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49 Cards in this Set
- Front
- Back
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Most common method of general anesthesia
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Combo of inhalational and I.V.
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How is regional anesthesia accomplished?
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Blockade of major nerves or plexuses
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What is the MAC?
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Minimum Alveolar Concentration
Concentration, @ 1 atm, that produces immobility in 50% of pts. |
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What variables cause an INCREASED MAC?
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Hyperthyroidism
Hyperthermia Alcoholism |
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What variables cause a DECREASED MAC?
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Hypothyroidism
Hypothermia Alcohol intoxication Increased age Sedatives |
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What is stage 1 of anesthesia?
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Analgesia
Interference w/ synaptic transmission in spinothalamic tract |
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What is stage 2 of anesthesia?
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Disinhibition, excitement, incontinence, vomiting
Blockade of inhibitory pathways |
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What is stage 3 of anesthesia?
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Unconsciousness, relaxation
Depression of ascending pathways in RAS |
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What is stage 4 of anesthesia?
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Cardiorespiratory depression
Depression of the vital medullary centers |
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What is the goal of anesthesia?
(w/ regards to stages) |
Make stage 2 as short as possible
Avoid stage 4 altogether |
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What is the Myer-Overton relationship?
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Oil/gas partition coefficient seems to correlate w/ potency
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What is the mechanism of halogenated ether inhaled anesthetics?
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Activate GABA-A receptors
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What is the mechanism of NO2 and Xe?
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Primarily inhibit NMDA glutamate receptors
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At what level is immobilization mediated?
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Spinal cord
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At what level is unconsciousness mediated?
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Cerebral
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What concentration is reached for virtually all inhaled anesthetics?
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70 nM
(w/ chemical properites of olive oil) |
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How does solubility relate to onset of inhaled anesthetics?
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Less solubility --> faster onset
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Rank of solubilities of inhaled anesthetics from least to most
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Desflurane, NO2 < Sevoflurane < Isoflurane < Halothane
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What is driving force for partitioning inhaled anesthetics in the body?
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Partial pressure
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What is the driving force of transport for inhaled anesthetics in the body?
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Tension
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How long does uptake last in the brain, kidney, heart, and viscera?
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5 - 15 minutes
(these areas get high flow per volume) |
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How do bones, cartilage, and ligament affect uptake?
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They have NO EFFECT
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How long does it take for fat to equilibrate?
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Fat has the highest anesthetic solubility
It NEVER equilibrates |
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What are the relative potencies of the inhaled anesthetics?
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ALL are similarly potent
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What are the side effects of inhaled anesthetics?
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Initial increase in respiratory rate, w/ decreased tidal volume
(Followed by a respiratory depression) Decreased response to hypercapnia or hypoxia Decreased BP |
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How does halothane affect BP?
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Decreased cardiac contractility
(SO, it does NOT increase HR) |
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How do NO2, and iso-, sevo-, and desflurane affect BP?
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Cause vasodilation (decrease PVR)
(Note: this, causes a reflex tachy) |
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Why may recovery from halothane/enflurane be slower?
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Storage in the liver (can cause toxicity)
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Which inhaled GA is suitable for mask inductions?
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Sevoflurane
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What are some side effects of desflurane?
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Is irritating to airway --> can cause coughing
Can cause hypertension and tachycardia |
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Why are higher inspired concentrations of desflurane required?
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It is less soluble
Thus, it has faster uptake |
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What is a serious side effect of NO2?
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Inhibits methionine synthase
(SO, prolonged use can depress BM or fetal tissue) |
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What is the effect of NO2's high MAC?
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NO2 requires use of other drugs for complete anesthesia
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Mechanism for I.V. GAs
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Activation of GABA-A receptors
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What causes termination of GA effects?
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Redistribution
(NOT elimination) |
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What niche does etomidate fill?
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Rapid induction of anesthesia for pts. w/ IMPAIRED CV STATUS
(Causes less cardiac depression) |
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What are the main side effects of etomidate (3)?
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Irritation on injection
Myoclonic jerking Inhibition of synthesis of cortisol and aldosterone |
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What is the standard drug for induction of general anesthesia?
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Propofol
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Which GA is closes to being a complete anesthetic?
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Propofol
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Mechanism of ketamine
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Blockade of NMDA receptors
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What type of pain relief is ketamine good for?
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Pain relief for superficial procedures
NOTE: blocks visceral pain poorly |
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Why is ketamine good for induction in hemodynamically unstable pts.?
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Maintains or stimulates the CV system
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What drug is ketamine related to?
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PCP
SO, it can cause hallucinations |
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What drugs are used to block ketamine-induced hallucinations?
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BDZs
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Nitrous-narcotic technique
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When NO2 is combined w/ fentanyl (or related drug)
Together, the two drugs can produce complete anesthesia |
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What are pancuronium (and related drugs)?
What are they used for? |
NM blocking agents
Enhance muscle relaxation in procedure where < MAC of an agent is employed NOTE: when these are used, mechanical ventilation is required |
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What is ketorolac?
What is it used for? |
NSAID
Adjunctive analgesic |
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What is neostigmine?
What is it used for? |
Cholinesterase inhibitor
(Remember, has some intrincic muscarinic activity) Reverses the effect of paralyzing drugs |
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What is glycopyrrolate?
What is it used for? |
Muscarinic blocker
Protective medication during anesthesia Prevents excess salivation Prevents neostigmine's effects such as bradycardia |
