Bedside infrared thermometry compared with continuous zero-heat-flux thermometry– an experimental and clinical study

This study compared standard infrared thermometers used in emergency rooms (ER) and wards to a Zero-Heat-Flux (ZHF) thermometry device and evaluated its feasibility for continuous bedside temperature monitoring. In 60 volunteers, five alternative ZHF sensor placements were assessed against the conventional forehead position (“ZHF-forehead”). Based on these results, continuous ZHF-forehead monitoring was evaluated in 24 hip-fracture patients in an ER (21 patients) and ward (11 patients). Concurrent ZHF and infrared forehead (“IR-forehead”) and ear canal measurements (“IR-ear”) were compared using Bland–Altman analysis (bias, limits of agreement). Among alternative placements, the neck (“ZHF-neck”) showed the closest agreement with ZHF-forehead (0.2, -0.5–0.8 °C). Compared to ZHF-forehead, ZHF-neck did not show improved agreement with either IR-forehead (ZHF-forehead: 0.0, -0.5–0.5 °C vs. ZHF-neck: -0.3, -1.1–0.5 °C) or IR-ear measurements (ZHF-forehead: 0.2, -0.3–0.8 °C vs. ZHF-neck: -0.1, -0.8–0.7 °C). All ER patients showed stable ZHF-forehead temperature profiles, whereas 4 of 11 ward patients had unreliable measurements. Bedside ZHF-forehead measurements in the ER and ward showed moderate agreement with infrared measurements (0.2; -0.4–0.7 °C). In conclusion, ZHF-forehead thermometry showed moderate agreement with point-of-care infrared methods in volunteers and patients, and provided stable continuous bedside temperature measurements in the ER and ward.