Objective: When treating patients with cardiac arrest with mild therapeutic hypothermia, a reliable and easy-to-use temperature probe is desirable. This study was conducted to investigate the accuracy and safety of tracheal temperature as a measurement of body temperature.
Design: Observational cohort study.
Setting: Emergency department of a tertiary care university hospital.
Patients: Patients successfully resuscitated from cardiac arrest intended for mild hypothermia therapy.
Interventions: Intubation was performed with a newly developed endotracheal tube that contains a temperature sensor inside the cuff surface. During the cooling, mild hypothermia maintenance, and rewarming phases, the temperature was recorded minute by minute. These data were compared with the temperature assessed by esophageal and blood temperature probes. Thereafter, tracheoscopy was performed to evaluate the condition of the tracheal mucosa.
Measurements and main results: Approximately 2000 measurements per temperature sensor per patient were recorded in 21 patients. The mean bias between the blood temperature and the tracheal temperature was -0.16 degrees C (limits of agreement: -0.36 degrees C to 0.04 degrees C). The mean bias between the esophageal and tracheal temperatures was -0.22 degrees C (limits of agreement: -0.49 degrees C to 0.07 degrees C). Agreement between temperature probes investigated by the Bland-Altman method showed a mean bias of less than -(1/4) degrees C, and time lags assessed graphically by hysteresis plots were negligible. No clinically relevant injury to the tracheal mucosa was detected.
Conclusion: Temperature monitoring at the cuff surface of an endotracheal tube is safe and provides accurate and reliable data in all phases of therapeutically induced mild hypothermia after cardiac arrest.