Standardizing Perioperative Heat to Improve Mouse (Mus musculus) Recovery

Maintaining the core body temperature of anesthetized rodents is essential because of the depression of physiologic homeostasis caused by anesthetics. The maintenance of core body temperature is influenced by the ability of the heating device to provide sufficient heat, the presence of material that might alter heat transfer, and the administration of heat in the period surrounding anesthesia. In this study, optimal heat transfer from 4 unique heating devices, with or without insulating drapes, was determined initially with an inert model. Optimal animal recovery, as evaluated by recovery to baseline activity and normothermic temperature of postoperative animals implanted with an intrabdominal thermometer and monitored with a digitally ventilated caging, was achieved by a device that provided consistent electrically supplied heat at 40 °C throughout the perianesthesia period including 35 minutes before isoflurane anesthetic induction. Animals without preoperative heating required at least 24 hours to return to normal core temperature and normal circadian activity levels.