Comparison of peripheral and core temperatures in anesthetized horses

Objective-To examine temporal patterns of rectal, nasal, groin, and skin te mperatures measured in adult horses undergoing general anesthesia and to de termine accuracy and precision of temperatures at these sites, compared wi th core temperature. Animals-5 healthy adult horses, Procedure-induction, maintenance of, and recovery from general anesthesia w ere performed in an air-conditioned surgical suite. Room temperature and re lative humidity were approximately 21 C and 40%, respectively, Anesthesia w as maintained for 2.5 hours, and body temperatures were measured and record ed every 5 minutes. Mean values were compared by use of ANOVA for repeated measures. Correlation coefficients for linear regressions of site temperatu re versus core temperature at 30-minute intervals were used to evaluate pre cision. Results-Rectal temperature decreased in a linear manner, similar to core te mperature. Nasal, groin, and skin temperatures followed a biphasic pattern; they sharply increased initially, peaked, then decreased at a rate similar to that of core temperatures. Rectal temperature always accurately reflect ed core temperature, initial significant differences between core temperatu re and nasal, groin, or skin temperature disappeared as peripheral site tem peratures approached peak values. Precision of core temperature estimation was generally poor for rectal, groin, and skin temperatures but was high (r > 0.90) after the first hour of anesthesia. Conclusion-Anesthesia-induced core heat redistribution develops with minima l effect on core temperature. Rectal temperature can accurately reflect cor e temperature.