[1/1 plasma to red blood cell ratio: an evidence-based practice?]

Coagulopathy during massive haemorrhage increases morbidity and mortality rates. The modalities of treatment by transfusion of fresh frozen plasma (FFP) are a matter of debate. According to most clinical practice guidelines, FFP administration is driven by coagulation tests but, in cases of massive transfusion, patient management may be delayed whilst awaiting results and thawing FFP. Several retrospective cohort studies of military or civilian multiple trauma casualties requiring massive transfusion (>10 red blood cells (RBC) within 24h) have suggested that early use of FFP and high FFP:RBC ratios (approaching 1) might improve survival and lessen morbidity. However, the methodology of these studies is suboptimal. They are subject, in particular, to survival bias. Massive FFP transfusions can also lead to an enhanced incidence of transfusion-related acute lung injury (TRALI), acute respiratory distress syndrome (ARDS), and multi-organ failure. At the present time, it is clear that FFP transfusion should be initiated early with a high FFP:RBC ratio in massive bleeding associated with haemostatic abnormalities such as multiple trauma. This does not imply that such a recommendation can be extended to the correction of high blood loss in other situations such as scheduled surgery. Actually, very few patients are likely to derive benefit from a 1/1 FFP:RBC transfusion strategy. They are chiefly multiple trauma victims with haemorrhagic shock and cases of ruptured abdominal aortic aneurysm. In other patients, in order to minimize risks and costs, a more parsimonious FFP use policy remains the best option until evidence for the benefit of 1/1 FFP:RBC is demonstrated.