Operative blood loss, blood transfusion and 30-day mortality in older patients after major noncardiac surgery

Question: In elderly patients with variable preoperative anemia and volume of blood loss during major noncardiac surgery, does intraoperative blood transfusion reduce the risk of perioperative death? Design: Retrospective cohort study. Data source: National Surgical Quality Improvement Program database. Patients: Veterans aged 65 years or older with a documented preoperative hematocrit (HCT) value who underwent major noncardiac surgery between 1997 and 2004. Methods: Propensity score matching was used to adjust for differences between patients who received intraoperative blood transfusions (9.45) and those who did not. Main outcome: Association between intraoperative blood transfusion and 30-day postoperative mortality. Results: After propensity score matching, intraoperative blood transfusion was associated with mortality risk reduction in patients with preoperative HCT levels lower than 24% (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.41–0.87) and in patients with HCT of 30% or greater who experienced substantial (500–999 mL) blood loss (OR 0.35, 95% CI 0.22–0.56 for HCT levels between 30% and 35.9%, and OR 0.78, 95% CI 0.62–0.97 for HCT levels of 36% or greater). When operative blood loss was less than 500 mL, transfusion was not associated with mortality reductions for patients with HCT levels of 24% or greater and conferred increased mortality risks in patients with preoperative HCT levels between 30% and 35.9% (OR 1.29, 95% CI 1.04–1.60). Conclusion: Intra-operative blood transfusion was associated with lower 30-day postoperative mortality among elderly patients undergoing major noncardiac surgery if there was substantial operative blood loss or low preoperative HCT levels (< 24%). Transfusion was associated with increased risk of death for those with preoperative HCT levels between 30% and 35.9% and less than 500 mL of blood loss.