Impact of Referring Hospital Imaging on Mortality at a Level I Trauma Center

Computed tomography (CT) has become a standard adjunct in the evaluation of patients with trauma. However, utility of imaging at the referring hospital remains controversial. We study the effect of CT scans at referring hospitals on in-hospital mortality at a receiving trauma center.

A retrospective cohort study was performed with adult patients with severe trauma transferred to a level I trauma center from regional nontrauma hospitals between 2012 and 2017. Baseline characteristics were compared with Student's t-test and Pearson's chi-squared testing. The primary endpoint was in-hospital mortality. Cox regression, controlling for transfer time, was used to evaluate the effect of imaging on mortality.

Three thousand four hundred and fifteen adult patients with trauma were included: 1135 (33.2%) received a pretransfer CT scan, whereas 2280 (66.8%) did not. Patients who received a pretransfer CT scan were more likely to be older, female, white, have a higher Charlson Comorbidity Index, less severely injured, have a blunt mechanism, and be transferred by ground. There was no difference in distance (58.3 miles versus 57.0 miles, P = 0.34), but transfer times were significantly increased for those who received pretransfer scans (288 versus 213 min, P < 0.005). The adjusted model controlling for multiple variables has a hazard ratio of 0.533 (95% confidence interval 0.42-0.68, P < 0.005).

There is a survival advantage for patients who receive pretransfer CT scans despite having significantly longer transport times. We suggest that this decreased mortality associated with pretransfer imaging may reflect improving trends in referring physician transfer decisions.