Impact of early positive cultures in the elderly with traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in the United States, especially in the elderly, who have the highest rates of TBI-related hospitalizations and deaths among all age groups. Sepsis is one of many risk factors that is associated with higher mortality and longer length of hospital stay in this population partially due to the immunosuppressive effects of TBI. The significance of early indicators of infection, such as a positive blood, sputum, or urine culture, is not well described. The purpose of this study was to determine if early positive cultures predict higher mortality in elderly patients with TBI.

All trauma patients aged ≥65 years with TBI, admitted between January 1, 2009 and December 31, 2013 to the surgical intensive care unit, were retrospectively reviewed. Clinical data including results from sputum, blood, and urine cultures were reviewed.

Overall, 288 elderly patients with TBI were identified, and 92 (32%) had a positive culture. Patients with positive cultures had longer intensive care unit (median 6.0 versus 2.0 days, P < 0.001) and ventilation days (median 7.0 versus 2.0 days, P < 0.001). Patients who had positive cultures within 2-3 days of admission had a higher adjusted hazard ratio for mortality than those patients who had positive cultures after 6 or more days.

In elderly patients with TBI, early positive cultures are associated with a higher risk of mortality. Further research is required to determine the role of obtaining cultures on admission in this subpopulation of trauma patients.