Effect of inspired-air warming and humidification in the prevention of hypothermia during general anesthesia in cats.

An inspired-air heating and humidifying device was constructed and evaluated with regard to its ability to maintain mean body heat in anesthetized cats. Control cats exhibited a net heat loss of -5.960 and -2.970 Kcal for each of 2 successive hours. The respiratory heat loss was only 0.675 Kcal per hour. Subjects inhaling warmed and humidified oxygen exhibited a net heat loss of -2.860, -1.900, and -0.742 for each of 3 successive hours, whereas respiratory heat gain was 0.643, 0.742, and 0.776 Kcal for the same periods. The inspired-air heating and humidifying technique was associated with a significantly slower decrease in body temperature (P less than 0.05) after 45 minutes. The inspired-air heating technique is beneficial in minimizing body heat loss during general anesthesia in cats, but is not effective enough to supplant other methods.