血液疾患と輸血ジャーナル

概要

Does Preoperative Anemia Deteriorate Patients’ Postoperative Outcome or about the Difficulty of Comprehension

Sirilak Suksompong and Benno von Bormann

The effect of red cell transfusion is frequently overrated, probably because decision makers are not always familiar with oxygen physiology. Even halving the hemoglobin does not lead to a critical shortage of oxygen supply for the tissues, as long as circulation is normal. However, preoperative anemia is proven to be correlated to deterioration of surgical patients’ outcome. The reason for this is debatable, and most scientists estimate anemia as a surrogate parameter for patients’ general condition and co-morbidity. There are several studies regarding anemia and red cell transfusion within the huge database from the American College of Surgeons National Surgical Quality Improvement Program, these studies often apply highly sophisticated statistical approaches. Some studies found that preoperative anemia is independently associated with an increased risk of postoperative mortality and morbidity, but this is not confirmed by other researchers, despite using the identical data source. Therefore, up to now there is no conclusive evidence that preoperative anemia exclusively influences the outcome of surgical patients. The average reader of scientific literature cannot always cope with the complicated statistical methods employed, thus being unable to comprehend the message of a publication. To make it even worse, highly ranked statisticians estimate up to 90% of medical studies to be biased and claim that unreliable data are the rule in medical literature. The more sophisticated research methods are applied, the more comprehensibility is needed for publishing results, following the suggestion of Leonardo da Vinci, “Simplicity is the ultimate sophistication”.