Brain tissue pO2 and outcome after severe head injury

Abstract

Although the use of on-line monitoring of brain ti-p02 is increasing, so far the critical level of 70 mmHg is derived from animal experiments and clinical analyses: no hard proof on outcome basis has been given . until now. The authors present an outcome analysis of35 patients with severe head injury. Inclusion criteria were: start of ti-p02 monitoring ≤40 h post-injury, the probe lying in CT scan normal tissue and the COS at 6 months being available. The good outcome group (COS 4+5/ n = 77) showed a 77.7± 9.1 h delay from the injury to the monitoring compared to the bad outcome group (COS 7-3/ n = 78) with (74.2 ± 9. 7 h) (p < 0.05). Age and initial Glasgow Coma Score were not different. In the bad outcome group there were more patients with a diffuse injury type 3 and 4. The distribution of the ti-pO2 values show in all the examined time intervals (day 0-6/ 0-72 h/ 0-48 hand 0-24 h) a left shift in the bad outcome group with most pronounced difference for ti-pO2≤ 10 mmHg. For the period from 0-48 h and even more from 0-24 h post-injury, the difference between both groups was significant (p = 0.036 and p = 0.013). In the bad outcome group 35.5% of the values from 0-24 h were ≤ 10 mmHg (compared to 70.6% in the good outcome group. ti-p2 values 250 mmHg were seen more often in the bad outcome group; this occurred mainly after 48–72 h post-injury. The authors concluded that brain ti-p2 monitoring is able to detect the occurrence of early hypoxic insults. Brain ti-p2 monitoring is an important parameter in the multimodality monitoring system. [Neural Res 1998; 20 (Suppl 1): 571–575]