PHARMACODYNAMICS

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THEORIES OF ANESTHETIC ACTION
-unitary hypothesis
-critical volume hypothesis
-fluid theory of anesthesia
-lateral phase separation theory

MINIMUM ALVEOLAR CONCENTRATION (MAC)
-minimum alveolar concentration of an inhaled anesthetic which prevents movement in 50% of patients in response surgical incision
-mirrors brain partial pressures
-allows for comparison of potency amongst differing anesthetic agents
-provides a standard for expiremental observations

MAC (awake): 0.3 MAC
MAC (amnesia): 0.5 MAC
MAC:(ED 50): 1.0 MAC
MAC (ED 95): 1.3 MAC
MAC (BAR): 1.5 MAC

MAC (BAR)= blockade of adrenergic response