Traumatic Brain Injury Outcome Associations With Computed Tomography and Glasgow Coma Scale Score Interactions: A Retrospective Study.

Abstract

Background Numerous investigators have shown that early postinjury Glasgow Coma Scale (GCS) values are associated with later clinical outcomes in patients with traumatic brain injury (TBI), in-hospital mortality, and post-hospital discharge Glasgow Outcome Scale (GOS) results. Following TBI, early GCS, and brain computed tomography (CT) scores have been associated with clinical outcomes. However, only one previous study combined GCS scores with CT scan results and demonstrated an interaction with in-hospital mortality and GOS results. We aimed to determine if interactive GCS and CT findings would be associated with outcomes better than GCS and CT findings alone. Methodology Our study included TBI patients who had GCS scores of 3-12 and required mechanical ventilation for ≥five days. The GCS deficit was determined as 15 minus the GCS score. The mass effect CT score was calculated as lateral ventricular compression plus basal cistern compression plus midline shift. Each value was 1 for present. A prognostic CT score was the mass effect score plus subarachnoid hemorrhage (2 if present).The CT-GCS deficit score was the sum of the GCS deficit and the prognostic CT score. Results One hundred and twelve consecutive TBI patients met the inclusion criteria. Patients with surgical decompression had a lower GCS score (6.0±3.0) than those without (7.7±3.3; Cohen d=0.54). Patients with surgical decompression had a higher mass effect CT score (2.8±0.5) than those without (1.7±1.0; Cohen d=1.4). The GCS deficit was greater in patients not following commands at hospital discharge (9.6±2.6) than in those following commands (6.8±3.2; Cohen d=0.96). The prognostic CT score was greater in patients not following commands at hospital discharge (3.7±1.2) than in those following commands (3.1±1.1; Cohen d=0.52). The CT-GCS deficit score was greater in patients not following commands at hospital discharge (13.3±3.2) than in those following commands (9.9±3.2; Cohen d=1.06). Logistic regression stepwise analysis showed that the failure to follow commands at hospital discharge was associated with the CT-GCS deficit score but not with the GCS deficit. The GCS deficit was greater in patients not following commands at three months (9.7±2.8) than in those following commands (7.4±3.2; Cohen d=0.78). The CT-GCS deficit score was greater in patients not following commands at three months (13.6±3.1) than in those following commands (10.5±3.4; Cohen d=0.94). Logistic regression stepwise analysis showed that failure to follow commands at three months was associated with the CT-GCS deficit score but not with the GCS deficit. The proportion not following commands at three months was greater with a GCS deficit of 9-12 (50.9%) than with a GCS deficit of 3-8 (21.1%; odds ratio=3.9; risk ratio=2.1). The proportion of not following commands at three months was greater with a CT-GCS deficit score of 13-17 (56.0%) than with a CT-GCS deficit score of 4-12 (18.3%; OR=5.7; RR=3.1). Conclusion The mass effect CT score had a substantially better association with the need for surgical decompression than did the GCS score. The degree of association for not following commands at hospital discharge and three months was greater with the CT-GCS deficit score than with the GCS deficit. These observations support the notion that a mass effect and subarachnoid hemorrhage composite CT score can interact with the GCS score to better prognosticate TBI outcomes than the GCS score alone.