Haemostatic resuscitation of trauma patients, using high ratios of fresh frozen plasma (FFP) to packed red cells (PRBC), is growing in popularity as a result of military experience. Few data support the practice in civilian trauma. It is possible that some of the demonstrated mortality benefit is a result of survival bias: it takes time to obtain FFP, by which time severely injured patients may be dead. Therefore, those that receive large ratios of FFP:PRBC must have survived long enough to receive it. In other words FFP doesn’t lead to survival, but survival leads to FFP. Some evidence in favour of this explanation is provided on a study of 134 patients in the Journal of Trauma. Reanalysing data to correct for survival bias made an apparently significant survival benefit from high FFP:PRBC ratios go away. An interesting paper, although unlikely to dissuade us from paying attention to coagulopathy in trauma. I suspect the debate on optimal blood product resuscitation will be around for a while.
The Relationship of Blood Product Ratio to Mortality: Survival Benefit or Survival Bias?
J Trauma. 2009 Feb;66(2):358-62