Evaluation of skin temperature over carotid artery for temperature monitoring in comparison to nasopharyngeal temperature in adults under general anesthesia

BACKGROUND: Thermoregulation is markedly affected in patients undergoing surgical procedures under anesthesia. Monitoring of temperature is very important during such conditions. Skin temperature is one of the easy and noninvasive ways of temperature monitoring. Common skin temperature monitoring sites are unreliable and did not correlate to the core temperature measurement. AIM: To compare and study the correlation of skin temperature over carotid artery in the neck to that of simultaneously measured nasopharyngeal temperature in adult patients undergoing surgical procedures under general anesthesia. SETTINGS AND DESIGN: Prospective double-blinded study in a Tertiary Care Center. MATERIALS AND METHODS: Ninety-seven consecutive American Society of Anesthesiologists I–II patients of age 18–40 years posted for elective surgical procedures under general anesthesia were included. Two temperature sites are monitored: The skin temperature over the carotid artery in the neck with a skin temperature probe T (skin-carotid) and the nasopharyngeal temperature T (naso) with another nasopharyngeal probe. The temperature readings are taken at 0, 15, 30, 45, and 60 min after induction of general anesthesia. STATISTICAL ANALYSIS: Paired t-test, Pearson correlation and Bland–Altman analysis for the rate of agreement. RESULTS: The skin over the carotid artery in the neck showed statistically significant lower values than simultaneously measured nasopharyngeal temperature. This comparison is done with paired t-test at P< 0.05 significance. Bland–Altman plots showed good agreement between the two sites of temperature measurement. CONCLUSION: This study has shown that the skin temperature over the carotid artery in the neck was strongly correlated to the nasopharyngeal temperature in adult patients undergoing surgical procedures under general anesthesia.