Do Institution-Level Blood Utilization and Blood Management Initiatives Meaningfully Impact Transfusion Practices in Cardiac Surgery?

In the current issue of Anesthesia & Analgesia, Camaj et al¹ present findings from a study examining “organizational contributors” to center-level variation in low volume (1–2 units) intraoperative red blood cell (RBC) transfusion rates in the setting of isolated, nonemergent coronary artery bypass grafting (CABG) procedures. Cardiac surgery programs participating in the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative were surveyed regarding organizational blood management practices at their respective institutions. For the purpose of the study, programs were stratified into 2 groups (ie, low versus high transfusion rate centers) based on each center’s 1 to 2 units intraoperative RBC transfusion rate. Survey results did not identify any meaningful differences in organizational blood management practices between low- and high-rate intraoperative transfusion centers, leading the authors to suggest that other determinants, including organizational culture and/or provider-level transfusion practices, may help to explain the variation in transfusion rates.

The transfusion of even 1 unit of RBCs is a costly procedure associated with an increased risk of postoperative morbidity and mortality in the setting of cardiac surgery.^2,3 Additionally, transfusions are associated with a host of well-documented infectious and noninfectious risks, including potentially fatal transfusion reactions, transfusion-related acute lung injury, transfusion-associated circulatory overload, and alloimmunization.⁴ Recognizing these risks, as well as the critical importance of a responsible approach to patient blood management (PBM) for improving patient outcomes, the Society for the Advancement of Blood Management was founded in 2001. According to the Society for the Advancement of Blood Management, the average cost of transfusing just 1 unit of RBCs is $1200, while up to 50% of transfusions are prescribed for no justifiable reason, at a societal cost of $8.4 billion (excluding costs of complications).⁵ Accordingly, without interventions, such as center-level PBM programs, it is likely that demand for blood products will outstrip supply with a continually growing and aging patient population. It is also worth noting that cardiac surgery is among the largest consumers of blood products in medicine, accounting for up to 25% of all RBC transfusions in the United States.^6,7

In light of their study results, Camaj et al¹ acknowledge that there is significant support in the literature for the use and value of PBM programs.⁸ In particular, the authors highlight our experience at the University of Alabama at Birmingham (UAB) Hospital reported by Oliver et al.⁹ Recognizing a steady increase in RBC demand, exceeding desired targets (best practice benchmarks) provided by a blood management consultant, which coincided with severe RBC shortages, a multidisciplinary effort was started at UAB in 2007 to close the gap between blood collections and RBC utilization.¹⁰ Of note, 6 of the top 15 Medical Severity-Diagnostic Related Groups for RBC use involved cardiac surgery. Following institution of a restrictive RBC transfusion approach, a 43% reduction in RBC units transfused per patient discharged was observed from 2007 to 2011. Pre-PBM, 19,888 RBC units were transfused (0.96 units per patient discharged), compared with 14,472 post-PBM (0.55 units per discharge). Of further interest was the observation that the largest absolute decrease in RBC transfusion occurred in cardiovascular surgery, with a decrease of 1.5 units per patient (average of 3.3 vs 1.8 units per patient, respectively; P < .0001). This trend has continued at UAB beyond the 2011 data evaluated in the study by Oliver et al,⁹ both across the institution and, specifically, within cardiovascular surgery (DS Deas, MD, unpublished data, 2017). Of particular relevance to this discussion, is a significant decrease in the number of patients receiving RBC transfusions (and number of units per transfused patient) during hospitalizations for CABG procedures (Figure).

Figure.: University of Alabama at Birmingham Hospital data demonstrating a steady decrease in the percentage of patients transfused (A) and number of RBC units/transfused patient (B) for both coronary bypass MS-DRGs 234 (coronary bypass with cardiac catheterization without major comorbidity) and 236 (coronary bypass without cardiac catheterization without major comorbidity) from 2008 to 2015. MS-DRG indicates Medical Severity-Diagnosis Related Groups; RBC, red blood cell.

Among the largest interventions in the UAB experience was the revamping of the existing Blood Utilization Committee and renaming it the “Blood Utilization and Management Committee,” while adding new members representing disciplines that routinely order transfusions, including perfusionists. Such members all expressed a commitment to educating colleagues regarding the importance of PBM. Furthermore, the role of the committee extended beyond the review of blood usage and utilization, to focus on a restrictive transfusion approach while promoting reduction in transfusion-related errors to ensure safe and effective use of blood products throughout the institution, not just in the operating rooms. We agree with Camaj et al¹ that a key consideration to any center-level PBM committee is its membership composition. The authors allude to this point in their discussion, suggesting that additional studies related to this issue are needed, focusing on defining the appropriate membership that maximizes the effectiveness of a PBM program.

