Changes in skin thermal clearance during anaesthesia.

Thermal and vascular side effects occurring during general anaesthesia are related to skin blood flow. A new, noninvasive probe which measures skin thermal clearance, a variable closely related to skin blood flow, was used in nine patients under phenoperidine, droperidol, propanidid anaesthesia. Statistically significant increases in skin thermal clearance clearly preceded the drop in mean arterial blood pressure and the rise in skin temperature. It is concluded that general anaesthesia induced an early increase in skin blood flow and that thermal clearance is a better technique than skin thermometry to monitor skin blood flow.