Inaccuracy of liquid crystal thermometry to identify core temperature trends in postoperative adults.

In 71 adult postsurgical patients, simultaneous measurement of core (tympanic membrane) and shell (liquid crystal adhesive temperature strip) cutaneous temperature was assessed on admission and every 15 minutes throughout the recovery room stay. Tympanic membrane sensors were inserted into the ear and adhesive temperature strips were applied to the forehead. Although temperature strip temperatures on admission to the recovery room were correlated significantly with tympanic membrane temperatures on admission to the recovery room (r = 0.61, p less than 0.001), subsequent readings 15, 30, 45, and 60 minutes after admission demonstrated decreasing correlation coefficients. Moreover, changes in temperature strip temperatures over the first 15, 30, and 45 minutes of monitoring in the recovery room did not correlate significantly with changes in tympanic membrane temperatures over the same time period. These data suggest that shell temperature (temperature strip) is not a reliable or valid trend indicator of core temperature (tympanic membrane) in postanesthetic adults.