What can clinicians conclude from this study?
First, the blood savings achieved in this context are modest and of marginal importance (both for patients and for the blood bank) in light of the substantial amounts of HBOC-201 required. One should remember that only anemic patients were enrolled: the blood sparing effect for the entire population would, consequently, be even smaller.
Second, blood savings were achieved at the expense of significant side effects (increased blood pressure, decreased cardiac index and jaundice), as in the study by Lamy et al.
Third, hemoglobin concentrations were similar in all patients at day 6 after surgery. Although a hematinic effect of HBOC-201 is invoked, no data are presented to support this hypothesis. One could also argue that restoration of a normal fluid balance and elimination of the hemodilution observed commonly after cardiopulmonary bypass may be responsible for the rise in hemoglobin concentration. Tolerance of a low transfusion threshold might have resulted in similar blood savings.
HBOC solutions are an interesting concept but the products available at this time present several limitations. Their effect is short-lived because they have a short plasma half-life and are rapidly oxidized to methemoglobin. In addition, their use is associated with clinically significant adverse events while the benefits demonstrated in controlled trials remain modest. Finally, the cost of HBOC-201 remains unknown and may further limit the use of this alternative to transfusions.
– J.-F. Hardy.