Methods of cooling subjects with hyperpyrexia.

Abstract

Six volunteers raised their rectal temperatures to 104℉ by 40–50 minutes' work at 93℉ wet-bulb temperature. The rates of fall in rectal temperatures were studied during cooling by six different methods. The most rapid method of cooling occurred when subjects sat at rest in an air condition of 90℉ dry bulb and 87℉ wet bulb and evaporative cooling was accelerated by wetting the body surface continuously for 1 hour; no significant difference in cooling was observed between airflows of 120 ft/min. and a jet of compressed air held 1–3 ft from subjects. Merely seating individuals in air conditions of 70℉ with 20% relative humidity in still air was almost as effective. Immersion in cold water and sitting in air conditions of 90℉ (D.B.) and 87℉ (W.B.) without aiding evaporative cooling are significantly less effective than the foregoing methods. Resting subjects at 97℉ (D.B.), 93℉ (W.B.) and 120 ft/min. air velocity results in very slow cooling. ‘Afterdrop’ in rectal temperature after ice-cold water cooling may be associated with severe circulatory shock. Oral temperatures are a less reliable index of core temperature than rectal. Submitted on February 16, 1959