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

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. 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. 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). 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.