Chapter 12 – General and Local Anesthetics – Flashcards

Drugs that depress the CNS or Peripheral Nerves to produce diminution of consciousness, loss of responsiveness to sensory stimulation, or muscle relaxation. They reduce or eliminate pain by depressing nerve function in the CNS and/or PNS.

The state of reduced neurologic function. The loss of the ability to feel pain resulting from the administration of an anesthetic drug or other medical intervention. Two types General and Local.

A drug-induced state in which the CNS nerve impulses are altered to reduce pain and other sensations throughout the entire body. It normally involved complete loss of consciousness and depression of normal respiratory drive. Complete loss of consciousness, loss of body reflexes, elimination of pain through whole body, skeletal and smooth muscle paralysis including respiratory requiring mechanical ventilation to avoid brain damage.

A drug-induced state in which peripheral or spinal nerve impulses are altered to reduce or eliminate pain and other sensations in tissues innervated by these nerves. Elimination of pain sensation in the tissues innervated by the anesthetized nerves. --does not involve paralysis of respiratory functions.

The practice of using combinations of different drug classes rather than a single drug to produce anesthesia. The simultaneous (combination) use of both general anesthetics and adjuncts.

Most commonly used to induce anesthesia during a surgical procedure through the use of one or more drugs. Induce a state in which the CNS is altered to produce varying degrees of pain relief, depression of consciousness, skeletal muscles, reflex reduction. Can either be Inhalation or parenteral anesthetics.

Volatile liquids or gases that are vaporized with oxygen to induce anesthesia....Inhaled gas: nitrous oxide Inhaled volatile liquids: enflurane, halothane, isoflurane, methoxyflurane, and others.

given IV and are used for induction and/or maintenance of general anesthesia,induction of amnesia, and as adjuncts to inhalation-type anesthetics. (helper drugs by enhancing the main anesthetic) to sedate, reduce anxiety, and amnesia. (etomidate and propofol) (though some parenteral anesthertics are used solely for general anesthetics like propofol (diprovan), which is used as a gerneral anesthertic or sedative hypnotic depending on the dose. Ex: etomidate, ketamine, methohexital, propofol, thiamylal, thiopental.

Drugs used in combination with anathetic drugs to control the adverse effects of anesthetics or to help maintain the anesthetic state in the patient. Sedative-hypnotics: Barbiturates, Benzodiazepines, hydroxyzine, and promethazine Opioid Analgesics: fentanyl, sufentanil, meperedine, and morphine. Neuromuscular blocking drugs (NMBDs): Depolarizing Drugs (succinylcholine), Nondepolarizing drugs (pancuronium, d-tubocurarine, vecuronium) Anticholinergics: Atropine, glycopyrrolate, scopolamine, Anxiolytics: propofol, Antiemetics

The Overall effect of gerneral anesthesia is a progressive reduction of sensory and motor CNS functions, with sight going first, then taste, smell, and hearing, plus loss of consciousness. Cardiac and pulmonary are the last to be effected. (Reverse when coming out) All of these "losses" due to aesthesia become the stages of anesthesia. Varies according to drugs. "Overton-Meyer Theory, lipid solubility" Progressive depression of cerebral and spinal cord functions.

for general anesthesia = surgery, ECT (electroconvulsive Therapy for depression), to produce unconsciousness, skeletal muscular relaxation, and visceral smooth muscle relaxation. Rapid onset; quickly metabolized.

Vary according to dosage and drug used, sites primarily effected are heart, peripheral circulation, liver, kidneys, and respiratory tract. Myocardial depression is common. Malignant hyperthermia- uncommon, potentially fatal, happens with inhalation anesthesia and causes rapid increased temp, tachycardia, tachypnea, muscle rigidty. Can occur during or after general anesthesia or use of NMBC succinylcholine. Life threatening emergency. treated with cardiopulmonary support and dantrolene (skeletal muscle relaxant.)

A genetically linked major adverse reaction to general anesthesia characterized by a rapid rise in body temperature, as well as tachycardia, tachypnea, and sweating.

A theory that describes the relationship between the lipid solubility of anesthetic drugs and their potency.

