A study published in JAMA assessed, “the association between high fresh frozen plasma (FFP) to red blood cell (RBC) transfusion ratio and mortality in patients with severe blunt trauma.” The authors sought to determine, “whether there was a nonlinear relationship between the transfusion ratio and survival to establish the optimal transfusion strategy.” They performed a retrospective analysis of the Japan Trauma Data Bank, “a nationwide, multicenter, prospective, and observational trauma registry established in 2003 [that] collects data on trauma admissions from more than 200 participating hospitals in Japan and is compiled annually.”
For this FFP to RBC transfusion ratio study, the researchers included individuals from the database who suffered severe blunt trauma and required blood transfusion (without a traumatic brain injury (TBI)). They specifically, “targeted patients with blunt trauma and an Injury Severity Score (ISS) of 16 or more [dividing them] into two groups according to their FFP to RBC ratios. [They] defined the exposure of interest as high FFP (FFP to RBC ratio >1) and the comparison as low FFP (FFP to RBC ratio ≤1).”
The authors explained that for the FFP to RBC transfusion ratio study, “[the] primary outcome was all-cause in-hospital mortality. We evaluated the occurrence of transfusion-related adverse events, including pulmonary edema, acute respiratory distress syndrome, pulmonary thromboembolism, pneumonia, acute kidney injury, and sepsis.” The FFP to RBC transfusion ratio study included, “[a] total of 1,954 patients (median [IQR] age, 61 [41-77] years; 711 female[s] [36.4 percent]; 1,243 male[s] [63.6 percent]).” It found that, “transfusions with high-FFP ratios were associated with favorable outcomes. [The authors] observed a nonlinear relationship between the FFP to RBC ratio and in-hospital mortality, suggesting a dose-response relationship between a low ratio and poor outcomes and a ceiling effect in the association between a high ratio and favorable outcomes. This finding suggests the existence of an optimal transfusion ratio. [Additionally, the authors noted that the] primary finding of this FFP to RBC transfusion ratio study was that the transfusion of an FFP to RBC ratio greater than one was associated with a favorable outcome, which is partially different from the current transfusion consensus based on previous randomized controlled trials (RCTs)…Furthermore, this study reflects the latest hemostatic resuscitation trauma treatment strategies, including a massive transfusion protocol and damage control surgery, based on real-world data, with potential confounders carefully controlled and robustness reinforced by several sensitivity analyses.”
The researchers also noted that, “the high ratio of FFP transfusions may be disadvantageous. Although no clear statistical association was demonstrated in this study, [certainly,] high FFP transfusions have been reported to pose risks, such as volume overload and dilution of blood components, which need to be considered carefully. Thus, the trend of complications seen in this study is similar to or emphasized in previous studies, and transfusion of large amounts of FFP without setting an upper limit at a ratio too high for RBC should be avoided. Therefore, it is crucial to determine the optimal transfusion ratio.”
The FFP to RBC transfusion ratio study concluded that, “a high FFP to RBC ratio greater than one was associated with lower in-hospital mortality than a low-FFP ratio in adults with severe blunt trauma; however, there may be a ceiling effect at a ratio of more than 1.5. Future RCTs focusing on blunt trauma are warranted to demonstrate the efficacy of high FFP ratios in trauma settings.” Limitations of the study included, “the number of patients with severe trauma requiring transfusion was limited due to the decline in the number of trauma cases, [the study] could not adjust for time-dependent confounding factors owing to the lack of data over time after the hospital visit, [and] there are concerns about external validity in other countries owing to differences in trauma care.” An “Invited Commentary” has also been published in JAMA.
Citation: Fujiwara, G., Okada, Y., Ishii, W, et al. “High fresh frozen plasma to red blood cell ratio and survival outcomes in blunt Trauma.” JAMA. 2024