Systematic review of plasma to packed red blood cell ratio on survival in ruptured abdominal aortic aneurysms.

Abstract Background The ideal perioperative fluid resuscitation for ruptured abdominal aortic aneurysms (rAAA) is unknown. It has been shown in the trauma literature that a higher ratio of plasma and platelets to packed red blood cells confers a mortality benefit. There remains controversy whether this is true also in the ruptured aneurysm population. The objective of this study is to investigate the benefit of higher ratio of plasma to packed red blood cells in patients with ruptured abdominal aortic aneurysms. Methods A health sciences librarian searched four electronic databases including PubMed, Embase, Cochrane, and ClinicalTrials.gov using concepts for the terms fluid resuscitation, survival, and ruptured abdominal aortic aneurysm. Two reviewers independently screened the studies that were identified through the search strategy and read in full any study that was potentially relevant. Papers were included if they compared mortality of patients with rAAA who received a higher ratio of plasma to other component therapy to patients who received a lower ratio. Risk of bias was assessed using the ROBINS-I validated tool and evidence quality was rated using the GRADE profile. No data synthesis or meta-analysis was planned or performed given the anticipated paucity of research on this topic and the high degree of heterogeneity of available studies. Results Our search identified seven observational studies to be included in this review. Of these seven studies, three found an associated decrease in mortality with a higher ratio of plasma to packed red blood cells and the remaining four found no significant difference. The overall risk of bias was serious and the evidence quality was very low. Conclusions Overall, the available studies would suggest that for patients that have undergone open surgery for a ruptured abdominal aortic aneurysm, mortality rates tend to decrease when the amount of plasma transfused perioperatively is similar to the amount of packed red blood cells. However, this is very low-quality evidence based solely off of highly heterogenous observational studies and further research is warranted.