Grant: Project Grant

Blood transfusion is the one of the most frequently prescribed therapies in hospitals that is essential for surgery, cancer treatment, and traumatic injuries. Blood is especially important for open heart surgery, with up to 6 in 10 people having heart surgery getting red-blood-cell transfusion, using 10-20% of Canada's blood supply. However, despite its critical importance, the supply of donated blood is unstable, and strategies to minimize the need for blood transfusion during heart surgery are urgently needed. One reason that heart surgery patients often require transfusion is that to be safely connected to the heart lung machine, they receive a large volume of saline fluid that fills the tubes of the heart lung machine. This fluid dilutes the patient's hemoglobin level such that, even if bleeding during surgery is minimal, that patient may still need a blood transfusion because their hemoglobin level is critically low. Small studies in select patients have shown that a simple technique called retrograde autologous priming (RAP) can be used to fill the tubes of the heart lung machine with the patient's own blood, rather than fluid, and may reduce blood transfusion. Our goal is to learn if hospitals that use RAP as their default approach use fewer units of blood in the first 72 hours after surgery than hospitals that use fluid. We will study 20 Canadian hospitals. Each hospital will follow one policy for four weeks, then switch to the other policy, repeating this over the course of 1-year. All patients on the heart-lung machine during these periods get their usual safe care; we only compare the two normal ways of filling the machine and track standard outcomes from hospital records. If RAP helps, hospitals can easily adopt it because it uses staff and equipment already in place. Even a modest improvement could save thousands of units of blood and millions of dollars each year, lowering risks for patients, and making Canada's blood supply more stable.