Central thermometers preferred to peripheral when temperature could influence diagnosis, treatment
Peripheral thermometers had poor clinical accuracy and poor sensitivity for detecting low-grade fever compared with central thermometers.
Peripheral thermometers used orally or under the arm do not have clinically acceptable accuracy and should not be used when accurate measurement of body temperature might influence clinical decisions, a meta-analysis found.
Researchers reviewed 75 published prospective studies comparing the accuracy of tympanic membrane, temporal artery, axillary, or oral thermometers (peripheral thermometers) with pulmonary artery catheter, urinary bladder, esophageal, or rectal thermometers (central thermometers). The results of the systematic evidence review and meta-analysis were published Nov. 16 by Annals of Internal Medicine.
Peripheral thermometers had poor clinical accuracy and poor sensitivity for detecting low-grade fever compared with central thermometers, the researchers noted. Compared with central thermometers, peripheral thermometers had pooled 95% limits of agreement (random-effects meta-analysis) outside the predefined clinically acceptable range (± 0.5 °C), especially among patients with fever (−1.44 °C to 1.46 °C for adults; −1.49 °C to 0.43 °C for children) and hypothermia (−2.07 °C to 1.90 °C for adults; no data for children). For detection of fever, the peripheral thermometers' sensitivity was low (64%; 95% CI, 55% to 72%; I2 = 95.7%; P<0.001) but specificity was high (96%; 95% CI, 93% to 97%; I2 = 96.3%; P<0.001).
Researchers suggested that clinicians consider using central thermometers when accurate measurement of a patient's temperature will influence diagnosis and management. Rectal thermometers could be used for most of these patients, and bladder thermometers could be used for those requiring a bladder catheter. When a central thermometer is best avoided, tympanic membrane thermometers that are calibrated before use seem to be the best alternative, they said.
“At extremes of body temperature, peripheral temperature measurements may be as much as 1 to 2 degrees higher or lower than actual body temperature,” the authors wrote. “Peripheral thermometers therefore represent a poor screening tool for detecting temperature abnormalities. In contrast, nonvascular central thermometers show excellent agreement with the gold standard, the pulmonary artery catheter, which confirms their clinical utility. Taken together with previous meta-analyses in children, our study provides clinically meaningful insight into the most appropriate means of monitoring a vital sign.”