Studies of temperature balance after open-heart surgery

An analysis of postoperative records over a two-year period has shown that a mean rise in central body temperature greater than 2 degrees occurs in patients within 12 hours of return from the operating room following open-heart surgery. In some patients the central body temperature may rise to greater than 41 degrees C. despite an adequately warm peripheral temperature, and this is associated with a high mortality rate. An apparatus has been developed which enables the immediate enviroment of the patient to be controlled. A comparison of two groups of patients, in one of which the apparatus was used, demonstrated that it was possible to attenuate significantly the usual postoperative temperature rise seen in the control group. In a third group further cooling was employed: these patients were successfully held at subnormal temperatures. Using multiple temperature probes and heat balance formulas, it was shown that the rise in central body heat was due mainly to elevation of total body heat rather than the result of redistribution of heat from the surface.