Trauma is a major cause of morbidity and mortality worldwide. Of patients arriving to trauma centers, patients requiring massive transfusion (MT, ≥10 units in 24 hours) are a small patient subset but are at the highest risk of mortality. Transfusion of appropriate ratios of blood products to such patients has recently been an area of interest to both the civilian and military medical community. Plasma is increasingly recognized as a critical component, though less is known about appropriate ratios of platelets. Combat casualties managed at the busiest combat hospital in Iraq provided an opportunity to examine this question.
In-patient records for 8,618 trauma casualties treated at the military hospital in Baghdad more than a 3-year interval between January 2004 and December 2006 were retrospectively reviewed and patients requiring MT (n = 694) were identified. Patients who required MT in the first 24 hours and did not receive fresh whole blood were divided into study groups defined by source of platelets: (1) patient receiving a low ratio of platelets (<1:16 apheresis platelets per stored red cell unit, aPLT:RBC) (n = 214), (2) patients receiving a medium ratio of platelets (1:16 to <1:8 aPLT:RBC) (n = 154), and (3) patients receiving a high ratio of platelets (≥1:8 aPLT:RBC) (n = 96). The primary endpoint was survival at 24 hours and at 30 days.
At 24 hours, patients receiving a high ratio of platelets had higher survival (95%) as compared with patients receiving a medium ratio (87%) and patients receiving the lowest ratio of platelets (64%) (log-rank p = 0.04 and p < 0.001, respectively). The survival benefit for the high and medium ratio groups remained at 30 days as compared with those receiving the lowest ratio of platelets (75% and 60% vs. 43%, p < 0.001 for both comparisons). On multivariate regression, plasma:RBC ratios and aPLT:RBC were both independently associated with improved survival at 24 hours and at 30 days.
Transfusion of a ratio of ≥1:8 aPLT:RBC is associated with improved survival at 24 hours and at 30 days in combat casualties requiring a MT within 24 hours of injury. Although prospective study is needed to confirm this finding, MT protocols outside of investigational research should consider incorporation of appropriate ratios of both plasma and platelets.
From the Walter Reed Army Medical Center (J.G.P., C.P.A., P.W.), Washington DC; Connecticut Children’s Medical Center (P.C.S.), Hartford, Connecticut; United States Army Institute of Surgical Research (L.H.B., C.E.W., J.B.H.), Fort Sam Houston, Texas; Brooke Army Medical Center (K.W.G.), San Antonio, Texas; William Beaumont Medical Center (T.B.R.), El Paso, Texas; Walter Reed Army Institute of Research (L.K.), Silver Spring, Maryland; Madigan Army Medical Center (R.E.L., A.C.B., J.A.S.), Tacoma, Washington; and Washington Hospital Center (A.F.S.), Washington DC.
Submitted for publication November 26, 2008.
Accepted for publication January 16, 2009.
The views and opinions expressed in this manuscript are those of the authors and do not reflect the official policy or position of the Army Medical Department, Department of the Army, the Department of Defense, or the United States Government.
Address for reprints: Jeremy G. Perkins, MD, Walter Reed Army Medical Center, 6900 Georgia Avenue, NW, Washington DC 20307; email: Jeremy.firstname.lastname@example.org.