Anesthetics - Inhalational Flashcards
myer-orton hypothesis
activity linked to lipid solubitlity
MAC
concentration inspired gas required to render 50% of patients unconscious (↓MAC = ↑potency).
inhalational anesthetics
nitrous oxide, isoflurane, desflurane, sevoflurane
MOA of inhalational anesthetics
Inhaled agents have reinforcement of GABA and glycine inhibitory signaling, reinforcement of tow pore potassium channel activity and inhibition of glutamatergic signaling
general effects of liquid inhalational anesthetics
∙ ↑respiration rate & ↓tidal volume ∙ Reflex response to PaCO2 blocked ∙ ↓SNS ∙ ↓adrenal catecholamine release ∙ ↓Ca flux
what general effect does N2O not share with the other inhalational anesthetics
N2O has no significant CV effects
AE of nitrous oxide
teratogen in animals, neurologic deficits in infants due to myelin sheath degeneration, inhibitor of B12 synthetase;
3 specific issues with nitrous oxide
has second gas effect, can cause diffusion hypoxia and there is potential problem with air spaces due to density (34x N)
ADM of nitrous oxide
A: ↑MAC
D: ↓ B:G partition coefficient, relatively insoluble so reaches brain quickly
M: ↓↓metabolism
AE of isoflurane
irritating odor, +/- pain relief, muscle relaxation, loss of reflexes
AE desflurane
irritating odor, loss of reflexes
DM of desflurane
D: ↓B:G partition coefficient & reaches brain quicker than halothane
M: ↓↓metabolism
AE of sevflurane
loss of reflexes
DM of sevoflurane
D: ↓B:G partition coefficient & reaches brain quicker than halothane
M: ↓↓metabolism
clinical utility of nitrous oxide
Due to ↑ absorption compared to the volatile anesthetics, N2O is given in conjunction to ↓ anesthetic dosage required
