PAS-C platelets contain less plasma protein, lower anti-A and anti-B titers, and decreased HLA antibody specificities compared to plasma platelets.

BACKGROUND: Platelets (PLTs) collected and stored in PLT additive solution Intersol (PAS-C) are presumed to reduce recipient exposure to donor plasma components; however, the effects of PAS-C on PLT supernatant composition are poorly defined. Therefore, we compared the total protein concentration, isohemagglutinin titers, and HLA antibodies in supernatants of PAS-C PLTs to plasma PLTs. STUDY DESIGN AND METHODS: Apheresis PLTs from group O blood donors were collected into either 100% donor plasma (n = 50) or a mixture of 65% PAS-C/35% donor plasma (n = 50). Within 12 hours of collection, samples of the PLT supernatant were frozen and stored. PLT supernatants were assayed for total protein concentration and anti-A and anti-B titers and screened for HLA antibodies. Samples positive for HLA antibodies were further tested using single-antigen bead assays to determine antibody strength and specificity. RESULTS: Supernatants of PAS-C PLTs had significantly lower total protein concentration and anti-A and anti-B titers compared to plasma PLTs. There was no significant difference in the number of HLA antibody screen-positive PAS-C (3/50) compared to plasma PLT supernatants (2/50); however, the HLA antibody screen-positive supernatants of PAS-C PLTs had fewer HLA specificities (2) compared to those of the plasma PLTs (18). CONCLUSION: Decreased plasma proteins likely underlie lower rates of allergic and febrile, nonhemolytic transfusion reactions from the infusion of PAS-C PLTs. Decreased anti-A and anti-B titers may prevent hemolysis from minor ABO mismatch. Lower HLA antibody specificities may mitigate transfusion-related acute lung injury.

Revisiting early postinjury mortality: are they bleeding because they are dying or dying because they are bleeding?

BACKGROUND: Intense debate continues in the search of the optimal ratio of blood components to deliver preemptively in the critically injured patient anticipated to require a massive transfusion. A major challenge is distinguishing patients with refractory coagulopathy versus those with overwhelming injuries who will perish irrespective of blood component administration. The hypothesis of this clinical study is that a predominant number of early deaths from hemorrhage are irretrievable despite an aggressive transfusion policy. MATERIALS AND METHODS: During the 7-y period ending in December 2009, there were 772 in-hospital trauma deaths. Each of these deaths had been assigned a cause of death via concurrent review by the multidisciplinary hospital trauma quality improvement committee. Emergency department deaths and patients arriving from outside facilities were excluded from this study. RESULTS: Of the 382 patients (49.5% of total) who died secondary to acute blood loss, 84 (22.0%) survived beyond the ED; of these 84, 68 (81%) were male, mean age was 31 y, and 30 (36%) sustained blunt trauma. Cause of death was determined to be exsanguination in 63 (75%), coagulopathy in 13 (15%), metabolic failure in 5 (6%), and indeterminate in 3 patients (4%). CONCLUSION: These data indicate that 75% of patients who succumb to postinjury acute blood loss are bleeding because they are dying rather than dying because they are bleeding. Conversely, only 13 (2%) of the hospital deaths were attributed to refractory coagulopathy. These critical facts need to be considered in designing studies to determine optimal massive transfusion protocols.