The risk factors of venous thromboembolism in massively transfused patients.

BACKGROUND: Massive transfusion protocols (MTPs) are necessary for hemodynamically unstable trauma patients with active bleeding. Thrombotic events have been associated with blood transfusion; however, the risk factors for the development of venous thromboembolism (VTE) in trauma patients receiving MTP are unknown.

METHODS: A retrospective review was conducted by reviewing the electronic medical records of all trauma patients admitted to a Level I trauma center who received MTP from 2011 to 2016. Data were collected on patient demographics, mechanism of injury, injury severity scores, quantity of blood products transfused during MTP activation, incidence of VTE, intensive care unit length of stay (LOS), hospital LOS, and ventilator days. The primary outcome was VTE.

RESULTS: Of the 59 patients who had MTP activated, 15 (25.4%) developed a VTE during their hospital admission. Patients who developed VTE were compared with those who did not. Age (40 y versus 35 y, P = 0.59), sex (60% versus 73% male, P = 0.52), and mechanism of injury (47% versus 59% blunt, P = 0.40) were similar. Intensive care unit LOS, hospital LOS, and ventilator days were longer in the patients who were diagnosed with a VTE. Multivariable analysis revealed an increase in the odds for developing a VTE with increasing packed red blood cell transfusion (adjusted odds ratio = 2.61, P = 0.03).

CONCLUSIONS: The risk for VTE in trauma patients requiring massive transfusion is proportional to the number of packed red blood cells transfused. Liberal screening protocols and maintenance of a high index of suspicion for VTE in these high-risk patients is justified.