An evidence-based review of the practice of cardiopulmonary bypass in adults: A focus on neurologic injury, glycemic control, hemodilution, and the inflammatory response

Abstract

Supplemental material is available online. Cardiopulmonary bypass (CPB) can be used during cardiac surgery to oxygenate and subsequently recirculate blood that has been diverted from the heart and lungs. The practice of CPB has changed-and continues to change-dramatically since its advent in the 1950s. Although structured reviews of the evidence supporting the practice of cardiac surgery have been in the literature for more than a decade and continue to be refined in the wake of new and emerging evidence, E1,E2 additional targeted reviews, focusing on issues such as minimizing the effect of the inflammatory response or minimizing neurologic injury, are warranted. E3-E5 Previous attempts, by Edwards and colleagues E6 and Bartels and associates, E7 at synthesizing the evidence base to support the principles of CPB have selectively reviewed the cardiac surgery literature or focused on unique patient populations. Additionally, the development of these reviews has not involved all members of the clinical team, most notably the individuals tasked with operating the CPB circuit. This gap in knowledge is in stark contrast with the shared goal of the cardiac team, namely to improve the conduct of CPB to reduce the patient's risk of adverse outcomes caused by cardiac surgery.Despite a preponderance of evidence supporting key principles of managing safe and effective CPB practice, wide variation in the use of technology and techniques for conducting CPB persists regionally and nationally. E8,E9 Variations in practice have previously been shown to be associated with increased costs, lengths of stay, neurologic injury, and mortality. 1-3,E5,E10,E11 This variation might be attributed to clinical uncertainty or institutional or local practice standards. To reduce this unwanted practice variation, we must provide our clinical colleagues with critically evaluated and evidence-based review for conducting CPB.What follows is an evidence-based review for conducting safe, patient-centered, and effective CPB practice. The authors have graded the level of evidence and classified the findings listed below by using the criteria promulgated by the American Heart Association and the American College of Cardiology Task Force on Practice Guidelines (Table 1). The development of these findings evolved from a structured MEDLINE search coupled with critical review of the peer-review literature and debates stemming from presentations at regional and national conferences, including the

The Cardiotomy Trial

“…Effective steps were taken to ensure blinding of the patients and all surgical and medical team members to avoid bias in outcomes, and transfusion protocol compliance was excellent. A recent evidence-based review of CPB practice 30 has concluded that the direct reinfusion of unprocessed cardiotomy blood should be avoided (Class I recommendation, Level B level of evidence) 31 and that blood cell processing and secondary filtration can be considered to decrease the deleterious effects of reinfused shed blood (Class IIb, Level B). Our results do not support these recommendations.…”

Continuous-Flow Cell Saver Reduces Cognitive Decline in Elderly Patients After Coronary Bypass Surgery

“…12 A recent evidence-based review assigned a class IIb, level B evidence for blood cell processing and secondary filtration in decreasing the deleterious effects of reinfused shed blood. 13 More studies are required to build up level I clinical evidence.…”

Advantages to Miniaturized Cardiopulmonary Bypass for Adult Cardiac Surgery

“…In a large evidence-based review of the practice of CPB in adults [31], the authors recognized the effective attenuation of the systemic inflammatory response by reduction of the circuit surface area and use of biocompatible surface-modified circuits with miniaturized CPB and gave a Class IIA (Evidence Level B) recommendation. As patients become more informed about avoiding blood transfusions, the imperative to provide improved perfusion strategies will continue to grow.…”