Skeletal muscle kinetics of propofol in anaesthetized sheep: effect of altered muscle blood flow

Abstract

1. The kinetics of propofol were studied in vivo in a skeletal muscle bed of the hindlimb of the anaesthetized sheep at normal and low rates of blood flow. 2. Propofol kinetics in muscle were determined during and after a 20-min i.v. infusion of propofol (10 mg min-1) via paired arteriofemoral venous blood sampling. One-and-a-half hours later, the study was repeated but with a concurrent left femoral artery infusion of adrenaline (0.004 mg min-1) to lower the muscle blood flow by vasoconstriction. 3. Muscle blood flow in the low flow state was 28% of that in the normal state. The kinetics were poorly described by a single flow-limited compartment model, but were better described by a model with a flow-limited component and a deeper distribution component. There were no significant differences in muscle retention of propofol between normal and low flow states. 4. There was an apparent arteriovenous shunt of approximately 24% of total muscle blood flow for the low flow state, but not for the normal blood flow state.