TEMPERATURES MEASURED BY A DEEP BODY THERMOMETER (CORETEMP(R)) COMPARED WITH TISSUE TEMPERATURES MEASURED AT VARIOUS DEPTHS USING NEEDLES PLACED INTO THE SOLE OF THE FOOT

Continuous monitoring of body temperature during anaesthesia is a wide ly accepted clinical practice for which a variety of techniques are us ed. In this study, the accuracy of the deep body thermometer (Core-tem p(R)) was compared with temperatures measured by needle thermocouples. With IRE approval and informed consent, seven ASA physical status I a nd II patients undergoing otolaryngeal surgery were stud led. General anaesthesia and neuromuscular blockade were induced with thiamylal and vecuronium. Anaesthesia was maintained with isoflurane at an endtidal concentration of 1.0-2.0% and 66% nitrous oxide in oxygen. After indu ction of general anaesthesia, subcutaneous temperature was measured at the sole of the left foot using a Coretemp(R). Additionally, 8-, 18-, and 38-mm-long needle thermocouples were inserted into the the sole o f the left foot close to Coretemp(R) and skin-surface temperature was also recorded adjacent to the needles. The Coretemp(R) measurement (Tc ) correlated best with 18-mm-deep needle temperature (r(2)=0.87). Ther e was also a good correlation between Tc and 38-mm-deep needle tempera ture (r(2)=0.83). Skin and 8-mm-deep needle temperatures correlated po orly or only moderately with Tc (r(2)=0.67, 0.75, respectively). These results indicate that temperatures measured by Coretemp(R) well refle ct the temperatures at a depth of 18 mm or more from the skin into the foot.