely cause? a. Acute blood loss b. Migration of the endotracheal tube into the right mainstem bronchus c. Venous air embolism d. Myocardial infarction
answer
c. Venous air embolism This scenario is consistent with venous air embolism. Venous air embolism can occur any time the operative site is above the level of the heart, but is of particular concern during neurosurgery with the head elevated above heart level. The clinical signs of venous air embolism are typically a decrease in oxygen saturation and a decrease in end-tidal CO2, followed by hypotension. The changes in O2 sat and end-tidal CO2 occur because of an increase in pulmonary dead space. If the air embolism is large, hypotension may occur before hypoxemia is apparent. Cardiac dysrhythmias and a "mill wheel" murmur may be late signs of venous air embolism.
question
:Which of the following measures should be taken to treat venous air embolism? a. Nitrous oxide should be discontinued b. Irrigation of the operative site with fluid c. Compression of the internal jugular veins d. Placement of the patient in a head down position e. All of the above measures should be taken
answer
e. All of the above measures should be taken All of the above measures to treat venous air embolism should be taken. Placing the patient in a head down position and compressing the jugular veins should rapidly be performed as it may prevent future entrance of air into the circulation. Irrigation or flooding the surgical field should also be done to attempt to stop further entrainment of air. If nitrous oxide is being used as part of the anesthetic, it should be stopped immediately as it may potentially increase the size of the venous air embolus. Aggressive cardiovascular support should be initiated
question
Two days postoperatively the patient is in the ICU and is found to have a serum sodium level of 118 mEq/L. He appears to be euvolemic and is not requiring any inotropic or pressor support. What is the most likely cause of the patient's low sodium level? a. Diabetes insipidus b. SIADH c. Cerebral salt wasting d. Hyperalodosteronism
answer
b. SIADH This scenario is consistent with SIADH. Patients with head trauma may develop SIADH, cerebral salt wasting, or diabetes insipidus. DI would be characterized by an elevated sodium level rather than hyponatremia. SIADH and cerebral salt wasting may appear similar, but SIADH is typically seen in patients who are hyper or euvolemic and cerebral salt wasting is typically seen in patients who are hypovolemic. For definitive diagnosis of SIADH, urine sodium and osmolality may be checked. A urine osmolality of > 100 and a urine sodium > 40 is consistent with SIADH.
question
how can you distinguish between diabetes insipidus, SIADH, and cerebral salt wasting.
answer
DI would be characterized by an elevated sodium level rather than hyponatremia. SIADH and cerebral salt wasting may appear similar, but SIADH is typically seen in patients who are hyper or euvolemic and cerebral salt wasting is typically seen in patients who are hypovolemic. For definitive diagnosis of SIADH, urine sodium and osmolality may be checked. A urine osmolality of > 100 and a urine sodium > 40 is consistent with SIADH.
question
Two days postoperatively the patient is in the ICU and is found to have a serum sodium level of 118 mEq/L. He appears to be euvolemic and is not requiring any inotropic or pressor support. How should SIADH be treated in this patient if he is found to be lethargic and confused? a. Free water restriction b. 3% normal saline bolus to correct to 135 mEq/L c. IV vasopressin d. D5 1/2 normal saline at 2 times maintenance rate
answer
a. Free water restriction Generally hyponatremia should be corrected slowly, since rapid correction can lead to central pontine myelinolysis. Hyponatremia should not be corrected at a rate faster than 8 mmol/L in 24 hours. A patient's Sodium deficit can be calculated according to the formula: Na deficit = Total Body Water x (desired [Na] - actual [Na]). (Where total body water can be estimated as 0.6 x body weight in kg in a male or 0.5 x body weight in kg for a female.) The goal for correction initially is 130 mmol/L. If a patient is hypovolemic it may only be necessary to use normal saline to correct the deficit. If the patient is euvolemic it is more likely that 3% NS may be necessary, but correction should be slow. In either case, if SIADH is the underlying cause, restricting free water is a mainstay of treatment.
