International Study Finds Blood Conservation Technique Does Not Lower Transfusion Needs During Heart Surgery

A recent international clinical trial published in the New England Journal of Medicine examined the effectiveness of acute normovolemic hemodilution (ANH), a blood conservation method used in heart surgeries. ANH involves removing a patient's blood before their heart-lung machine surgery and reinfusing it later. Although this technique has been debated for its potential to reduce blood transfusions, the study's findings suggest that ANH does not significantly decrease the need for red blood cell transfusions in patients undergoing surgery.

Led by researchers from multiple countries, including the US, Europe, Asia, and South America, the trial included 2,010 patients across 11 nations and assessed whether ANH could minimize transfusions, which come with risks such as complications, high costs, and blood shortages. Surprisingly, the results showed no substantial reduction in transfusion requirements among patients who received ANH.

Kenichi Tanaka, M.D., a co-leader of the study and chair of anesthesiology at the University of Oklahoma, emphasized that these outcomes warrant further investigation and may not be directly applicable to U.S. healthcare settings. Factors such as the smaller average body size of U.S. patients, variations in transfusion protocols, and the use of clotting factor concentrates could influence the effectiveness of ANH. Notably, U.S. centers participate in the study only modestly, with less than 5% of participants from the U.S.

Despite the findings, Dr. Tanaka suggests that ANH might still be beneficial in specific contexts, such as for Jehovah’s Witness patients who refuse blood transfusions, or as part of a comprehensive blood conservation strategy. He is also preparing a retrospective study indicating that ANH could reduce transfusion needs in U.S. populations.

Overall, the study underscores the complexity of blood management in cardiac surgery and highlights the need for tailored approaches based on patient demographics and institutional practices. While ANH may not universally reduce transfusions, it remains a potential tool within a multifaceted blood conservation program.

Source: https://medicalxpress.com/news/2025-06-blood-technique-transfusions-international.html