Inhalational Anesthetics Flashcards
Analgesia
pain relief but no altered mental state
Anxiolysis
Decreased apprehension with no change in awareness
Conscious sedation
Protective reflexes maintained, Can still breathe independently. Responds to stimulation
Deep Sedation
Profound effects with the loss of one or more functions mintained in conscious sedation
General Anesthesia
Sensory/Mental/Reflex/Motor Blockade. Loss of all protective reflexes
General Anesthetics are
Drugs that produce reversible depression of neuronal function with loss of ability to perceive pain/sensation. Must maintain the pts airway. Frequently requires mechanical ventillation
MAC
Minimum alveolar concentration: minimum concentration required to anesthetize 50% of pts
How does MAC relate to oil:gas partition coefficient
Oil:gas partition coefficient is a measurement of lipophillicity. As the oil gas partition coef goes up, lipophillicity also goes up. The more lipophilic something is, the lower its MAC. Lower MAC means lower dosing
Meyer Overton hypothesis
ANesthetic action is directly linked to drug lipophilicity. Turns out this is way too simple because in some drugs, high lipophillicity means that they are inactive
Know that inhaled drugs potentiate or inhibit lots of different receptors.
They Increase the action of GABA, Glycine, pore K channels
They decrease the action of NMDA
Ultimately leads to less cortical interaction and the frontal cortex decreasing signaling to posterior brain areas
Memory goes first, then awareness, then movement in response to pain, finally autonomics, Pt may not be able to respond to pain but may still fell it
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Drugs with a low blood: gas partition will have a much faster onset of action and they also decrease in action more quickly.
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Anesthesia effects on RR
Anesthesia leads to High resp rate but with a low tidal volume….therefor high CO2. Regular shallow breathing.
CV effects of all but N2O
Lower BP and CO. Directly lowers SNS
