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

Abstract

Objective: Anemia and operative blood loss are common in the elderly, but evidence is lacking on whether intraoperative blood transfusions can reduce the risk of postoperative death.

Methods: We analyzed retrospective data from 239,286 patients 65 years of older who underwent major noncardiac surgery in 1997 to 2004 at veteran hospitals nationwide. Propensity-score matching was used to adjust for differences between patients who received intraoperative blood transfusions (9.4%) and those who did not, and data were used to determine the association between intraoperative blood transfusion and 30-day postoperative mortality.

Results: After propensity-score matching, intraoperative blood transfusion was associated with mortality risk reductions in patients with preoperative hematocrit levels of <24% (odds ratio: 0.60, 95% CI: 0.41-0.87), and in patients with hematocrit of 30% or greater when there is substantial (500-999 mL) blood loss (odds ratio: 0.35, 95% CI: 0.22-0.56 for hematocrit levels between 30%-35.9% and 0.78, 95% CI: 0.62-0.97 for hematocrit levels of 36% or greater). When operative blood loss was <500 mL, transfusion was not associated with mortality reductions for patients with hematocrit levels of 24% or greater, and conferred increased mortality risks in patients with preoperative hematocrit levels between 30% to 35.9% (odds ratio 1.29, 95% CI: 1.04-1.60).

Conclusions: Intraoperative blood transfusion is associated with a lower 30-day postoperative mortality among elderly patients undergoing major noncardiac surgery if there is substantial operative blood loss or low preoperative hematocrit levels (<24%). Transfusion is associated with increased mortality risks for those with preoperative hematocrit levels between 30% and 35.9% and <500 mL of blood loss.