This multi-centre study will provide sound, generalizable data on the effectiveness of a POC-based algorithm to determine to what extent this guideline can reduce blood product transfusions. Investigators will study outcomes in 7000 patients undergoing heart surgery at 10 participating hospitals. The proposed trial addresses several important research and clinical issues and has the potential to markedly improve the transfusion management and surgical care in general of cardiac surgery patients.

The intervention will be a novel POC-based algorithm that has been shown in a pilot study by us to be associated with a substantial reduction in blood product transfusions. The algorithm will employ viscoelastic and aggregometric POC-tests and an objective measure of blood loss. The primary outcome will be avoidance of red blood cell transfusion during hospitalization. The study has a 90% power to detect a 12% increase in avoidance rate. Secondary outcomes will include avoidance of red blood cell use and other blood products (plasma, platelets, and cryoprecipitate), units of blood products transfused, and adverse clinical outcomes related to transfusion (acute kidney injury, infections, and death). Data will also be collected for future health-economics analyses.

Largely due to the limitations of existing evidence, however, such algorithms are rarely used in clinical practice. The proposed trial will provide sound, generalizable data on the effectiveness of a POC-based algorithm to guide their future use. An integrated blood management algorithm that employs POC coagulation tests will reduce blood product transfusions in cardiac surgery, thereby improving clinical outcomes.

Does an integrated blood transfusion algorithm that employs POC coagulation tests applied across a network of hospitals reduce blood transfusions and associated adverse outcomes in cardiac surgery?

Despite major advances in cardiac surgery, coagulopathy continues to carry a heavy burden in cases that require the use of cardiopulmonary bypass (CPB), occurring frequently and resulting in excessive blood loss, blood product transfusions, and adverse clinical outcomes. Current management of coagulopathy is hampered by the inability of conventional laboratory tests to delineate its etiology in a timely manner, thereby precluding timely and targeted transfusion therapy. With the advent of point-of-care (POC) coagulation tests that can rapidly identify the etiology of coagulopathy, it may now be possible to reduce the burden of coagulopathy and thereby reduce transfusions and adverse outcomes. Several single-centre studies (including one by the investigator group) have found that the use of POC-based algorithms in cardiac surgery can markedly reduce blood product transfusions and by that means reduce morbidities and mortality.

Hospital Inclusion:

• Participating hospitals must not currently be using a POC-based blood conservation algorithm; must have an in-hospital RBC transfusion rate of > 35% and platelet or plasma transfusion rates of > 20%; must conduct > 600 cardiac surgeries employing CPB per year; and must have commitments from departments of Anesthesia, Cardiac Surgery, and Laboratory Medicine to support the study and to abide by the algorithm
• Blood transfusion algorithm instituted as standard-of-care at participating hospitals
• All adult (≥ 18 years) patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) will be included in the analysis.

Exclusion Criteria: Hospitals not meeting inclusion.