The Rapid Infusion System (RIS) is a device which can deliver warm fluid and blood products rapidly and at precise rates. It has been in use since 1990 for the management of victims of major trauma at the R Adams Cowley Shock Trauma Center (STC) in Baltimore. Although the RIS is unquestionably a convenience to the anesthesiologist, no study to date has addressed its effect on patient outcome. We have therefore undertaken a retrospective review of all uses of the RIS on trauma patients during the years in which it has been available at the Shock Trauma Center, comparing actual patient mortality both to expected mortality derived from the STC Trauma Registry, and to matched historical controls who did not receive fluids via the RIS. A total of 527 patients were included in the study. The mean volume infused via the RIS was 9724 ml, and the total volumes ranged from 24-117 585 ml. Overall survival was significantly less than expected (52.9% vs. 61.8%, P < 0.001). Survival in penetrating trauma was similar to expected, but in blunt trauma it was considerably less (48.8% vs. 63.0%, P < 0.001). Patients whose probability was between 0.1% and 0.9% also survived significantly less frequently than expected (44.3% vs. 57%, n = 105, P < 0.008). In those patients who received less than 6000 ml via the RIS, the actual and expected survival rates were almost identical. In those receiving more than 6000 ml (180 patients), the difference between actual and expected survival was striking (37.2% vs. 57.2%, P < 0.0001). As compared to matched control patients injured to the same extent during the same time period, patients who received fluids via the RIS had a 4.8 times greater chance of dying (95% confidence interval 2.4-7.1). These data call into question current protocols for rapid volume infusion in trauma management and point to the need for further prospective trials.