· Summary
· Determinants
· Kinetic model
· Washout graph
· Decrement graph
Multiphasic |
· Distribution: (excretion) x (distribution V1 -> V2-5) · Terminal elimination: (excretion) x (metabolism) / (redistribution V2-5 -> V1) |
Exponential |
· Rate of drug elimination ∝ partial pressure |
Rapid |
· Low tissue solubility -> minimal uptake -> rapid excretion · Almost flat 90% decrement curve hence offset is almost duration-independent |
Tissue -> blood |
↑Tissue blood flow (i.e. cardiac output) ↓Compartment volume (i.e. not obese) ↓Duration of anaesthesia |
Blood -> alveolus |
↑Cardiac output |
Alveolus -> circuit |
↑Alveolar ventilation : FRC (e.g. child or pregnant) |
Circuit -> atmosphere |
↑Fresh gas flow rate : circuit volume |
N.B. high cardiac output mainly slows washout due to greater drug uptake
Muscle:blood partition coefficient 2.0
(cf. sevo 3.1)
Fat:blood partition coefficient 29 (cf. sevo 48)
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