10th September 2015: Transfusion of Plasma, Platelets, and Red Blood Cells in a 1:1:1 vs a 1:1:2 Ratio and Mortality in Patients With Severe Trauma.

Presented by Dr Andy Conway Morris

When we manage patients following major trauma we want to maintain tissue perfusion, ensure adequate tissue oxygen delivery, and stop any bleeding. The use of intravenous fluids is almost ubiquitous and yet it remains one of the more poorly examined areas of practice while the evidence which does emerge (in this example – sepsis) gives cause for concern that fluids may carry unappreciated risk. Confronted with a hypovolaemic patients, most of us will reach for crystalloid in the first instance, which whilst convenient and immunologically inert can impair both oxygen delivery and coagulation through the dilution of red cells, platelets and clotting factors. The most physiologically optimal replacement fluid would be fresh, whole blood and indeed its use appears to be associated with better outcomes, however for many reasons this is not a practicable solution in most situations and we must rely on stored blood components (red cells, plasma and platelets).

How we should use blood products to resuscitate trauma patients has been the subject of considerable debate, and until recently was largely informed by observational data. The desire to achieve something close to reconstituted whole blood led to the initiation of 1:1:1 ratios of red cells, plasma and platelets as empiric therapy in trauma. Although mathematically simple, actual use of this ratio will not recreate whole blood due to the effects of dilution of components with storage anticoagulant solutions (See, for example, this review). The subsequent observational studies which indicated a benefit of this ratio are heavily influenced by survivor bias – patients who died tended to die before they had time to receive significant amounts of non-RBC components and were more severely injured (discussed here and here).

It is not news anymore to state that trauma coagulopathy is linked to a range of important outcomes (links in one of our previous journal clubs which are essential reading for this journal club), nor is it news that recent military experience led to the concept of early use of non-rbc blood components to maximise haemostasis, with this being done on an empiric and protocolised basis, rather than in reaction to laboratory parameters of coagulation. What isn’t clear, however, is what the ratio should be.

Into this fraught area comes this study, which we will discuss at journal club, of 1:1:1 vs 1:1:2 transfusion ratios of plasma, platelets, and RBCs in patients with major trauma who were deemed to be at risk of massive blood transfusion.  An important study and at journal club we should discuss whether there is enough evidence now to move to a strategy of 1:1:1. We should, however, first know our current protocol and whether there have been any audits in Cambridge to examine if we meet our current ratio guidelines.

Other questions, to guide the discussion, include:

  • Are we even close to 1:1:2 in early resuscitation the UK, would we need pre-thawed AB plasma for this (as an aside why do we need AB)
  • Has this study simply shown the need for platelets (40% of 1:1:2 randomised patients received no platelets)
  • Is there a role for crystalloid in patients who are bleeding?
  • Are these results generalisable to to patients bleeding in non-major trauma situations (e.g. GI bleeding, vascular haemorrhage, obstetrics) ?

This study has been extensively discussed in various places, some of which are linked below:

In the video above Prof Steve Barnes discusses the background to trauma coagulopathy and rationale for the increased ratio of FFP and platelets

John Holcombe has been interviewed by Scott Weingart of EMCrit here.

Excellent, critical appraisal of the study by the Wessex ICS Bottom Line blog.

Skeptics guide to EM blog

The adventure of the blanched soldier