Always Obtain a Rectal Temperature to Detect Febrile Illness

gender, core temperature, or ambient temperature. Rectal temperatures arewidely believed to be about 0.6°C (1°F) higher than oral temperatures. While it is true that rectal temperatures are usually higher than oral or axillary temperatures, the exact relationship is variable and unpredictable. While some feel that rectal thermometry is a valid method of determining core body temperature, exact measurements of core body temperature require invasive techniques such as esophageal, bladder, or pulmonary artery catheters. Such devices are neither practical nor desirable in the emergency department. Many authors advocate rectal thermometry over other sites as the gold standard among noninvasive temperature methods because it offers high precision and accuracy.,16-18 Obtaining a rectal temperature, however, can be time-consuming and embarrassing to the patient.Furthermore, patients who have had recent rectal surgery, rectal injury, inflammation, or neutropenia are not candidates for rectal thermometry. How accurate and close to core body temperature must we measure in order to ensure that we are not missing essential data? What about the By A l i s on Po r tno y, MD Wehaveall experienced it. A patient with unexplained tachycardia or tachypnea until that lastmomentwhen you check a rectal temperature and discover he was febrile all along. His fever was “missed” by oral, tympanic, or axillary measurement. What form of thermometry can be trusted? How important is it to obtain a rectal temperature on every patient suspected of febrile illness but whose oral, axillary, or tympanic temperature is in the normal range? Aren’t these other methods of obtaining a temperature sufficient?