Blood Conservation-A Team Sport

Abstract

Cardiac surgery accounts for between 15% and 20% of all blood product utilization in the United States. A body of literature suggests that patients who are exposed to even small quantities of blood have an increased risk of morbidity and mortality, even after adjusting for pre-operative risk. Despite this body of literature supporting a restrictive blood management strategy, wide variability in transfusion rates exist across institutions. Recent blood management guidelines have shed light on a number of potentially promising blood management strategies, including acute normovolemic hemodilution (ANH) and retrograde autologous priming (RAP). We evaluated the literature concerning ANH and RAP, and the use of both techniques among centers participating in the Perfusion Measures and outcomes (PERForm) registry. We leveraged data concerning ANH and RAP among 10,203 patients undergoing isolated coronary artery bypass grafting (CABG) procedures from 2010 to 2014 at 27 medical centers. Meta-analyses have focused on the topic of ANH, with few studies focusing specifically on cardiac surgery. Two meta-analyses have been conducted to date on RAP, with many reporting higher intra-operative hematocrits and reduced transfusions. The rate of red blood cell transfusions in the setting of CABG surgery is 34.2%, although varied across institutions from 16.8% to 57.6%. Overall use of ANH was 11.6%, although the utilization varied from .0% to 75.7% across institutions. RAP use was 71.4%, although varied from .0% to 99.0% across institutions. A number of blood conservation strategies have been proposed, with varying levels of evidence from meta-analyses. This uncertainty has likely contributed to center-level differences in the utilization of these practices as evidenced by our multi-institutional database. Perfusion databases, including the PERForm registry, serve as a vehicle for perfusionist's to track their practice, and contribute to multidisciplinary team efforts aimed at assessing and improving the value of cardiac surgical care.

Keywords: blood conservation; blood transfusion; cardiopulmonary bypass; surgery.

Figure 1.

Center-level variation in total perioperative red blood cell units transfused. Each bar represents the percent use of 1 (light gray), 2 (medium gray), or ≥3 (black) units transfused at a given institution among isolated CABG procedures between 2010 and 2014. The x axis represents unique institutions contributing cases.

Figure 2.

Center-level variation in the use of ANH. Each bar represents the percent of ANH use at a given institution among isolated CABG procedures between 2010 and 2014. The x axis represents unique institutions contributing cases.

Figure 3.

Center-level Variation in the use of RAP. Each bar represents the percent of RAP use at a given institution among isolated CABG procedures between 2010 and 2014. The x axis represents unique institutions contributing cases.