The effects of general anaesthesia on body temperature of dogs subjected to ovariohysterectomy or orchiectomy performed by veterinary students in a teaching hospital

Hypothermia during anaesthesia is a significant concern in veterinary practice, as it can lead to various complications, making it essential to understand the factors that contribute to temperature regulation in animals undergoing surgical procedures. This retrospective study aimed to evaluate the change in body temperature over the course of anaesthesia in dogs undergoing elective ovariohysterectomy and orchiectomy, and determine the effect of gender, dose of premedication, weight, age and duration of anaesthesia of the change of body temperature over time. One-hundred and ten dogs (n=110) that underwent elective ovariohysterectomy (n=75) and orchiectomy (n=35) surgery performed by veterinary students at the University of Adelaide were enrolled in this study. Dogs' anaesthesia records were evaluated for change in body temperature over the course of anaesthesia, and correlated with gender, two premedication doses of acepromazine (mg/kg), body weight (kg), age (months) and anaesthesia times (minutes). The analyses were performed at TPm (temperature at premedication), T0 (induction), T15, T30, T60, T90, T120 and TRec (recovery) minutes. Statistical analysis was performed using the GenStat software and included repeated measures analysis and ANOVA. Significance was considered when p < 0.05. The data showed a significant time-by-gender interaction with female dogs experienced a greater degree of heat loss than male dogs at T60 (p<0.01), T90 (p<0.01) and T120 (p<0.01). At recovery, female average temperature was higher than in males (p<0.01). There was no significant difference in body temperature when other covariates were used in the analysis. The core body temperature of female dogs decreased significantly over time compared to males, with the most pronounced differenced during the intraoperative period. However, the study's retrospective nature and limited sample size may influence the generalizability of these findings.