Oxygen consumption and cooling rates in immersion hypothermia in the dog.

M ANY observations have been made on the effect of reduced body temperature on oxygen consumption. Overall conclusions are made difficult, however, by the wide range of experiment designs. Whether anesthesia was used, if so, depth and type, method of inducing hypothermia, duration of exposure, and species variation are but a few of the many factors tending to preclude generalizations. Too, variation in shivering response within a given set of experiments must be considered. While the rate of cooling of the intact organism has received considerably less critical analysis, it likewise is subject to the same variables mentioned above. In an effort to derive a clear picture of the response of the hypothermic dog a series of experiments was designed wherein the procedure was constant. From these experiments it is apparent that shivering, which is in large measure an individual characteristic (at least under anesthesia), has a profound influence on oxygen consumption and rate of cooling. Only at the lowest extremes of body temperature, below which shivering is never seen, is it possible to predict accurately the metabolic response of a given animal.