Esophageal, Tympanic, Rectal, and Skin Temperatures in Children Undergoing Surgery With General Anesthesia

Abstract

The purpose of this study was to determine the degrees of agreement between various sites of temperature measurement and examine the trend of body temperature in children during surgery under general anaesthesia. Thirty-six consecutive children who underwent surgery with general anaesthesia, had temperatures measured at the oesophagus, skin, ear canal and rectum at baseline, every 15 minutes for the first hour and every 30 minutes thereafter. Spearman correlation and Bland-Altman analyses were used to compare data and trends of mean differences assessed by line graphs. The median age of the sample was 48 months. There were 575 temperature measurements taken. The inter-method correlation coefficients was highest for the oesophageal vs rectal (r = 0.96) temperature and lowest for rectal vs skin (r = -0.11) temperature. The lowest mean difference (95% CI) in temperature at commencement of surgery was between the oesophageal and rectal sites, -0.03°C (-0.08, -0.01) while the highest mean difference (95% CI) temperature was between oesophageal and skin sites, 3.24°C (2.65, 3.85). The trend in differential temperatures between sites remained throughout the duration of surgery. Bland-Altman plots showed that the least difference (bias) at baseline (0.3°C) was between the oesophageal and tympanic temperatures while at 1 hour (0.13°C ) was between the oesophageal and rectal temperatures. The oesophageal site was the closest to rectal for monitoring core temperature while the skin was the least reliable site in the study population. In the situation where oesophageal probe is not routine or functioning, rectal or tympanic temperatures may be used.