Studies during open-heart surgery on the special characteristics of rectal temperature.

Accuracy of infrared ear thermometry in adult patients

“…Although older studies suggest that rectal temperature may correlate poorly with core temperature [3][4][5], this at least appears to be a better indicator of core temperature than axillary or oral temperatures [2,6].…”

Temperature measurement in intensive care patients: comparison of urinary bladder, oesophageal, rectal, axillary, and inguinal methods versus pulmonary artery core method

“…Historically, the rectal route was preferred to measure a patient's core temperature. However, rectal temperature significantly lags behind other core sites such as the oesophageal site, especially during acute temperature alterations [2,3]. This method also poses the potential risk of rectal perforation and could be uncomfortable for the patient.…”

Validation of Two Temperature Pill Telemetry Systems in Humans During Moderate and Strenuous Exercise

“…In laboratory tests, either rectal or esophageal temperature of the volunteers is monitored to ensire that internal body temperature (core temperature) does not exceed safe clinical limits. Each of these core temperature indices is reproducible and not biased by environmental temperature (2,8,14); however, the slow response time of rectal temperature is well known (7,8,11,15,16). Esophageal temperature measurements are not used in the field, but are routinely used in laboratory tests which are concerned with the study of thermoregulation.…”