Safety of ultra-permissive anemia within a cardiac surgery patient blood management program

There remains a lack of studies assessing the safety of highly restrictive patient blood management in cardiac surgery. Our patient blood management program has been focused on ultra-permissive anemia, tolerating hemoglobin concentrations 6.0 g/dL or more in nonbleeding patients. We reviewed our results following an ultra-permissive anemia strategy regarding blood transfusion rates and the association with major complications after cardiac surgery.

Consecutive patients undergoing coronary artery bypass grafting managed with ultra-permissive anemia were compared with historical controls, labeled the pre-ultra-permissive anemia group, who were transfused at the discretion of the clinician. A 1:1 propensity score matching was performed, and the groups were compared for blood transfusion rates, major complications, length of stay, and cost.

A total of 1216 patients were analyzed. Patients in the ultra-permissive anemia group received significantly less packed red blood cells and other blood components. The mean intraoperative and postoperative packed red blood cells transfusion rates were significantly lower in the ultra-permissive anemia cohort, 2% and 12% versus 27% and 29% pre-ultra-permissive anemia (P < .001). Postoperative length of stay was reduced for patients with ultra-permissive anemia (6.0 days vs 7.3, P < .001). Early extubation rates were higher for patients with ultra-permissive anemia (78% vs 53%, P < .001). The incidence of stage 1 acute kidney injury was lower for patients with ultra-permissive anemia compared with pre-ultra-permissive anemia (20% vs 26%, P = .049) as were rates of atrial fibrillation (34% vs 41%, P = .013). All other major complications, including mortality, were similar.

Our data suggest that ultra-permissive anemia, tolerating hemoglobin values as low as 6 g/dL, is safe and significantly reduces overall blood use.