M. Macke, J.-C. Müller, R. M. R. Olivier, A. U. Steinbicker, U. Karst
University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstr. 28/30, 48149 Münster, Germany
Iron deficiency anemia is one of the most common medical disorders worldwide, and affected individuals who undergo major surgery have an increased risk of postoperative morbidity and mortality. Therefore, supplementation of intravenous iron (IVI) preparations up to one day before surgical intervention is strongly recommended for these patients. Frequently administered iron supplements, such as ferric carboxymaltose (FCM), consist of a nanoparticulate Fe(III)-oxyhydroxide core surrounded by a carbohydrate shell and allow controlled delivery of iron. If high blood loss is expected, additional perioperative cell salvage is employed: blood from the surgical field is collected, washed, and the patient’s own red blood cells are re-transfused. However, there is no data on the impact of this practice on short-term IVI supplementation.
In order to assess a potential wash-out effect of IVI by perioperative cell salvage, sensitive and quantitative techniques of speciation analysis are required. In this work, we present the utilization of complementary approaches to determine FCM in the highly complex matrix of serum samples. A method based on size-exclusion chromatography (SEC) was developed, enabling a fast on-line separation of FCM from the Fe-containing blood protein fraction of holo-transferrin in less than 10 min. In combination with quadrupole-based inductively coupled plasma-mass spectrometry (ICP-MS), quantification with species-specific detection limits in the low ng/mL range was achieved. Furthermore, electrospray ionization-mass spectrometry was employed to provide detailed structural information about the compounds of interest.
The presented SEC-ICP-MS method has proven to be a valuable tool for the rapid monitoring of IVI in serum samples. It was finally applied in the context of a medical trial that included a total of 23 patients who underwent elective cardiac surgery with perioperative cell salvage. Quantitative results for blood samples that were obtained before, during, and after surgical procedures indicate a wash-out effect of previously administered FCM.