Perioperative blood transfusions

The debate regarding the impact of blood transfusions on outcomes spans decades, but many questions, especially concerning any associated cardiovascular risks, remain unanswered. Despite several high profile studies suggesting that a restrictive transfusion strategy might be superior to more liberal approaches,1 2 3 firm consensus is far from established. For example, the most recent meta-analysis published on this topic, with 31 trials and 9813 patients, found no difference in overall morbidity and mortality between liberal and restrictive strategies.4 Importantly, the statistical model in that study was unable to reach the “required information size” for the analysis of mortality and myocardial infarction, a consistent limitation of rare event research, even when data are pooled from a relatively large number of clinical trials.

It is within this context that a linked article by Whitlock and colleagues shows the value of large population based datasets.5 Analyzing data from over 1.5 million patients admitted for surgery to 346 hospitals in the United States, the authors found that receipt of as little as one unit of blood was associated with a 2.33-fold …