Acute changes in oxygen consumption and body temperature after bum injury

This study describes the pattern of oxygen consumption (Vo2), rectal temperature (Tr), and acral skin temperature (T.) in sleeping and resting (awake) burned children nursed in a thermoneutral environment. Measurements of respiratory gas exchange (Vo2 and carbon dioxide production (Vco2)) were made using an open circuit, flow through system of indirect calorimetry. Tr and T. were monitored continuously. Sixteen patients were studied during the first 18 hours after being burned. Three phases of change in Vo2, Tr, and T. are described. The first was a stable period and there was little change from admission values. The second (7-10 hours after burn) was a phase of rapid heat storage. It started with a fall in T.. Peak values ofTr (38.8-41.1, median 40.0°C) and Vo2 (8.5-11.8 mI/mi/kg) occurred either in phase 2 or in the later phase 3. At its peak Vo2 was 12-61% above values in phase 1. In phase 3, T. returned towards admission values but Tr and Vo2 were variable. These changes suggest that both an increase in metabolic heat production as weli as heat conservation at the extremities may be involved in the generation of early fever after a burn. (Arch Dis Child 1994; 71: 31-34) MRC Trauma Group, North Western Injury Research Centre, University of Manchester Charmaine Childs R A Little Regional Paediatric Burns Unit, Booth Hail Hospital, Manchester Charmaine Childs Correspondence to: Dr Charmaine Childs, Burns Unit, Booth Hall Children's Hospital, Charlestown Road, Blackley, Manchester M9 2AA. Accepted 22 February 1994 Fever is a characteristic feature of the acute response to moderate and severe burn injury in infants and young children. Six to eight hours after the accident, deep body temperature rises rapidly and skin temperature in acral regions falls.' These changes reflect the onset of a disturbance in thermoregulation that persists for at least the first 24-48 hours after the event. This pattern of change in body temperature appears to be confined to burned children. While a rise in deep body temperature has been shown in burned adults, the peak is not reached until about 24 hours after the burn.2 The increased amount ofheat stored acutely in these children fails to stimulate efferent pathways of heat loss. Sweating is inhibited and heat loss is reduced in acral regions. Despite differences in the routes for heat loss by radiation, convection and evaporation, total heat loss is not very different from that of healthy apyrexial children exposed to similar environmental conditions.3 The rise in deep body temperature must therefore involve an increase in oxygen consumption and metabolic heat production.3 In this study, oxygen consumption has been measured by indirect calorimetry in a group of burned children nursed in a thermoneutral environment during the first 18 hours after the event. The results were compared with those in healthy children studied under similar environmental conditions.4