Platelet Transfusion and Outcomes After Massive Transfusion Protocol Activation for Major Trauma: A Retrospective Cohort Study

BACKGROUND: Incorporation of massive transfusion protocols (MTPs) into acute major trauma care has reduced hemorrhagic mortality, but the threshold and timing of platelet transfusion in MTP are controversial. This study aimed to describe early (first 4 hours) platelet transfusion practice in a setting where platelet counts are available within 15 minutes and the effect of early platelet deployment on in-hospital mortality. Our hypothesis in this work was that platelet transfusion in resuscitation of severe trauma can be guided by rapid turnaround platelet counts without excess mortality. METHODS: We examined MTP activations for all admissions from October 2016 to September 2018 to a Level 1 regional trauma center with a full trauma team activation. We characterized platelet transfusion practice by demographics, injury severity, and admission vital signs (as shock index: heart rate/systolic blood pressure) and laboratory results. A multivariable model assessed association between early platelet transfusion and mortality at 4 hours, 24 hours, and overall in-hospital, with P <.001. RESULTS: Of the 11,474 new trauma patients admitted over the study period, 469 (4.0%) were massively transfused (defined as ≥10 units of red blood cells [RBCs] in 24 hours, ≥5 units of RBC in 6 hour, ≥3 units of RBC in 1 hour, or ≥4 units of total products in 30 minutes). 250 patients (53.0%) received platelets in the first 4 hours, and most early platelet transfusions occurred in the first hour after admission (175, 70.0%). Platelet recipients had higher injury severity scores (mean ± standard deviation [SD], 35 ± 16 vs 28 ± 14), lower admission platelet counts (189 ± 80 × 109/L vs 234 ± 80 × 109/L; P < .001), higher admission shock index (heart rate/systolic blood pressure; 1.15 ± 0.46 vs 0.98 ± 0.36; P < .001), and received more units of red cells in the first 4 hours (8.7 ± 7.7 vs 3.3 ± 1.6 units), 24 hours (9 ± 9 vs 3 ± 2 units), and in-hospital (9 ± 8 vs 3 ± 2 units) than nonrecipients (all P < .001). We saw no difference in 4-hour (8% vs 7.8%; P = .4), 24-hour (16.4% vs 10.5%; P = .06), or in-hospital mortality (30.4% vs 23.7%; P = .1) between platelet recipients and nonrecipients. After adjustment for age, injury severity, head injury, and admission physiology/laboratory results, early platelet transfusion was not associated with 4-hour, 24-hour, or in-hospital mortality. CONCLUSIONS: In an advanced trauma care setting where platelet counts are available within 15 minutes, approximately half of massively transfused patients received early platelet transfusion. Early platelet transfusion guided by protocol-based clinical judgment and rapid-turnaround platelet counts was not associated with increased mortality.