ANH Reduces Need for Transfusion but Remains Underused, Study Suggests

Acute normovolemic hemodilution (ANH) was associated with 27% lower odds of any transfusion among patients undergoing surgery with cardiopulmonary bypass, but remains underused, according to research published Sept. 3 in JAMA Surgery.

In the retrospective study, a research team from the University of Oklahoma reviewed data from 16,795 patients in the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database. Among these patients, 2,463 (14.7%) received ANH, a blood conservation technique that involves removing blood before bypass and reinfusing it after surgery.

After propensity score matching, 31.2% of patients in the ANH group received a transfusion, compared with 36.4% of patients who did not undergo ANH. High-volume ANH (defined as 650 mL or greater) also reduced the odds of transfusion by 47% to 64% for both RBC and non-RBC components. Notably, the cumulative number of transfused erythrocyte and platelet units was 167 and 295 units lower, respectively, in the ANH group compared with the control group.

According to Kenichi Tanaka, MD, the study’s lead author, the findings suggest that ANH may be a valuable tool in helping hospitals improve resource utilization without negatively affecting patient outcomes.

“We know that patients receiving ANH have survival rates and duration of hospitalization similar to those who receive transfusions, but I believe we are improving resource utilization by performing ANH,” Tanaka said. “That is especially true when we take a bleeding patient to the ICU, where we tend to use more resources, therefore leading to higher costs.”

The findings contrast those from an international study published in the New England Journal of Medicine and also led by Tanaka, In this study, Tanaka and his co-investigators  found that ANH did not reduce the need for RBC transfusions. However, the researchers emphasized that less than 5% of participants in this trial were from the United States and the findings may not be fully generalizable to U.S. practice.