question
how can you calculate sodium deficit in a patient
answer
A patient's Sodium deficit can be calculated according to the formula: Na deficit = Total Body Water x (desired [Na] - actual [Na]). (Where total body water can be estimated as 0.6 x body weight in kg in a male or 0.5 x body weight in kg for a female.) The goal for correction initially is 130 mmol/L.
question
if a patient is hyponatremic and hypovolemic, what is treatment
answer
normal saline
question
if a patient is hyponatremic and euvolemic how do you treat
answer
3% normal saline
question
Which of the following are associated with end-stage renal failure? a. Anemia b. Decreased platelet adhesiveness c. Metabolic acidosis d. All of the above
answer
d. All of the above End stage renal disease is associated with several physiologic changes. Anemia is the result of decreased erythropoietin production, decreased red cell production, and decreased survival of the red blood cells. Platelet and white blood cell function are impaired as well as platelet adhesiveness and aggregation. These hematologic changes result in a decrease in oxygen carrying capacity, thus the cardiac output increases to compensate. Increased cardiac output, along with sodium retention cause an increase in systemic blood pressure which may result in left ventricular hypertrophy, congestive heart failure, and pulmonary edema. These patients also have multiple metabolic derangements including hyperkalemia, hyperphosphatemia, hypocalcemia, hypoalbuminemia, and metabolic acidosis.
question
Which of the following is an acute life threatening complication of diabetes? a. Hypertension b. Autonomic neuropathy c. Diastolic dysfunction d. Diabetic ketoacidosis
answer
D. diabetic ketoacidosis
question
what are the 3 acute life threatening complications of diabetes
answer
There are three acute life threatening complications of diabetes. These include diabetic ketoacidosis, hyperosmolar nonketotic coma, and hypoglycemia.
question
what causes diabetic ketoacidosis
answer
Diabetic ketoacidosis (DKA) is the result of the accumulation of ketone bodies from the catabolism of free fatty acids. This occurs with decreased insulin activity and results in an anion gap metabolic acidosis. The most common cause of DKA is infection.
question
what are symptoms of diabetic ketoacidosis
answer
Symptoms include tachypnea, nausea, abdominal pain, confusion, and emesis.
question
what is the treatment for diabetic ketoacidosis
answer
Therapy involves fluid resuscitation with monitoring of potassium level and correction of the hyperglycemia with insulin.
question
what causes hypoglycemia in diabetic patients
answer
Hypoglycemia in the diabetic patient is the result of excess insulin administration which can result in lightheadedness, confusion, seizures, and coma. Manifestations of hypoglycemia include tachycardia, diaphoresis, and nervousness, but these symptoms are difficult to appreciate in a patient under general anesthesia.
question
what is the treatment for hypoglycemia in diabetic patient
answer
The treatment of hypoglycemia is the administration of 50% glucose intravenously.
question
what are symptoms of hyperosmolar nonketotic coma
answer
In hyperosmolar nonketotic coma, a hyperglycemic dieresis causes dehydration and hyperosmolality. In the patient case, there is not enough insulin available for the formation of ketone bodies. This severe dehydration leads to renal failure, lactic acidosis, and intravascular thromboses. The elevated osmolality also results in altered mental status and seizures secondary to changes in the cerebral fluid balance. Treatment again focuses on fluid resuscitation with normal saline and electrolyte monitoring.
question
After an extensive discussion with the patient, it is decided that a regional anesthetic technique would be the best option for this patient. Upon what receptors do local anesthetics work? a. Mu receptors b. Kappa receptors c. Sodium ion channels d. NMDA receptors
answer
c. Sodium ion channels Local anesthetics inhibit sodium ion channels. During membrane depolarization of the nerve cell, voltage gated sodium channels open, and an influx of sodium ions occurs. This reverses the membrane potential from negative to positive, generating an action potential. Local anesthetics bind the α subunit within the cell blocking the transit of sodium and interferes with action potential generation and impulse conduction. Opioids bind to kappa, mu, delta, and sigma opioid receptors. These are G protein linked receptors and activation of these receptors inhibits nociceptive neurotransmission secondary to hyperpolarization of the cellular membranes. This hyperpolarization is thought to be secondary to increased permeability of the cell membranes to potassium and calcium. The inhibition of NMDA receptors is the mechanism of action of ketamine.
