Association of Preoperative Blood Transfusion on Postoperative Outcomes in Emergency General Surgery.

INTRODUCTION: Emergency general surgery (EGS) patients often present with anemia, in which preoperative transfusions are performed to mitigate anemia-associated risks. However, transfusions have also been noted to cause worse postoperative outcomes. This study examined how transfusion-associated outcomes vary at different levels of anemia. MATERIALS AND METHODS: The American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2019 was used to identify patients who had undergone any of 12 major EGS procedures using Current Procedural Terminology codes. Patients were divided into two cohorts based on receipt of preoperative transfusion. Cohorts were subdivided into anemia severity levels and propensity score-matched within each using patient demographic and comorbidity variables. We analyzed 30-day postoperative outcomes, including morbidity, mortality, and return to odds ratio (OR), using univariate Chi-squared tests, Wilcoxon signed-rank tests, and multivariate logistic regression analyses. RESULTS: 595,407 EGS cases were identified. Receiving preoperative transfusion were 44.45% (n = 3058) of severely anemic, 10.94% (n = 9076) of moderately anemic, 1.34% (n = 1370) of mildly anemic, and 0.174% (n = 704) of no anemia patients. Transfusion resulted in an increased overall morbidity in the severe (OR 1.54), moderate (OR 1.50), mild (OR 1.71), and no anemia (OR 1.85) groups. Mortality increased in the moderate (OR 1.27), mild (OR 1.61), and no anemia (OR 1.76) subgroups. In severe anemia, transfusion status and mortality were not significantly associated. CONCLUSIONS: Transfusion is associated with higher morbidity and mortality rates in those with higher hematocrit levels, even after controlling for pre-existing comorbidities. A restrictive transfusion strategy should be considered to avoid risks for those with a hematocrit level more than 24%.