Introduction Studies suggest that females fare worse than males after traumatic brain injury (TBI). To investigate whether gender differences in cerebral blood flow (CBF) could affect TBI outcome, we studied CBF, metabolism, and outcomes of 90 male (mean age 35.8±16.3; mean GCS=6.2) and 26 female trauma patients (mean age 39.6±22.7; mean GCS=6.8).
Methods Patients from Los Angeles and Haifa, Israel were consented for CBF measurement and arterial-jugular venous sampling. Studies were conducted from postinjury days 0 to 9. Univariate and multivariate analyses were performed on subjects stratified into 4 age groups (under 25, 25–44, 45–59, and over 59 years).
Results In females, a trend of decreasing CBF with increasing age was observed, reaching significance between youngest and oldest age groups (47.1 to 31.8 mg/100g/min, respectively; p=0.004). Mean GOS scores also decreased with increasing age (youngest:oldest=3.9 to 1.6; p=0.02). However, association of outcome and age may be partially explained by CBF (p=0.3 for age-outcome association after controlling for CBF). In contrast to females, males showed only slight decreases in CBF with increasing age (youngest:oldest= 39.2: 36.7 mg/100g/min; p=0.44). GOS followed a similar trend (youngest:oldest=3.2: 3.0; p=0.92). No differences were found between gender for hematocrit, hemoglobin, or intracranial pressure.
Conclusion Increasing age appears to affect female trauma patients more adversely than males. CBF decreased significantly among older females compared to younger, but CBF in male patients decreased only slightly with age. Outcome followed similar patterns to CBF. Gender differences in CBF may help explain the disparity in outcome after TBI between males and females.