Relation between brain oxygen metabolism and temperature gradient between brain and bladder

Abstract

Brain temperature is slightly higher than systemic core temperature normally. Fluctuations of a temperature gradient between brain and core body have recently been reported after a severe brain insult. The pathophysiological significance of the gradient fluctuations is unclear. This study aims to identify the gradient fluctuations between brain and core temperatures after a brain insult. Temperature gradient (brain temperature minus bladder temperature: °C) was measured in 11 patients (125 points) with severe brain injury (4 patients with subarachnoid hemorrhage, 4 with cerebral hemorrhage, and 3 with traumatic brain injury). Cerebral perfusion pressure (CPP; mmHg) and jugular %-enous blood saturation (SjO2; %) was also measured. The average gradient was 0.29 ± 0.285 °C when CPP was above 50 mmHg. SjO 2 was inversely related to the temperature gradient in a significant manner (r = 0.472; P < 0.0001). Temperature gradients tended to increase and then decrease when CPP < 50 mmHg. This study demonstrates that increased temperature gradient has a significant inverse correlation with SjO2 at CPP > 50 mmHg. The current results suggest that the fluctuations in temperature gradient in critical conditions reflect brain ischemia. © Springer-Verlag 2003.