Noninvasive determination of core temperature during anesthesia

A noninvasive, zero heat flux method of determining core (intracardiac blood) temperature was studied in ten anesthetized patients having whole body hyperthermia for the treatment of cancer. True intracardiac blood temperature was determined by a calibrated pulmonary artery thermistor. Accuracy, precision, and responsivity for the noninvasive system were comparable to conventional esophageal thermometry in reflecting intracardiac blood temperatures. This method of contact thermometry is convenient and independent of environmental influence, and it rapidly reflects the small changes in arterial blood temperature which evoke vasomotor responses.