Blood transfusions increase circulating plasma free hemoglobin levels and plasma nitric oxide consumption: a prospective observational pilot study.

Vermeulen Windsant IC, Wit de NC, Sertorio JT, et al.
Crit Care 2012;16:R95.
NATA Rating :
Review by : M. Piagnerelli
NATA Review

This pilot study in 30 hematology patients showed an increase in free hemoglobin concentrations during the first day after transfusion of 2 units of red blood cells (RBCs). This was accompagnied with a very transitory (15 min) increase in NO consumption and no modifications in haptoglobin concentrations, except in very low concentrations before transfusion. For the authors, these results may help explain the potential pathophysiological mechanism underlying the deleterious effects of RBC transfusions. Regrettably, it is difficult to extrapolate the results to critically ill patients. Indeed, patients with inflammation (post surgery, sepsis, renal or hepatic failure) were excluded. Other potential mediators for side effects of transfusion, like cytokines, free iron or reactive oxygen species were not measured in this study. Moreover, these transient modifications were observed only after 2 units of RBC.

– Michael Piagnerelli