Appropriate depth for the esophageal stethoscope placement for temperature monitoring - a pilot study

Accurate body temperature monitoring is essential for maintaining a core temperature during general anesthesia. This study aimed to determine the appropriate insertion depth of the esophageal stethoscope (IDE) to measure core body temperature accurately. Fourteen patients undergoing elective surgery in the supine position were included in the study. The esophageal stethoscope was inserted to a depth of 45 cm from the incisors. Then, it was withdrawn se-quentially, 2 cm at a time, at 5-minute intervals. Temperatures of the esophagus according to the IDE were compared with the core temperature of the tympanic membrane (TM) using Bland and Altman analysis. A mean difference of ±1.96 standard deviations in temperatures between TM and esophagus showed a clinically acceptable range of -0.5oC and 0.5oC at the IDE between 43 and 31 cm. At both locations, the Bland-Altman test showed good limits of agreement, but temperatures at IDE 41 cm showed better agreement (the bias of 0.28oC with 95% CI 0.13 to 0.43). Inserting an esophageal stethoscope between 43 and 41 cm will guarantee accurate core temperature monitoring.