question
Which of the following is an amide local anesthetic? a. Cocaine b. Lidocaine c. Benzocaine d. Procaine
answer
b. Lidocaine Lidocaine is an amide local anesthetic. Other examples of amide local anesthetics are bupivacaine, etidocaine, mepivacaine, ropivacaine, prilocaine, and dibucaine. Amide local anesthetics have an amide link between the benzene ring and the intermediate chain, while ester anesthetics have an ester linkage. Amides are metabolized by the liver, and esters are metabolized by plasma cholinesterase. Metabolism of esters is more rapid than that of amides. Both types are renally excreted.
question
Which location of injection would have the greatest systemic absorption of the local anesthetic? a. Epidural b. Subcutaneous c. Brachial plexus d. Intercostal
answer
d. Intercostal The rate of systemic absorption of local anesthetics is greatest in areas of greatest vascularity (IV>tracheal>intercostals>caudal>paracervical>epidural>brachial plexus>sciatic>subcutaneous). Systemic absorption is decreased by the addition of vasoconstrictors such as epinephrine. Additionally local anesthetics that are highly protein bound have less systemic absorption.
question
list in order of decreasing rate of systemic absorption of local anesthetics: IV brachial plexus intercostals sciatic subcutaneous paracervical epidural tracheal caudal
answer
it's greatest in the areas of greatest vascularity: IV> tracheal > intercostals > caudal > paracervical > epidural > brachial plexus> sciatic>subcutaneous
question
Systemic absorption is decreased by the addition of
answer
vasoconstrictors such as epinephrine.
question
An axillary block is chosen as the best option for this patient's regional anesthetic. What nerves are identified for an axillary block? a. Ulnar, median, radial b. Radial, musculocutaneous, ulnar c. Ulnar, median, intercostobrachial d. Median cutaneous, ulnar, radial
answer
A. ulnar, median, radial The brachial plexus is made up of the anterior primary divisions of the nerve roots from C5-C8 and T1. The brachial plexus is divided into roots, trunks, divisions, cords, and terminal nerves. The main terminal branches are the radial, median, ulnar, musculocutaneous, and axillary nerves. The axillary nerve block involves identification and infusion of local anesthetic around the median, ulnar, and radial nerves. These nerves are identified by their location in relation to the axillary artery. The median nerve is directly above the artery, the radial nerve is posterior and inferior to the artery, and the ulnar nerve is below the artery.
question
where is the ulnar nerve relative to artery
answer
below
question
where is the radial nerve relative to the artery
answer
posterior and inferior
question
where is the median nerve in relation to the artery
answer
directly above
question
what areas are typically missed by an axillary block
answer
The areas typically missed by the axillary block are those innervated by the musculocutaneous, intercostobrachial, and median cutaneous nerves.
question
What is the maximum dose of lidocaine without epinephrine? a. 4.5 mg/kg b. 7 mg/kg c. 3 mg/kg d. 12 mg/kg
answer
A. 4.5 mg/kg The maximum dose of lidocaine and mepivacaine when given without epinephrine is 4.5 mg/kg.
question
when lidocaine is given with epinephrine what is the max dose of lidocaine
answer
When given with epinephrine the maximum of both of these anesthetics is 7 mg/kg.
question
what is the max dose of fcocaine, tetracaine, bupivacaine, and ropivacaine
answer
The maximum dose of cocaine, tetracaine, bupivacaine, and ropivacaine is 3 mg/kg,
question
what is the max dose of chloroprocaine
answer
and the maximum dose of chloroprocaine is 12 mg/kg.
question
what problems can arise from local anesthetic toxicity
answer
Local anesthetic toxicity can cause cardiac arrhythmias and conduction disturbances that can lead to cardiac arrest and death.
