TORONTO -- A drink or two may protect against death from a hard blow to the head, researchers here reported.
TORONTO, Dec. 18 -- A drink or two may protect against death from a hard blow to the head, researchers here reported.
They looked at blood alcohol levels in patients with severe traumatic brain injury following blunt head trauma, and found that those with low-to-moderate levels had a lower risk of dying compared with those with either no alcohol in the blood or too much.
"Overall, people are still at much greater risk of dying if they drive while intoxicated," wrote Homer C. N. Tien, M.D, of the University of Toronto, and colleagues in other Canadian centers, in the Dec. issue of Archives of Surgery.
"What our study implies is that there may be a role for an alcohol-based resuscitation fluid in improving outcomes in adequately resuscitated patients with severe head injury."
While alcohol use may lead to car accidents or other mishaps that cause severe head trauma, its effects on traumatic brain injury are unclear, with various studies showing either negative, neutral, or even neuroprotective properties of intoxicating beverages, the authors wrote.
They conducted a retrospective study to determine whether blood alcohol concentrations at admission correlated with in-hospital deaths in patients with traumatic brain injury following blunt head trauma.
They reviewed data from a trauma registry at Sunnybrook and Women's College Health Sciences Center, an urban level I trauma center here.
They identified all patients trauma patients evaluated over a 16-year period, from 1988 to 2003. The patients included all adolescents and adults from the ages of 15 to 90 who had blunt trauma and were brought to the center directly from the accident or injury scene. They also looked at patients with severe blunt trauma to the torso who had little or no head injury for a tracer condition comparison.
Information about patient demographics, mechanism of injury, injury severity scores and abbreviated injury severity scores, length of stay, ICU days, total units of blood transfused and in-hospital outcome were recorded, and the severity scores were calculated by the trauma registry staff after the death or discharge of each patient.
The authors also looked at blood alcohol concentrations in each patient at trauma center arrival, and constructed a histogram plotting mortality versus increasing blood alcohol concentration to see whether there was a possible dose effect of blood alcohol in patients with severe brain injury.
They found that the cutoff point appeared to be at 230 mg/dL: below that level, mortality was lower, and above it deaths were higher. They therefore analyzed survival at three levels of blood alcohol concentration: 0 mg/dL (no blood alcohol), less than 230 mg/dL (low to moderate blood alcohol concentration); and 230 mg/dL or more (high blood alcohol concentration).
They identified 3,675 patients who both met the inclusion criteria and had a known blood alcohol level. In all, 1,158 of these patients had severe traumatic brain injury, and 528 had severe torso injuries with mild or no head injuries.
Nearly two-thirds of the brain injury patients (63.9%) had no blood alcohol, 27.2% had low-to-moderate levels, and 8.9% had a high concentration. Patients with at least some alcohol in their blood were more likely to be male, and men had a higher blood alcohol concentration than women. There were no apparent differences in injury severity scores, blood transfusion requirements, or length of hospital stay among the three blood alcohol concentration groups.
In patients with the tracer condition (severe torso injury), those with at least some level of blood alcohol were likely to be male and younger than patients with no blood levels of booze. Injury severity scores, transfusion requirements, and length of hospital stay were similar for patients with no blood alcohol concentration and with blood alcohol levels of more than 0 mg/dL in the tracer condition patients.
The investigators found that in the patients with severe traumatic brain injury, the overall risk of dying in the hospital was significantly lower in patients with a low to moderate alcohol concentrations compared with none: 27.9% versus 36.3%, respectively (P=0.008).
In contrast, there was a trend among patients with high blood alcohol levels toward higher mortality compared with patients with no blood levels, but this finding did not reach statistical significance (44.7% versus 36.3%; P=0.10). There was also a trend toward earlier in-hospital deaths among patients with high versus no blood alcohol concentration.
"To gauge the robustness of this finding, we analyzed mortality in patients with the tracer condition," the investigators wrote. "As expected, there were no significant differences in mortality between patients with a low blood alcohol concentration compared with no blood alcohol concentration (15.4% versus14.9%; P=0.90) and between patients with a high blood alcohol concentration compared with no blood alcohol concentration (13.0% versus 14.9%; P=1.0)."
As with the severe traumatic brain injury patients, however, there was in the tracer condition a trend toward earlier in-hospital deaths among patients with high blood alcohol levels.
The authors then performed logistic regression analysis, controlling for confounding factors including gender, age, injury severity scores, units of transfused red blood cells, abbreviated injury severity scores (for chest, abdomen, and head and neck), year of admission, and mechanism of injury (occupants of motorized vehicle vs. other).
They found that all of the variables except gender, year of admission, and chest and abdomen injury scores, significantly affected survival, and that blood alcohol concentration at admission was also an independent predictor of death.
The odd ratio for survival with low-to-moderate blood alcohol concentration compared with no blood alcohol was 0.76 (95% confidence interval, 0.52-0.98). In contrast, the odds ratio for a high blood alcohol level versus none was 1.73 (95% CI, 1.05-2.84).
Looking at multivariate models for the tracer condition, they found that neither low nor high blood alcohol concentrations were significant predictors of death.
"Low to moderate blood alcohol concentration may be beneficial in patients with severe brain injury from blunt head trauma," the investigators wrote. "In contrast, high blood concentration seems to have a deleterious effect on in-hospital death in these patients, which may be related to its detrimental hemodynamic and physiologic effects.