To determine the predictive value of the change in hematocrit (Hct) before and after decompressive craniectomy on short-term prognosis of traumatic brain injury patients and to elucidate the influential factors of the delta Hct.

Records of 142 head-injured patients, who underwent unilateral decompressive craniectomy in our hospital, were retrospectively collected between 2013 and 2017. Among them, there were 106 males and 36 females, whose age ranged from 18 to 74 years with the average age of 43.68 years. Multivariate logistic regression analysis was used to determine the factors that affected short-term (within one month) prognosis. Delta Hct (postoperative Hct minus initial Hct) and other factors were applied to predict the 30-day outcome. Sensitivity, specificity and receiver operating characteristic curves were calculated for delta Hct vs. short-term mortality. Multiple linear regression was used to study factors influencing the delta Hct.

The short-term mortality was 29.62%(41/142). Multivariate logistic regression analysis showed that age (OR 1.070 [95% CI 1.026-1.116], P<0.05), GCS score (OR 0.701 [95% CI 0.549-0.894], P<0.05), postoperative Hct (OR 0.841 [95% CI 0.723-0.979], P<0.05) and delta Hct (OR 1.246 [95% CI 1.056-1.471], P<0.05) were independent risk factors for short-term death. Multiple linear regression showed that the ISS score (β=0.263, P<0.05), initial Hct (β=0.373, P<0.05), the time of operation (β=1.268, P<0.05), crystal quantity (β=0.002, P<0.05) and colloid quantity (β=0.002, P<0.05) were independent influential factors of the delta Hct. We found the best critical value of delta Hct was 14% (sensitivity 76.2%, specificity 26.0%, AUC 0.792)and the short-term mortality of decompressive craniectomy patients was 43% if greater than 14%.

The delta Hct, postoperative Hct, GCS score and age are independent risk factors for short-term mortality. By controlling the duration of operation or appropriately diluting blood before operation and administering limited fluid resuscitation, we can lower delta Hct during the operation, which may improve the short-term prognosis for those patients.