A milder form of general anesthesia that causes partial or complete loss of consciousness but does not generally reduce normal respiratory drive. Also called Conscious sedation = doesn't cause complete loss of consciousness. Patients relax, reduce anxiety, but still maintain an open airway and respong to verbal commands....also have mild amnesia. More rapid recovery than general. Combination of an IV benzaodiazepine and an opiate analgesic. Used for daignostic procedure and minor surgeries that do not require deep anesthesia. Topical anesthesia may be applied too. Greater safety profile.

Reduce pain sensation at the level of peripheral nerves, AKA regional anesthetics, blocks nerve conduction to a certain area without loss of consciousness. Render a specific portion of the body insensitive to pain. Interfere with nerve impulses transmission to specific areas of the body. Can be either topical or parenteral. 2 types Ester and amide (both end in -caine) be alert to make sure giving the type that a patient can tolerate. Used for childbirth, dental procedures, suturing, and diagnostic procedures. Interfere with nerve conduction.

Local anesthesia induced by injection of an anesthetic drug near the spinal cord to anesthetize nerves that are distal to the site of injection. Two types intrathecal or epidural.Desired in dental procedures, suturing, and diagnostic procedures.

Spinal or intraspinal, infiltration, nerve block, or topical. Parental anesthetics : lidocaine, mepivacaine, procaine, tetracaine, and others.

Usually limited, spinal headache sometimes treated with a blood patch, which is an injection of small volume, 15 ml, of venouse blood from patient into the epidural space. Inadvertent intravascular injection occurs, excessive dose or rate of injection is given, slow metabolic breakdown occurs, and injection into highly vascular tissue occurs are all reasons that can make an adverse effect occur.

Prevent nerve transmission in skeletal (including respiratory) and smooth muscle leading to paralysis. used as adjuncts with general anesthesia. ****Be sure to ventilate prior to giving an NMBD**** Curar = poison, Mainly used in the OR to control breathing during surgery but also used for diagnostic tests like laryngoscopy, bronchoscopy. DO NOT cause sedation or pain relief. Pt may be paralyzed yet conscious. Depolarizing and nondepolarizing. Succinylcholine and Pancuronium are a couple.

Succinylcholine, works similarly to neurotransmitter ACh. Bind in place of ACh at the motor endplates of muscle nerves or neuromuscular junctions. competitive agonists. Metabolism is slower than ACh, so as long as succinylcholine is present, repolarization cannot occur. Phase 1 : (depolarizing phase) the muscles fasciculate (twitch). Eventually, after continued depolarization has occurred, muscles are no longer responsive to ACh released. Phase 2: muscle tone cannot be maintained, and the muscles becomes paralyzed. (desensitizing phase) Result: flaccid muscle paralysis. (d-tubocurarine) short acting used for endotracheal intubation. and used for diagnostic drugs for myasthenia gravis. ****Emergency ventilation equipment must be immediately available for use*****

Bind to ACh receptors at the neuromuscular junctions, where they block the ACh actions. called competitive antagonists. Membrane never depolarized. Therefore, muscle fibers are not stimulated, and skeletal muscle contraction does not occur. (vecuronium and pancuronium) Based on their duration there are short-acting (mivacurium), intermediate-acting (atracurium, vecuronium, rocuronium), and long-acting drugs (pancuronium, doxacurium). First sensation is typically muscle weakness, usually followed by a total flaccid muscle paralysis.

Few when used appropriately. hypotension, tachycardia. Effects vary according to site. Neostigmine is antidote for NMBD and are used to reverse effect.

Always Assess past history of surgeries and response to anesthesia. Assess past history, allergies, medications, use of alcohol, illicit drugs, opioids. Assessment is vital during pre, intra, and postoperative phases. This includes vital signs, Baseline lab work, ECG, O2 stats, ABCs (Airway, breathing, circulation) Monitor all body systems. Watch for sudden elevations in body temperature, which may indicate malignant hyperthermia. During recovery, monitor for cardiovascular depression, respiratory depression, and complications of anesthesia. Implement safety measures during recovery. Reorient patient to his or her surroundings, provide postoperative teaching about the surgical procedure and anesthesia. Teach the patient about postop turning, coughing, deep breathing.