question
what are symptoms of local anesthetic toxicity
answer
Early symptoms of local anesthetic toxicity include perioral numbness, dizziness, tongue paresthesia, tinnitus, blurred vision, and restlessness. Later signs may include tonic-clonic seizures and respiratory arrest.
question
what increases risk local anesthetic toxicity
answer
Pregnancy, hypoxemia, and respiratory acidosis increase the patient's risk for toxicity.
question
Which of the following local anesthetics is considered to be most likely to cause cardiotoxicity? a. Ropivacaine b. Lidocaine c. Bupivacaine d. Chloroprocaine
answer
c. Bupivacaine The incidence of central nervous system toxicity caused by local anesthetics mirrors the potency of the local anesthetic. Bupivacaine is four times as potent as lidocaine and thus produces CNS toxicity at a lower plasma concentration. Ropivacaine is three times as potent as lidocaine. Cardiovascular toxicity of local anesthetic agents occurs at a higher blood level than CNS toxicity. Lidocaine CV toxicity occurs at 7x the level at which CNS toxicity occurs. Chloroprocaine cardiotoxicity occurs at 3.7x the dose at which CNS toxicity occurs, and bupivacaine and ropivacaine CV toxicity occurs at 2x the level at which CNS toxicity occurs. As bupivacaine is the most potent of the agents listed and has a lower concentration necessary for CV toxicity, bupivacaine is most likely of the listed agents to cause cardiotoxicity. In addition, because it has a greater effect on cardiac sodium channels and a slow dissociation from them, bupivacaine is particularly toxic to the heart.
question
what determines the potency of local anesthetics
answer
Potency of local anesthetics is related to their lipid solubility. Non-ionized, highly lipid soluble agents diffuse into the nerve fibers more effectively=more potent.
question
what determines duration of action of local anesthetics
answer
The duration of action of local anesthetics is related to their degree of protein binding. Anesthetics that are highly protein bound have a longer duration of action.
question
what is the treatment for cardiac toxicity from local anesthetics
answer
The treatment for cardiac toxicity from local anesthetics includes rapid initiation of ACLS, and 20% intralipid 1.5 mL/kg bolus followed by an infusion. The intralipid serves as a lipid reservoir for the highly lipid soluble bupivacaine, thus allowing it to accumulate away from the heart and CNS and slowly be metabolized from this lipid reservoir
question
The axillary nerves were poorly visualized and a supraclavicular block was performed instead of an axillary block. Shortly after the procedure, the patient experience shortness of breath. Which of the following would aid in the diagnosis of this patients problem? a. Lidocaine Level b. Chest X-ray c. CBC d. 20% Intralipid
answer
B. chest x-ray The incidence of pneumothorax following supraclavicular block is 0.5-0.6%, and the risk of phrenic nerve block is 40-60%. A chest x-ray will aid in the diagnosis of both a pneumothorax or a phrenic nerve block. Although shortness of breath can be a sign of anemia or local anesthetic toxicity, these diagnoses are much less likely.
question
supraclavicular blocks are contraindicated in which patients
answer
This block is relatively contraindicated in patients with poor pulmonary reserve or severe lung disease.
question
During the block, 30mL of 0.5% bupivacaine with 1:200000 epi is injected. How many mg of bupivacaine and epinephrine have been injected? a. 150 mg bupivacaine and 150 mcg epinephrine b. 150 mg bupivacaine and 50 mcg epinephrine c. 50 mg bupivacaine and 150 mcg epinephrine d. 50 mg bupivacaine and 150 mcg epinephrine
answer
a. 150 mg bupivacaine and 150 mcg epinephrine A 0.5% solution of local anesthetic contains 0.5 g/100ml or 5mg/1ml solution. Thus 30ml of solution would contain 150mg of bupivacaine. A 1:200,000 solution of epinephrine contains 1g epinephrine in 200,000ml solution, or 5mcg/ml. Thus 30ml of solution would contain 150mcg of epinephrine.
