The effect of occlusive dressings on the energy metabolism of severely burned children.

Metabolic studies were performed on 23 burned children. They were studied sequentially until their burn wounds were healed. A metabolic study lasted 20 minutes, during which continuous measurements were made of O2 consumption and CO2 production rates, rectal temperature, average surface temperatures (dressings, skin and wound), body heat content, and rate of body weight loss using a bed scale. These measurements allowed solution of the heat balance equation for each study period. After 24 hours in a constant temperature room kept at 28 C and 40% relative humidity, metabolic studies were initiated when blood was drawn for catecholamine assay, followed by a metabolic analysis, after which dressings were removed and fresh silvadene applied to the wounds. No dressings were applied. Metabolic analyses were repeated after two and four hours of exposure, after which blood for catecholamine analysis was drawn and the study terminated. Without dressings in a thermally neutral environment, burn patients demonstrated an increased rate of heat loss of 27 watts/square meter body surface area (W/M2), compared with the predicted normal. The major portion of this increment is by evaporation, which increased 300%. The rate of heat production equals heat loss, and is increased 50% above the predicted normal. Occlusive dressings result in a 15 W/M2 decrease in the rate of heat loss, about evenly divided between evaporative and dry routes, with a corresponding 15 W/M2 decrease in the rate of heat production. Plasma catecholamine levels of bandaged burn patients are not significantly different from values for healed burn patients, and do not correlate with the rate of heat production. The increased heat production of burn patients is a response to an increased rate of heat loss, not vice versa. The use of occlusive dressings substantially reduces the energy requirements to manageable levels, even in patients with very large burns.