This retrospective study assessed the relationship between the degree of acute surgical anemia and a composite ischemic outcome (myocardial infarction, non-fatal cardiac arrest and in-hospital mortality) in a population of relatively low-risk patients with and without beta-blockade (defined as beta-blocker administered within 24 h of surgery). The authors report that severe acute surgical anemia, defined as a reduction of hemoglobin concentration by 35% of baseline value was associated with a significant increase in the risk of ischemic outcome and that this relationship is much worse in beta-blocked patients. The results of this study, however, must be interpreted with caution because of its retrospective nature, and the limitations of such studies are well underscored in the accompanying editorial. What this article tells us is that tolerance to acute severe anemia is decreased in patients receiving agents that impair cardiac output response in this situation.

– Philippe Van der Linden