The investigators will test the hypothesis that utilization of a blood and blood component transfusion algorithm guided by the POC Quantra QPlus System in patients undergoing complex cardiac surgery will reduce RBC, plasma, cryoprecipitate, and platelet transfusion during surgery and the first 12 postoperative hours, compared to standard of care (central laboratory transfusion monitoring at the primary anesthesia provider's discretion).

The Investigators propose a randomized control trial to assess patients scheduled for aortic surgery or high-risk cardiac surgery requiring cardiopulmonary bypass.

Patients will be randomized 1:1 to routine care or POC Quantra QPlus System. The total number of blood and blood component transfusions (including RBC, plasma, cryoprecipitate, and platelets) during and after cardiac surgery until 12 hours after ICU arrival will be analyzed between the groups.

Inclusion Criteria:

1. Adults aged 18 years or more
2. Scheduled for aortic surgery or high-risk cardiac surgery requiring cardiopulmonary bypass (high-risk surgery includes reoperative surgery, active endocarditis, expected need for intraoperative circulatory arrest, radiation heart disease, end-stage kidney disease requiring renal replacement therapy, combination surgery including more than one valve or valve plus CABG, low left ventricular ejection fraction [EF<30%] with potential need for mechanical circulatory support with intra-aortic balloon pump, extracorporeal membrane oxygenation [ECMO], pulmonary thromboembolectomy or percutaneous left ventricular assist device (VAD), and planned placement of a durable left VAD with or without placement of RV assist device.

Exclusion Criteria:

1. Preoperative diagnosis of a pre-existing coagulation or bleeding disorder
2. Preoperative abnormal coagulation disorder (platelet count below 100,000/uL and/or aPTT >40 seconds in the absence of heparin therapy. Prolonged aPTT >40 seconds in the acceptable if due to heparin therapy.)
3. Liver disease, defined as a history of cirrhosis, liver enzymes >3x normal range or manifested by elevated PT suggesting abnormal liver synthetic function not explained by other comorbidities
4. Pregnancy or breastfeeding
5. Refusal to accept red blood cells and blood component transfusions.
6. Contraindications to proposed interventions.
7. Unable to understand English as a first language or unable comprehend the study and/or the consent forms.
8. Vulnerable patients including prisoners, human fetuses, and neonates

Patients and outcome assessor will be masked to the group allocation. Clinicians will be unmasked to group allocation.