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25 Cards in this Set
- Front
- Back
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What is the main sign that a patient is in stage III anesthesia?
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No response to painful stimuli
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What are the important signs that indicate a patient is under light anesthesia?
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Upon incision, BP and HR rise
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What are the important signs that indicate a patient is under deep anesthesia?
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Fall in BP, and rate and depth of spontaneous ventilation
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Ketamine
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Acts on NMDA receptors
-Maintains respiration and is a profound analgesic -Considered to be a dissociative anesthetic -Often patients will hallucinate under ketamine (will give them a benzo to keep this from happening) -Given for serial dressing changes for burns -Maintains blood pressure and heart rate over a short period of time (increased sympathetic output) |
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How do inhaled anesthetics work?
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Enhance inhibitory neurotransmission by potentiating the actions of GABA and glycine at GABA A and glycine receptors
Prolong the opening of ion channels--> prolonging the duration of the postsynaptic current |
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IV nonvolatile anesthetics
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Thiopental (barbiturate)
Propofol Etomidate Ketamine |
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Side effects of Etomidate
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myoclonus, adrenocortical suppression
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Side effects of Ketamine
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Elevates ICP (don't use it for people with head injuries)
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Inhaled volatile liquids
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Isoflurane
Sevoflurane Desflurane |
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Depth of anesthesia induced by an inhaled anesthetic depends primarily on the __________ of the anesthetics on the brain
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Partial pressure
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Rate of induction and recovery from anesthesia depends on the_______________ in the brain
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Rate of change of partial pressure
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Decreased blood:gas coefficient
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Faster induction and recover (e.g. nitrous oxide)
Low solubility = faster recovery lower solubility = higher partial pressure in blood = faster uptake in brain |
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Increased blood:gas coefficient
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Slower induction and recover (e.g. halothane)
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Oil:gas partition co-efficient
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Measure of lipid solubility
Lipid solubility correlates strongly with potency of the anesthetic Increased lipid solubility = more potent anesthetic (e.g. halothane) |
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MAC Value
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The minimum alveolar anesthetic concentration (% of inspired air) at which 50% of the patients do not respond to a surgical stimulus
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Low lipid solubility = _____ MAC = ______ potency
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Low lipid solubility = big MAC = low potency
ex. N2O |
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High lipid solubility = _____ MAC = ______ potency
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High lipid solubility = low MAC = high potency
ex. isoflurane and halothane (most potent) |
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1.3 MAC
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99% of patients will not move at surgical incision
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1.5 MAC
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50% of patients have blocked autonomic (adrenergic) response to incision
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2.0 MAC
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50% of patients will not move or cough to endotracheal intubation
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Factors that increase MAC
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Acute drugs (stimulants), chronic alcohol abuse, highest at 6 months of age*, hyperthermia, red hair
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Factors that decrease MAC
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IV anesthetics (propofol, barbas, BDZ, ketamine), opioids, N2O*, acute alcohol, local anesthetics, increasing age (elderly)*, hyponatremia, hypothermia, severe hypotension (50mmHg), pregnancy
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Malignant Hyperthermia
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Pharmacogenic hypermetabolic state of skeletal muscle induced in susceptible individuals by volatile anesthetics and/or succinylcholine (a depolarizing muscle relaxant)
-possibly by stress or alcohol -Autosomal dominant, susceptible individual Ca2+ channel defect -may be fatal if not treated with dantrolene (blocks Ca2+ release from skeletal muscle sarcoplasmic reticulum) |
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What is usually used for induction of anesthesia in the OR?
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IV anesthetics such as propofol or thiopental
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What is usually used for maintenance of anesthesia in the OR?
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Usually done with a mixture of nitrous oxide and halogenated hydrocarbons (e.g. isoflurane, sevoflurane, desflurane)
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