Researchers point to risks presented by the lack of oxygen delivered to key organs, which can result in stroke or adverse cardiac events. It has now been suggested that perhaps up to 60% of blood transfusions are not good for patients. Although blood transfusions are commonly given during various surgical procedures, e.g. orthopaedic, concern about the risk in blood transfusions for cardiac surgery patients has been particularly highlighted. In one study, published in November by the journal Circulation, researchers at Bristol University and the Bristol Heart Institute, followed 8,500 cardiac surgery patients for an eight-year period and found that red blood cell transfusions increased the risks of heart attack or stroke three-fold – and, in the month after surgery patients were six times more likely to die than patients who did not receive donated blood.
The risks associated with blood transfusion occurred regardless of haemoglobin levels, age, or level of patient disability at the time of transfusion, the researchers point out. The finding, which implicates the cause being lack of oxygen to key organs, has knocked the widespread belief that red cell transfusion improves oxygen delivery to tissues, and that surgical patients are helped by a ‘top up’ of red cells. In the UK, for example, over 50% of all cardiac surgery patients receive transfusions, yet only about 3% are given due to life-threatening bleeding.
The rest are usually given on the basis of a low haemoglobin level, disregarding whether the patient has physical symptoms to suggest they need blood. Along with danger to patients, hospital costs increase due to adverse events. ‘The study demonstrates the cost implications of our current transfusion practice. This is important, particularly in modern health systems where resources are finite, and should encourage the sort of research that will address the major health issues raised in the study,’ said the study’s lead author Gavin Murphy of Walport Consultant Senior Lecturer in Cardiac Surgery at the University of Bristol.
The researchers aim to undertake a larger study to ascertain whether changing transfusion guidelines could improve patient outcomes. Presently the suggestion is that surgeons should think twice before giving blood transfusions. In March, the New England Journal of Medicine found that patients who received blood that was more than two weeks old were up to 70% more likely to die within a year than patients who received fresher blood. The question of how red cell transfusions may affect immunity or tissue oxygenation needs further study, as does the question of how the safety of donor blood storage could be improved.
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