Metabolism after injury: 2. Effect of a dryish and warm environment on skin temperatures and electrolyte responses

Abstract

Abstract Patients with moderate to severe fractures of the major long bones of the lower limb had generally warmer extremities if nursed in cubicles with a dryish (35–45 per cent relative humidity) and warm (29–30° C.) environment than if maintained at a normal temperature of 20–24° C. The additional heat was applied soon after the period of shock was over and was then provided for a further 10–12 days thereafter. The effect of a higher temperature in reducing the protein catabolic response to injury–which seems mainly to involve an increase in the catabolism of some muscle proteins accompanied by increased urinary excretions of potassium, creatine, and zinc–has already been described (Cuthbertson, Fell, Smith, and Tilstone, 1972). The effects of a warmer atmosphere on oral and skin temperatures over various surfaces are described in the present paper and these effects are compared with those found when extra bed coverings are applied under normal ward environmental conditions (20–22° C.). By the application of such heat the skin temperature of the extremities can be raised several degrees; that of the large toes by as much as 12° C. By the use of extra bed coverings conductive losses can undoubtedly be diminished, particularly at normal temperatures. Oral, axillary, and frontal and mastoid process temperatures are not apparently influenced by a higher environmental temperature but appear to be mainly related to the degree of traumatic fever. The advantage of the higher environmental temperature over extra bed coverings is presumed to be mainly in reducing total resting heat production from resting to basal values by providing thermoneutral conditions. Apart from a significant reduction in the rise in serum potassium around the fifth day after injury and a reduction in the normal increased urinary excretion of potassium previously noted, there were no significant changes in the concentration of other serum electrolytes as a result of the higher environmental temperature, nor were the other characteristic electrolyte patterns of urinary excretion altered by the change in the ambient temperature. There were also no distinctive differences in the pattern of urinary amino-acids at the two temperatures.