The sticker-type skin-surface temperature indicator in anesthesia

Abstract

The sticker-type skin-surface temperature indicator ProChecker (Kyowa Medex Tokyo, Japan) is a skinsurface temperature monitor that enables continuous and long-duration measurement of body temperature by merely attaching it to the body surface [1]. ProChecker indicates temperature in increments of 2 ~ and body temperature can be read by changes in color at a precision of 0.5 ~ (Fig. 1). We studied the usefulness of ProChecker as a surface temperature monitor during anesthesia by comparing the skin surface temperature measured by Prochecker with the rectal temperature measured by thermometer.The present study included 18 patients (age 11-75 years, body weight 42-70 kg) who underwent laparotomy under general anesthesia. Informed consent was obtained from eac]h patient. To measure the skin surface temperature, ProChecker and the PTP-50 sensor of the thermocouple thermometer PTW-100A (Unique Medical, Tokyo, Japan) were placed side by side on the center of the forehead and on the forearm. The rectal temperature was measured using an electronic thermometer ETC-21A (Top, Tokyo, Japan). During surgery, all temperatures were monitored continuously and recorded at any points where a change in temperature occurred. The differences between the temperatures measured with ProChecker and with the thermocouple thermometer were investigated. Correlations between temperatures were obtained by the least squares method. A value of less than 0.05 was considered significant. Address correspondence to: T. NishiyamaReceived for publication on January 6, 1994; accepted on August 9, 1994Measurements were taken 115 times on the forehead and 124 times on the forearm with ProChecker, 41 times on the forehead and 54 times on the forearm with the thermocouple thermometer, and 126 times with the rectal thermometer.The temperatures measured with ProChecker were lower than those measured with the thermocouple thermometer (Fig. 2), but the differences were almost within the standard deviation. A highly positive correlation was found between the forearm surface temperature measured with the thermocouple thermometer (Y) and that with ProChecker (X), Y = 0.787X + 6.935, r = 0.896, P < 0.01. In the forehead surface temperature as well, a highly positive correlation was noted between the thermocouple thermometer (Y) and ProChecker (X), Y = 1.244X -7.126, r = 0.833, P < 0.01. No correlation was found between the surface temperatures and the rectal temperature.Body temperature is divided into two categories: core temperature and peripheral temperature. Core temperature includes blood, rectal, esophageal, pharyngeal [2], bladder [3], and tympanic membrane temperature [4]. To measure the peripheral temperature, axillary, skin surface, and deep peripheral temperature [5] are employed. The usefulness of the procedure may change with the measurement environment such as the sites of operation [6,7]. In this study, we used rectal temperature as a monitor for core temperature because this method is the most commonly used during laparotomy. Of the peripheral temp...