Comparison of Temporal Artery and Rectal Temperature Measurement During Cooling and Rewarming in Neonates Treated for Hypoxic Ischemic Encephalopathy.

BACKGROUND

Finding an accurate and simple method of thermometry in the neonatal intensive care unit is important. The temporal artery thermometer (TAT) has been recommended for all ages by the manufacturer; however, there is insufficient evidence for the use of TAT in infants, especially to detect hypothermia.

PURPOSE: To assess the accuracy of the TAT in hypothermic neonates in comparison to a rectal thermometer.

METHODS

This study was a naturalistic, quantitative, and observational study. Temporal artery temperatures (using Exergen TemporalScanner 5000) were compared to rectal temperatures in critically ill infants in the neonatal intensive care unit undergoing therapeutic hypothermia for hypoxic ischemic encephalopathy. Temperatures were taken during a 72-hour cooling period at 33.5 °C and a 6-hour rewarming period to normothermia of 36.5 °C. Nineteen patients and 1280 temperature measurements were included in this study.

RESULTS

During the cooling period, TAT and rectal temperatures had a weak correlation (r = 0.34, P < .001). The correlation during the rewarming period was much stronger (r = 0.70, P < .001), indicating less variability in measures, but not agreement. On average, regardless of period, the TAT temperatures read 0.43 °C (95% confidence interval, 0.37-0.49, P < .001) warmer than the rectal temperatures. The cooling or warming period had no effect on this difference between temperatures.

IMPLICATIONS FOR PRACTICE AND RESEARCH: This study found that temperatures obtained with a TAT are generally warmer than the accepted standard core rectal temperature in hypothermic neonates, and we do not recommend its use in critically ill neonates who require accurate temperature readings.