Intraoperative Fresh Frozen Plasma-to-Red Blood Cell Ratio and Postoperative Pulmonary Infection in Adult Liver Transplantation: A Retrospective Cohort Study

Abstract Introduction: The clinical relevance of the intraoperative fresh frozen plasma (FFP)-to-red blood cell (RBC) transfusion ratio during adult liver transplantation (LT) is uncertain. We evaluated its association with postoperative pulmonary infection and 365-day mortality. Methods: We retrospectively analyzed adults undergoing first LT from January 2021 through December 2023 who received at least 1 U of intraoperative RBC. Patients were grouped by FFP:RBC ratio (≤1 vs. >1). Pulmonary infection was obtained from the pre-existing transplant registry; child-field -1 codes were decoded using the parent early-complication field, with manual reconciliation of the sole discordant record. Logistic regression was adjusted for MELD score and blood loss. Mortality was analyzed with Kaplan-Meier and Cox methods. Results: Among 149 patients, 84 had a ratio ≤1 and 65 had a ratio >1. The high-ratio group had lower preoperative fibrinogen and higher INR. Pulmonary infection occurred in 5/84 versus 11/65 patients (Fisher p=0.059; crude OR 3.22, 95% CI 1.06-9.79; p=0.039). The adjusted OR was 3.68 (95% CI 1.16-11.70; p=0.027). Twenty-one deaths occurred within 365 days; the adjusted HR was 1.38 (95% CI 0.57-3.35; p=0.478). Conclusion: A ratio >1 was associated with higher pulmonary-infection odds in crude and parsimonious adjusted logistic models, while the Fisher exact comparison was borderline. Sparse events, outcome-classification uncertainty, and confounding by indication preclude causal or safety conclusions. LT transfusion should remain individualized.