Novel Zero-Heat-Flux Deep Body Temperature Measurement in Lower Extremity Vascular and Cardiac Surgery

Objective: The aim of this study was to compare deep body temperature obtained using a novel noninvasive continuous zero-heat-flux temperature measurement system with core temperatures obtained using conventional methods. Design: A prospective, observational study. Setting: Operating room of a university hospital. Participants: The study comprised 15 patients undergoing vascular surgery of the lower extremities and 15 patients undergoing cardiac surgery with cardiopulmonary bypass. Interventions: Zero-heat-flux thermometry on the forehead and standard core temperature measurements. Measurements and Main Results: Body temperature was measured using a new thermometry system (SpotOn; 3M, St. Paul, MN) on the forehead and with conventional methods in the esophagus during vascular surgery (n = 15), and in the nasopharynx and pulmonary artery during cardiac surgery (n = 15). The agreement between SpotOn and the conventional methods was assessed using the Bland-Altman random-effects approach for repeated measures. The mean difference between SpotOn and the was +0.08 degrees C (95% limit of agreement-0.25 to +0.40 degrees C). During cardiac surgery, during off CPB, the mean difference between SpotOn and the pulmonary arterial temperature was-0.05 degrees C (95% limits of agreement-0.56 to +0.47 degrees C). Throughout cardiac surgery (on and off CPB), the mean difference between SpotOn and the nasopharyngeal temperature was-0.12 degrees C (95% limits of agreement-0.94 to +0.71 degrees C). Poor agreement between the SpotOn and nasopharyngeal temperatures was detected in hypothermia below approximately 32 degrees C. Conclusions: According to this preliminary study, the deep body temperature measured using the zero-heat-flux system was in good agreement with standard core temperatures during lower extremity vascular and cardiac surgery. However, agreement was questionable during hypothermia below 32 degrees C. (C) 2016 Elsevier Inc. All rights reserved.