Change in cerebrovascular resistance as diagnostic index of cerebral hemodynamics in patients with severe combined traumatic brain injury

Abstract

The aim of the investigation was to evaluate changes in cerebrovascular resistance (CVR) in severe combined traumatic brain injury (CTBI) against the background of intracranial hematoma development and its role in diagnosing the state of cerebral hemodynamics. Materials and methods. Treatment outcomes in 70 patients with severe CTBI (42 males and 28 females) were studied. Mean age was 35.5±14.8 years (from 15 to 73 years). Depending on the presence of intracranial hemorrhage, the patients were divided into two groups: group 1 — without hematomas, group 2 — with hematomas. The severity of condition according to the Glasgow coma scale in group 1 averaged 10.4±2.6 scores, in group 2 it was 10.6±2.8. The severity of injuries according to ISS scale was 32±8 and 31±11 scores, respectively. Epidural hematomas in group 2 were revealed in 6 persons, subdural ones were found in 26, there were multiple hematomas in 4 patients. All the sufferers underwent surgery within the first three days, 30 patients (83.3%) were operated on for hematomas during the first day. All the patients underwent perfusion CT examination of the brain, transcranial doppler of both middle cerebral arteries, their mean arterial pressure was measured. Relying on these data, cerebral perfusion pressure and CVR (cerebrovascular resistance) were calculated. Results. The mean CVR values in each group (both with and without hematomas) appeared to be statistically significantly higher than the mean normal value of this parameter. Intergroup comparison of CVR values showed statistically significant increase in the CVR level in group 2 on the side of removed hematoma (p=0.037). Cerebrovascular resistance in the perifocal zone of removed hematoma remained significantly higher compared to the symmetrical zone in the contralateral hemisphere (p=0.0009). Conclusion. Cerebrovascular resistance in patients with combined traumatic brain injury is significantly increased compared to the normal value and remains significantly elevated after evacuation of hematoma in the perifocal zone compared to the symmetrical zone in the contralateral hemisphere. This is indicative of certain correlation between the mechanisms of cerebral blood flow autoregulation and maintaining CVR.