Prospective evaluation of nonporous wrap fails to minimize inadvertent perianesthetic hypothermia in healthy canine patients undergoing ovariohysterectomy.

Objective: To prospectively evaluate a nonporous wrap's ability to prevent inadvertent perianesthetic hypothermia (IPH) in canines undergoing ovariohysterectomy.

Methods: All client-owned canines and felines undergoing ovariohysterectomy performed by preclinical veterinary students at Michigan State University between November 2022 and November 2023 were prospectively enrolled into 1 of 4 treatment groups using block randomization. Patients were excluded if they were unamenable to rectal temperatures, had a body temperature ≥ 103.5 °F (39.7 °C), had incomplete medical records, or were a feline. All patients received intraoperative active warming via a circulating warm water blanket (AW). Experimental treatment groups were supplemented with nonporous wrap placed to either the distal extremities (AW+Limbs), around the head (AW+Head), or to the distal extremities and head (AW+Limbs+Head). Core temperatures were monitored from intubation to extubation. Normality was verified with the Kolmogorov-Smirnov test. Analysis included ANOVA/ANCOVA and regression. Continuous variables were centered for analysis.

Results: 50 canines were enrolled. No statistically significant difference in preventing IPH with the use of supplemental nonporous wrap was identified. The decreases in rectal temperatures were 3.8 °F (AW), 3.7 °F (AW+Limbs), 5.3 °F (AW+Head), and 4.1 °F (AW+Limbs+Head). No intraoperative or postoperative complications associated with wrap placement were reported.

Conclusions: Placing nonporous wrap on canines undergoing ovariohysterectomy resulted in no statistically significant benefit in combating IPH.

Clinical relevance: Supplementing active warming with a nonporous wrap placed to enable evaluation of a blink reflex cannot be recommended at this time.