Review of massive transfusion protocols in the injured, bleeding patient

Massive haemorrhage is a significant cause of mortality and morbidity in a variety of clinical settings, although most research has been related to trauma patients. Military studies from recent conflicts found that higher ratios of plasma to red blood cells (RBCs) were associated with increased survival in injured soldiers, and subsequent trials in civilian populations showed similar decreased mortality. Over the last decade, massive transfusion protocols (MTPs) have become an important component in the treatment of the massively bleeding patient. This review is intended to summarize the more recent findings and trends in massive transfusion.

There have been several observational studies suggesting that higher ratios of plasma to RBC and platelets to RBC are associated with improved survival but there is a paucity of randomized studies relating to specific ratios, dosages, timing, and guidance. Other studies have developed and assessed scoring systems used to initiate MTPs and specific tests used to guide MTPs. Finally, the specific blood components and adjuncts that constitute a MTP are the subject of further ongoing research.

The absence of a universal definition of massive bleeding or massive transfusion, heterogeneity in patients suffering from massive bleeding, and the difficulty in predicting which patients will require a massive transfusion all contribute to the difficulty of studying massive transfusion. However, there is evidence that higher plasma : RBC ratios correlate with improved survival, and that adjuncts to transfusion play a key role. Furthermore, recent validations of massive haemorrhage scoring systems should allow more consistent and appropriate triggering of massive transfusions.