Comparison of esophageal, tympanic, and forehead skin temperatures in adult patients.

STUDY OBJECTIVE

To compare esophageal, tympanic membrane, and forehead skin temperatures in patients undergoing elective surgeries.

DESIGN

Prospective clinical study.

SETTING

Operating room and postanesthesia care unit of a tertiary care teaching hospital.

PATIENTS

40 adult ASA status I, II and III patients requiring anesthesia and surgery.

INTERVENTION

Application of crystalline thermometry strips to the forehead of patients.

MEASUREMENTS AND MAIN RESULTS

Concurrent forehead skin, tympanic membrane, and lower esophageal temperatures were measured and compared. The overall bias between esophageal and skin temperatures was 0.3 degrees C, between tympanic membrane and skin was 0.5 degrees C, and between esophageal and tympanic membrane was -0.1 degrees C The limits of agreement (precision) between esophageal and skin temperatures were: -1.64 degrees C to +2.32 degrees C, between esophageal and tympanic membrane were: -1.02 degrees C to +0.74, and between tympanic membrane and skin were: -1.48 degrees C to +2.52 degrees C. There was no significant relation between the change in skin temperature and change in esophageal temperature, whereas there was a weak linear relation between change in skin temperature and change in tympanic membrane temperature (y = -0.03 + 0.09, r = 0.12).

CONCLUSION

There was a lack of precision between the clinically accepted measurements (lower esophageal and tympanic membranes and the skin temperature measurement. The data suggest that forehead skin temperature is not interchangeable with standard core temperature measurements, and that sole reliance on the forehead skin measurement in the perioperative setting could adversely affect patient care.