Predictors of Cardiac Surgery Patients who Tolerate Blood Conservation

BACKGROUND:

Cardiac surgical patient population that does not incur harm from blood conservation is unknown. This study aimed to identify patient characteristics associated with patients who safely tolerate blood conservation.

METHODS:

We conducted a retrospective review of consecutive patients undergoing isolated coronary artery bypass grafting (CABG), isolated aortic valve replacement (AVR), concomitant CABG and AVR between 2011-2016, during which blood conservation intervention tool place. Logistic regression derived from pre-intervention cohort was applied to post-intervention cohort to identify patient characteristics associated with those predicted to be transfused in pre-intervention era but were not in the post-intervention era.

RESULTS:

In this series of 2,701 adult patients undergoing cardiac surgery, blood conservation intervention in 2014 led to a 52% reduction in red blood cell transfusion. Between pre and post-intervention cohorts, there was no significant difference in the measured outcomes. Regression model derived from pre-intervention cohort was applied to post-intervention cohort to identify predictors of cohort that do not derive benefit from liberal transfusion. This demonstrated such patient characteristics to be age >75 (OR 1.71, 95%CI 1.09-2.68, p=0.033), BMI < 30.0 (OR 1.5, 95% CI 1.02-2.20, p=0.044), lowest intraoperative hematocrit between 22-25 (OR 1.77, 95%CI 1.16-2.68, p<0.001), and cardiopulmonary bypass use (OR 4.50, 95%CI 2.25-9.01, p<0.001).

CONCLUSIONS:

Blood conservation can successfully yield reduction in perioperative blood product use, with associated decrease in the risk of postoperative renal failure. A select patient population that may tolerate blood conservation safely was identified and this may guide a targeted blood conservation effort.