To the Editor:—
We read with interest the recent Special Article entitled “Gerard W. Ostheimer ‘What’s New in Obstetric Anesthesia’ Lecture.”1As proponents of blood conservation, we were particularly interested in the obstetric hemorrhage section of the article. We found it curious that the author stressed the use of interventional radiology, darbepoetin, Sengstaken-Blakemore esophageal balloon catheters, and recombinant factor VIIa in the management of obstetric hemorrhage. Advocacy for these techniques is supported by single case reports, whereas therapies such as cell salvage or intravenous iron are given little attention.
In the special article, it is reported that 2–3 units of blood can be obtained from cell salvage. In fact, much more can be returned to the patient when the users of the equipment have a sound understanding of the parameters that influence cell salvage efficiency. The safety of cell salvage has been questioned, but there are approximately 390 reports in the literature of cell salvage being used safely.2–4All known components of amniotic fluid can be removed from shed blood to a concentration equivalent to what is circulating in the maternal circulation.5A recent editorial in the British Journal of Obstetrics and Gynaecology argued that the time has come to accept cell salvage as a safe modality.6It seems unreasonable to argue for the use of recombinant factor VIIa, a drug with a cost of approximately $4,000/dose, based on a single case report and spurn a technology such as cell salvage, where the overwhelming body of evidence suggests safety.
The author argues for the use of darbepoetin, a long-acting form of erythropoietin, but no data exists to support its use in this setting. It is even questionable whether erythropoietin has a role in obstetrics because endogenous erythropoietin concentrations are increased to 2–4 times normal. In general, obstetric patients are iron deficient. Endogenous erythropoietin concentrations seem to be correlated with the degree of iron deficiency.7We would argue that the appropriate method of increasing erythrocyte mass in obstetric patients is through the use of intravenous iron therapy alone. In the hematology practice of one of the authors of this letter (P. F.), pregnant Jehovah’s Witnesses have been treated with intravenous iron or intravenous iron combined with erythropoietin. Intravenous iron resulted in a mean increase in hemoglobin of 2.36 g/dl (n = 32), whereas the combination of intravenous iron and exogenous erythropoietin resulted in a mean increase of 2.23 g/dl (n = 18). In the Special Article, the implication is made that erythropoietin may be a causative agent for preeclampsia. Based on this caution, it seems that the most appropriate method of increasing erythrocyte mass is through iron supplementation.
We also question the role of interventional radiology. Intraarterial balloon catheters require a catheterization laboratory and an interventional radiologist. A significant percentage of obstetric hemorrhage occurs unexpectedly and at hours when interventional radiologists are typically not available. Many reports of this treatment modality record significant transfusion needs for patients with these catheters, raising the question as to how useful the catheters are.
Perhaps cell salvage and supplemental iron do not have the glamour of interventional radiology, darbepoetin, Sengstaken-Blakemore esophageal balloon catheters, and recombinant factor VIIa, but they seem to be far more effective and less costly than these newer techniques. So, we suggest that “What’s old in obstetric anesthesia?” should be the answer when addressing obstetric hemorrhage.
*University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania. watejh@upmc.edu
