There is a large, multi-center prospective trial underway attempting to determine the optimal ratio of blood products – testing PRBC:FFP:platelets in 1:1:1 vs. 2:1:1 – because there are concerns especially with complications & costs associated with increasing FFP and platelet transfusions. This article describes a single-center, prospective study of the feasibility of even implementing a 1:1:1 ratio, given the difficulty of having plasma products on hand – but has the interesting side effect of providing some rather interesting and unexpected comparative outcomes data.
These authors enrolled, over a two year period, 78 patients from a pool of 203 screened for eligibility, and randomized them in unblinded fashion to 1:1:1 fixed ratio transfusion or their "usual care" control. "Usual care" for this institution consists of transfusion product balance guided by laboratory results (Hgb, INR, PTT, and fibrinogen). They found, as the primary outcome of their study, that the 1:1:1 ratio was feasible – but resulted in over twice as many wasted units of FFP (22% vs. 10% of thawed units).
The secondary outcomes reported include coagulation monitoring targets and mortality data. There was, for the most part, no statistically significant difference in any reported outcome. The coagulation monitoring targets all had p-values ranging from 0.4 to 0.8 and, truly, are not different. The mortality data, on the other hand, showed 29.7% mortality in the 1:1:1 group and 9.4% mortality in the usual care group – 20.3% difference (95% CI 2.5 to 38.2).
This is not practice-changing evidence. It's a small sample size data coming from secondary outcomes in a feasibility study. But, regardless, it is very interesting to see.
"Effect of a fixed-ratio (1:1:1) transfusion protocol versus laboratory-results–guided transfusion in patients with severe trauma: a randomized feasibility trial"