Injured patients have lower mortality when treated by "full-time" trauma surgeons vs. surgeons who cover trauma "part-time"

Background. Studies examining the effect of trauma surgeon volume on patient outcomes have had disparate results. We hypothesize that "full-time" trauma surgeons would have lower patient mortality rates than surgeons covering trauma "part-time." Methods. Retrospective review of 14,171 patients during a span of 6.5 years (January 1998 to June 2004) from the trauma registry at an urban, university-based Level I trauma center. "Full-time" surgeons practiced primarily trauma, emergency surgery, and critical care. "Part-time" surgeons took trauma call, but mainly practiced another type of surgery (e.g., pancreatic, hepatobiliary, vascular, transplant). Chi square and multiple logistic regression compared mortality between groups. Results. There were no differences in patient demographics or admission injury patterns between the two groups. On bivariate analysis, the subgroup of patients with severe head injury had lower mortality when treated by "full-time" surgeons. With ED deaths excluded, more severely injured patients (Injury Severity Score [ISS] > 15) had a survival benefit in the "full-time" group. Multiple logistic regression showed a 50% increase in mortality for patients treated by "part-time" trauma surgeons when adjusting for age, sex, ISS > 15, severe head injury, hypotension, nighttime admission, day of the week, and penetrating mechanism (odds ratio of death 1.45, 95% CI 1.04-2.02). Similar results are seen in only patients surviving to emergency room discharge (odds ratio of death 1.50, 95 % CI 1.01-2.22). Z and W scores showed higher than expected survival for all patients with the "full-time" cohort showing a larger benefit. Conclusion. Even within an established trauma program treating many injured patients, mortality is significantly lower in patients initially treated by "full-time" trauma surgeons.