COMPARISON OF EAR-BASED, BLADDER, ORAL, AND AXILLARY METHODS FOR CORETEMPERATURE-MEASUREMENT

Objective. To determine the accuracy and repeatability of ear-based, b ladder, oral, and axillary temperature methods. Design: Prospective, d escriptive comparison of the accuracy of four temperature methods in r elation to pulmonary artery temperature and the repeatability of each method. Setting. Critical care units of a university teaching hospital . Patients: Convenience sample of 38 adult patients with indwelling pu lmonary artery thermistor catheters. Interventions: None. Measurements and Main Results: Ear-based estimates of core temperature with an inf rared thermometer and pulmonary artery, bladder, oral, and axillary te mperatures with thermistor-based instruments were made every 20 mins f or 4 hrs. Mean offsets (+/- SD) from pulmonary artery temperature for each method were as follows: ear-based 0.07 +/- 0.41-degrees-C; bladde r 0.03 +/- 0.23-degrees-C; oral 0.05 +/- 0.26-degrees-C; and axillary -0.68 +/- 0.57-degrees-C. The accuracy of each method varied with the level of pulmonary artery temperature. Repeated measurements with all four methods had mean SD values within +/- 0.2-degrees-C. Conclusions: Infrared ear thermometry provided a relatively close estimate of pulm onary artery core temperature, although with more variability than bla dder or oral methods, while axillary readings were substantially lower than the pulmonary artery temperature and highly variable.