Changes in cerebral oxygen consumption are independent of changes in body oxygen consumption after severe head injury in childhood

Abstract

This study examines the relation between cerebral 02 consumption (CMRo,) and the 02 consumption of the rest of the body (BVo 2) after severe head injury. Seventy nine serial measurements of whole body 02consumption, CMRo, plasma adrenaline, T3, and glucagon concentrations were made in 15 children with severe head injuries receiving neurointensive care. Body 02 consumption was measured with indirect calorimetry and CMRo2 with the Kety-Schmidt technique. There was no evidence of a significant relation between CMRo2 and BVo,. Within each child there were statistically significant positive relations between BVo, and adrenaline, T3, and glucagon. By contrast, there was only a weak significant positive relation between CMRo0 and T3. In conclusion, CMRo2 and BVo, seem to be determined independently after severe head injury. Thus therapeutic measures aiming to reduce CMRo, need to be specific to the brain and it should not be assumed that measures which decrease whole body energy expenditure will necessarily have the same effect on CMRo02.