[Validity of non-invasive deep body thermometry to evaluate thermoregulation]

We evaluated, as an index of thermoregulation and hemodynamics, the validity of deep body thermometry that measures deep tissue temperature transcutaneously by creating an area under an insulated thermistor probe of zero thermal flow between skin and subcutaneous tissue in 27 patients undergoing cardiac surgery. Deep body temperatures (DBT) were measured at the forehead (FH) and palm (P), and the DBT gradients (DBTFH-P) were compared with simultaneously measured mean arterial pressure (MAP), cardiac index (CI), systemic vascular resistance (SVR), the gradients (TESODBTP, TRECDBTP) of the esophageal and rectal temperatures and palm DBT during a three hour period after discontinuing cardiopulmonary bypass. Among the body temperature and hemodynamics measurements, the closest linear relationship was found between DBTFH-P and TESODBTP [0.35 + 0.95 x TESODBTP (degrees C), r = 0.98, SEE = 0.45, P < 0.0001]. There were no correlations between DBTFH-P and MAP, CI and SVR. We conclude that the measurement of DBTFH-P is useful as a reliable non-invasive method of monitoring core and shell temperature to evaluate thermoregulation.