Blood Products Should Be Used Conservatively in Heart-Surgery Patients, Trial Shows
The study, presented by medical student Robert Riddell (Dalhousie University, Halifax, NS), was conducted at the Maritime Heart Center in Halifax, NS in 3842 consecutive patients undergoing all types of cardiac surgery. The patients were sorted into four groups: the first received no blood product transfusions; the second received blood products during their surgery; the third group received blood products within the first 48 hours; and the fourth received blood products 48 hours or later after surgery.
After adjustment for baseline differences including preoperative renal failure, gender, left ventricular ejection fraction, age, and procedure type, a logistic regression found that the administration of blood products dramatically increased morbidity and mortality of patients compared with those who received no blood products. Furthermore, the study suggests patients are worse off the later they receive the blood transfusion.
Risk ratios (95% CI) compared with patients receiving no blood products by timing of administration| Outcome | Intraoperative | Within 48 h postop | After 48 h postop |
| In-hospital mortality | 7.71 (4.44-13.38) | 7.09 (3.95-12.72) | 10.37 (5.21-20.63) |
| Acute renal failure | 3.98 (2.77-5.74) | 4.12 (2.82-6.03) | 10.78 (7.03-16.52) |
| Sepsis/DSWI | 3.74 (1.85-7.57) | 4.11 (1.99-8.48) | 11.84 (5.56-25.23) |
Maritime Heart Center’s director of research in the division of cardiac surgery, Dr Jean-Francois Légaré (Dalhousie Medical School), explained the motivation for the study to heartwire. “If you’re bleeding to death, you need blood, but once you are stable and anemic—it is less clear,” he explained.
Previous research, reported by heartwire, has shown a trend toward harm from blood transfusions in some surgery patients, but the Halifax study was the first to focus exclusively on stable patients who are not at risk of bleeding to death, Légaré said.
Légaré said that although there are guidelines for administration of blood products in Canada, the amount of blood products given stable surgery patients varies greatly from center to center.
“The perception is that someone who is anemic should be given blood, [but the study shows] that we need to be more aggressive in not giving blood” and reinforces the need for blood conservation strategies and the development of more stringent criteria for the administration of blood products to stable surgery patients.
He also suggests that centers should reevaluate their processes for taking blood from patients for diagnostic tests so there will be less need for replacement blood products. For example, a patient in an ICU will often give up to two units of blood per week for various diagnostics. Légaré suggested centers consider adopting new methods and technologies that require smaller blood samples.
