All heart surgery patients universally require hydration, which is given through a vein in the arm, but practices for treating patients are not universal. There are disagreements about whether crystalloids should be used alone or in combination with albumin. This question has important implications because albumin is an expensive blood product in relatively limited supply, and 20% of its use is by heart surgery patients. The goal of this study is to learn more about how crystalloids and albumin are used during heart surgery, as well as, key patient outcomes.

The goal of this proposed multicentre retrospective cohort study is to characterize perioperative usage patterns of crystalloids and albumin, as well as key patient outcomes, in cardiac surgical patients. This study will also address numerous other knowledge gaps in the area of perioperative blood product management and fluid administration in cardiac surgery and define a collaborative group to support future research in this field.

The primary objective is to obtain granular information on if, when, and how albumin is given perioperatively to cardiac surgical patients. This includes the doses and settings in which albumin is used, the types of crystalloid solutions (balanced or unbalanced) used, and when albumin is used (for example, while on cardio-pulmonary bypass, in the ICU, or on the ward) in perioperative cardiac surgical care across institutions. This important information about the scope of albumin and crystalloid use across the country will inform the design of our future intervention and control arms in the planned definitive trial.

Inclusion Criteria:

• Adult (≥18 years old)
• Cardiac surgery with the use of cardiopulmonary bypass
• Cardiac surgery without the use of cardiopulmonary bypass

Exclusion Criteria

• None

The study will include up to 500 adult (≥18 years old) patients who have undergone major cardiac surgery. All adult (≥18 years old) patients who have undergone cardiac surgery (with or without the use of cardio-pulmonary bypass) will be eligible. There are no specific exclusion criteria.