The rate of uptake of sevoflurane during clinical anaesthesia (1.3 MAC
) was measured by computer-controlled injection of liquid anaesthetic
into a closed breathing system. The cumulative uptake of sevoflurane w
as 4.8 mi, 7.4 mi. 9.5 mi and 11.5 mi at 30, 60, 90 and 120 min, respe
ctively. The ratio of inspired to end-expired sevoflurane was greater
than similar measurements we have made for desflurane in the past, but
the absolute rate of sevoflurane uptake was less than the rate of upt
ake of desflurane in these cases. The rate of uptake was equivalent to
0.59e(-0.32t) + 0.039e(-0.036t) + 0.105e(-0.0034t) ml.min(-1) liquid
sevoflurane. Plasma urea and creatinine measured on the first postoper
ative day were not significantly different from pre-operative values.