Continuous monitoring of skin temperature using a liquid-crystal thermometer during anesthesia

Forehead skin temperature measured by a stip of liquid-crystal material was compared to esophageal, rectal, and axillary temperatures measured by thermistor probes in patients having general anesthesia for coronary artery bypass grafting. Before extracorporeal circulation, forehead skin temperature was lower than axillary, rectal, and esophageal temperatures by approximately 2.2 C (4.0 F). During rapid warming, forehead skin temperature rose concurrently with the other temperatures measured but remained significantly different. The liquid-crystal strip may be useful as a safe, convenient method for routine monitoring of temperature trends during general anesthesia in patients whose exact core temperature need not be continuously monitored. We believe that infants, patients undergoing extracorporeal circulation, major abdominal, vascular, or neurosurgical procedures, or patients with a history of temperature regulatory problem are probably best monitored by a method which more exactly reflects core temperature.