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28 Cards in this Set
- Front
- Back
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Properties of a good anesthetic
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Anesthesia - reversible loss of sensation and consciousness
Analgesia - Reduction/prevention of pain perception. Amnesia - Loss of memory Akinesia - Loss of motor activity Minimal cardio-vasc depression Non-flammable Rapid induction and recovery. |
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MAC
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Minimal alveolar concentration. How potency of volatile anesthetics is measured. Is the alveolar partial pressure of a an agent which will prevent a muscle response to a noxious stimulus in 50% of patients.
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Factors that alter rate of induction
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1) Alveolar partial pressure
2) Blood:gas coefficient 3) Cardiac output 4) Blood flow distribution |
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What is the input of alvelar partial pressure dependent on?
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-Inspired partial pressure
-Alveolar ventillation rate -Anesthetic breathing circuit volume |
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What is the output of anesthetic from the alveoli dependent on?
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1) Blood gas coefficient
2) Cardiac Output 3) Alveolar to venous partial pressure difference |
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Stages of anesthesia
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1) Induction/Analgesia
2) Delerium/Excitation 3) Surgical anesthesia Plane 1 - occulomotor movement stops Plane 2 - Lose response to incision Plane 3 - Ideal surgical plane Plane 4 - Respiratory depression 4) Coma and Death |
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Blood:gas coefficient
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Amount of gas dissolved in blood vs not. If coefficient is high, it means more must be dissolved in blood before being passed to the brain tissue. This is because anesthetic transfer to the brain only begins after the blood has been fully saturated.
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How does one speed up induction with regards to inspired partial pressure, ventilatory rate, and soluability of agent
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Fast induction occurs with high inspired partial pressure, high ventilation rate, and low soluability of agent.
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How does blood:gas coefficient effect induction speed.
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Blood:gas coefficient is inversely related to induction speed because the higher the coefficient, the more gas that must be dissolved in the blood before the drug can be delivered to the brain.
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How is cardiac output related to speed of induction
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Higher Cardiac output will more rapidly remove anesthetic from alveoli resulting in slower induction (and vice versa).
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What factors determine the rate of recovery from anesthesia?
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Tissue concentration, alveolar ventilation, metabolic rate.
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Common side effects of volatile anesthetics
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-resp/cardio Depression
-Hypothermia -Nausea -Increased intracranial pressure |
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Halothane
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Highly potent Highly soluble
Slow induction SE - cardio/resp depression -arrhythmias -increased cerebral blood flow -can lead to hepatitis and malginant hyperthermia |
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Isoflurane
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Less soluble than halothane and enflurane
Rapid induction Is a muscle relaxant SE - Pungent odor Cardio/resp dperession -decreases vasc resistance -increases cranial blood flow -causes arrhythmias -can irritate bronchi |
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Enflurane
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Less soluble than halothane
Rapid induction Is a muscle relaxant SE - Cardio/resp dperession -decreases vasc resistance -increases cranial blood flow -causes arrhythmias -can irritate bronchi |
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Desflurane
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Muscle Relaxant
low solubility rapid induction SE - Mild reps/cardio depression -mild increase in cranial blood flow -irritates airways -Expensive |
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Sevoflurane
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Muscle Relaxant
low solubility rapid induction dosent irritate airways SE - Mild reps/cardio depression -mild increase in cranial blood flow -Expensive |
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Nitrous Oxide
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Weak anesthetic
Very Insoluable, Fast induction Potent analgesic SE - Inhibits B12 synth and methionine synthase. -increased intracranial pressure -replaces N2 in tissues |
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Xenon
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Extremely insoluble, Fast induction, no SE, only problem, extremely expensive.
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3 reasons why IV is chosen over gas
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1) One less barrier (alveoli) to overcome
2) Can shut off IV and bring patients back more quickly 3) Higher therapeutic index, not as easy to OD patient. |
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Propofol
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IV anesthetic
Rapid onset and recovery, short duration Weak analgesic Metabolized by liver SE - hypotension and brady arrhythmias -resp depression -histamine (rash) -painful injections Expensive |
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Etomidate
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IV anesthetic (GABA effect), Used for short procedures
Rapid induction/recovery Wide safety margin SE - Can get myoclonic movements -can cause nausea vomiting -suppresses cortisol -irritating when injected -siezures -reduce adrenocortical function |
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Ketamine
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IV dissasociative anesthetic (NMDA antagonist)
Amnesia, analgesia, and catalepsy (muscle rigidity) SE - Halucinations in adults -Carido stimulant - increases ICP -siezures -muscle rigidity -minimal resp depression |
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Barbiturates
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IV anesthetic adjunct, fascilitates GABA
-thiopental -thiamylal -methohexital Rapid onset and reovery Weak analgesic Low therepeutic index SE - cardio/resp depression -arrhythmias |
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Dexmedetomidine
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Adjunct anesthetic (alpha 2 agonist)
Sedation and analgesia but NO anesthesia Used for short procedures on near terminal patients SE - cardio depression -dry mouth nausea -poor amnesia |
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Analgesics
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-Fentanyl
-Sufentanil -Alfentanil -Meperidine -Morphine SE - cardio/resp depression and opiate effects |
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Tranquilizers
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Benzodiazepines such as midazolam and diazepam. Enhance induction of anesthetic
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Muscle relaxants
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Pancuronium, succinylcholine
Can facilitate intubation. SE - Bradycardia -Hyperkalemia -myalgia -malignant hyperthermia -treat with neostigmine or erdrophonium |
