Performance of transesophageal echocardiography probe at temperature monitoring during simulated hypothermia and rewarming.

Objective: To determine whether a transesophageal echocardiography (TEE) probe can accurately measure temperature and be used to monitor temperature changes over time without overheating in an experimental model of hypothermia and rewarming.

Methods: A 6L water bath was heated with a sous vide immersion circulator to 24C, 28C, 32C and 36C to simulate severe hypothermia, moderate hypothermia, mild hypothermia, and normothermia. A TEE probe, esophageal temperature probe, and bladder temperature probe were used to measure temperature. Temperatures were recorded every 60 seconds for 15 minutes prior to raising temperature to the next predetermined temperature.

Results: The TEE probe reported temperatures with a mean difference of 0.60°C (95% CI, 0.51°C - 0.69°C) compared to the reported temperature of the sous vide immersion circulator. The esophageal probe and bladder probe reported temperatures with a mean difference of -0.19°C (95% CI, -0.23°C - -0.14°C) and - 0.20°C (95% CI, -0.26°C - -0.14°C) respectively.

Conclusion: During this simulation, the TEE tip temperature did not increase apart from expected changes from water temperature changes. The probe temperature was less accurate than the esophageal and bladder temperature probes but demonstrated precision in monitoring temperature changes and stable hypothermia. Based on this study, TEE probes should not be relied upon for an accurate initial temperature but can likely be used to monitor changes in temperature over time.