Where are we going to get all these blood products? The rapidly growing body of literature backing early transfusion of FFP and platelets in massive transfusion protocols continues to tilt towards the 1:1:1 ratio.
This is a retrospective review of whether platelet transfusion impacts survival in trauma. They identify three categories of ratios of platelets to RBCs (>1:20, 1:2, and 1:1) and measure a variety of different outcomes. Briefly, more platelets helped with survival to 24 hours, but more platelets also increased multi-organ failure. In the end, the initial survival differences were great enough that they outweighed the additional multi-organ failure for a significant survival benefit (52% vs. 57% vs. 70%).
They exclude 25 patients who died within an hour in an effort to mitigate survival bias. However, looking at the breakdown of survival times, it looks as though almost all the mortality benefit to increased platelet ratios was realized in the first 6 hours – and then the mortality numbers worsen in tandem after that. The authors state they were unable to truly quantify retrospectively whether the patients survived because they received more platelets vs. whether patients surviving longer were able to receive more platelets, and note that prospective trials will need to be performed.
I would also note that a significant portion of their high ratio patients also received Factor VII, for whatever that’s worth.
So, we continue to await high quality prospective trials that specifically address the impact of survival bias.
“Increased Platelet:RBC Ratios Are Associated With Improved Survival After Massive Transfusion.”
http://journals.lww.com/jtrauma/Abstract/2011/08003/Increased_Platelet_RBC_Ratios_Are_Associated_With.2.aspx