PURPOSE: Cardiac surgery requiring cardiopulmonary bypass (CPB) is frequently complicated by excessive bleeding because of coagulopathy. Contact of blood with the CPB circuit is a major contributor. While several Health Canada-approved disposable circuits are available for purchase, there is no existing direct comparative data. Our objective was to conduct a quality assurance project to provide clinical data on the bleeding and coagulation effects of six disposable CPB circuits in a cohort of cardiac surgery patients. METHODS: We compared the effects of six different circuits on bleeding and coagulation in 872 consecutive patients who underwent various types of cardiac surgery over 12 months at Toronto General Hospital (Toronto, ON, Canada). Generalized estimating equations accounting for clustering by surgeon were used to assess the impact of each circuit group on the following: 1) at least moderate bleeding as defined by the Universal Definition of Perioperative Bleeding Score after separation from bypass through the first postoperative day
2) total allogeneic blood product transfusion within seven days of surgery
and 3) hemostatic therapy administration within seven days of surgery. Changes in coagulation tests before and after bypass were recorded. RESULTS: We included 872 patients. There were no major differences between the six types of circuit in prebypass compared with postbypass coagulation tests. Nevertheless, when accounting for surgeon, patient, and procedural characteristics, significant differences between circuit types emerged for all primary and secondary outcomes. CONCLUSION: The findings of this quality assurance project suggest that current Health Canada-approved CPB circuits may have differential effects on coagulation and bleeding. This should be further verified in randomized controlled trials.