Clinical agreement and physiological relevance of the zero-heat-flux temperature measurement in trauma patients during operating room resuscitation

Hypothermia is common in trauma patients and related to increased mortality; therefore, monitoring of core temperature is important. Conventional measuring methods have limitations in trauma setting. The 3 M™ Bair Hugger™ Temperature Monitoring System provides noninvasive zero-heat-flux temperature but has not been evaluated in trauma patients. This retrospective study included trauma patients who were monitored with esophageal and ZHF temperature monitoring during operating room resuscitation between January to October 2021 at a level I trauma center. Patients with severe facial or head trauma were excluded. Temperature data, automatically recorded every 5 min, were analyzed using Bland–Altman analysis and Lin’s concordance correlation with correction for repeated measurement. A total of 54 patients (mean Injury Severity Score 27.2 ± 14.8) and 1,737 paired measurements were analyzed. Mean bias was − 0.22 °C (95% limits of agreement [LOA], − 1.30 to 0.85 °C; p < 0.001), indicating that esophageal temperature was slightly lower than zero-heat-flux temperature. Lin’s concordance correlation coefficient was 0.759 (95% CI, 0.674–0.825), showing moderate agreement. After excluding hypothermic values (< 34 °C), 1,591 paired measurements remained. Bias was − 0.23 ± 0.45 °C (95% LOA, − 1.11 to 0.65 °C), and concordance improved to 0.846 (95% CI, 0.716–0.864). Zeto-heat-flux temperature measured by the 3 M Bair Hugger system shows moderate agreement with esophageal temperature, with improved precision when extreme hypothermia is excluded. Although not interchangeable, it may serve as a safe, noninvasive option for trend monitoring in emergency trauma surgery. NCT05770830 (ClinicalTrials.gov).