Based on their results, Camaj et al¹ suggest organizational culture, as opposed to center-level PBM practices, may better explain variation in transfusion rates. We agree that culture plays an important role in transfusion practice; however, one may ask the question whether hospital culture and organizational practices are not closely related entities. In a study evaluating the contribution of hospital influence on the transfusion practices of individual cardiac surgeons, Jin et al¹¹ reviewed data related to perioperative transfusions in a collaborative of 12 cardiac surgery programs and 13 interventional cardiology programs throughout 5 states. Their findings noted that blood utilization was significantly different among facilities, but that surgeons practicing at the same facility tended to have similar rates and patterns of transfusion. An interesting conclusion from this study was that institutional culture can influence transfusion practices in a number of different ways, such as: the group of providers caring for cardiac surgery patients is typically well-defined and “close knit”; providers tend to develop commonly accepted practices within their group; the group may engage in ongoing quality improvement projects and share data; each individual institution has its own particular methods and procedure for blood resource management, including blood bank and blood supply access; surgeons and other providers within an institution are likely to have similar educational backgrounds and training; and the patient demographic is likely comparable at each institution. In looking at these conclusions, it seems intuitive to suggest that specific aspects of institutional culture provide the necessary framework for the successful organization of its interdisciplinary PBM practices. Nevertheless, these distinctive factors inherent to cardiovascular surgery programs necessitate unique considerations within the broad structure of an institution-wide PBM management program.

Cultural practices may in fact be the most important measure to review when monitoring appropriate transfusions within an institution. Without exposure to benchmarks for transfusions, evidence-based practices, and institutional support from administration, it is more likely that an institution would have liberal transfusion practices.⁹ In the cardiac operating room, initiating changes in the ordering and delivery practices of blood products may also improve efficiency and lead to a marked reduction of wasted products. Transfusion triggers and techniques that are evidence-based, such as the recommendations of the Society of Thoracic Surgeons and Society of Cardiovascular Anesthesiologists Blood Conservation Guidelines, provide validity of the effectiveness of proposed changes.¹² Establishing a multidisciplinary team approach in the operating room is regarded as a best practice to achieve goals such as limiting hemodilution, a major contributing factor during cardiac surgery that will aid in reducing allogeneic blood transfusions. Several strategies, such as reducing the size of the cardiopulmonary bypass circuit, retrograde autologous priming of the circuit, acute normovolemic hemodilution, and the use of intraoperative cell salvage techniques, are just a few of the methods that we utilized and that are supported by the Society of Thoracic Surgeons. In addition, we created protocols for transfusion triggers, mutually agreed upon by anesthesiologists, surgeons, perfusionists, and intensive care specialists, and initiated discussions involving the entire perioperative team during the preoperative briefing. For non-RBC transfusions, perioperative point-of-care testing (venous and arterial blood gases, coagulation studies, thromboelastography) replaced a broad-based, “shotgun” approach to achieving hemostasis.¹³

One can also not ignore the potential for provider-level factors contributing to variability in transfusion practice. Jin et al¹¹ specifically noted that RBC transfusion rates tended to be lower for surgeons with higher volumes. The 2011 Update to The Society of Thoracic Surgeons and Society of Cardiovascular Anesthesiologists Blood Conservation Clinical Practice Guidelines acknowledge that procedures requiring cardiopulmonary bypass increase the need for blood transfusion compared with cardiac procedures performed “off pump.”^12,14 Thus, surgical volume, surgeon experience, and surgical approach (ie, off versus on-pump CABG) are all potential contributors to variations in transfusion practice.

The benefits of low volume transfusions (1–2 units of RBC) for nonacute and life-threatening bleeding in patients undergoing CABG remain to be defined. Utilizing the expertise of a PBM committee to shape transfusion practices in an institution seems to provide the best opportunity to support challenging clinical decisions moving forward, while we await for data from well-designed studies.

DISCLOSURES

Name: Matthew M. Townsley, MD, FASE.

Contribution: This author helped writing up, reviewing, and revising the manuscript.

Name: Joseph G. Timpa, CCP, FPP.

Contribution: This author helped writing up, reviewing, and revising the manuscript.

Name: James E. Davies Jr, MD.

Contribution: This author helped writing up, reviewing, and revising the manuscript.

Name: Marisa B. Marques, MD.

Contribution: This author helped writing up, reviewing, and revising the manuscript.

This manuscript was handled by: Jean-Francois Pittet, MD.