Postoperative Replacement of Intraoperative Iron Losses

In the last few years, state of the art Patient Blood Management (PBM programs have been gaining worldwide attention. This may be attributed to the significant improvements in patient outcomes that follow adequate preoperative preparation and intraoperative optimization of the circulating red cell mass.

The first pillar of PBM (pre-, intra-, and postoperative optimization of red cell mass by means other than red cell transfusions including intravenous iron and erythropoietin stimulating agents) can meet significant barriers and might be difficult to implement. In daily clinical practice, timely identification and treatment of preoperative anemia is difficult to organize due to structural and behavioral constraints. Therefore, today, there are still a striking number of patients who are admitted for surgery without adequate preoperative treatment of anemia regardless of its causes. Notably, even for this patient population, it has been demonstrated by experimental and larger observational data that postoperative application of intravenous iron could help to reduce perioperative transfusions by restoring red cell mass. The complete potential of perioperative intravenous iron therapy has yet to identified, including improvements such as early mobility and other improved outcomes. Furthermore, a substantial number of patients are not included in preoperative red cell mass optimization, since the preoperative hemoglobin concentration is either high enough in terms of the thresholds of the World Health Organization (♂ 13 g/dl and ♀ 12 g/dl), or borderline (mild) anemia is diagnosed and no treatment is offered. These patients may be prone to substantial intraoperative blood losses, and as a consequence might suffer from postoperative iron restricted anemia. In fact, there are a remarkable number of patients that have adequate hemoglobin concentrations preoperatively, but ultimately develop anemia with iron deficiency postoperatively due to significant intraoperative bleeding. Data from ICU patients' with postoperative iron deficiency has significant impact on outcome including postoperative fatigue, and consequently a prolonged healing process.

Although this problem is common, current PBM strategies are in need of validation of one of the PBM guidelines: postoperative replacement of blood loss with resultant iron losses in patients without preoperative anemia thus avoiding exposure to allogeneic transfusions in this population. The untested hypothesis is that this approach could improve postoperative outcomes including mobilization. Based on a recent publication one might surmise that it is not (only) postoperative anemia, but rather untreated iron deficiency, that is responsible for a delay in postoperative mobilization and recovery. It is therefore the aim of the proposal presented to describe an additional approach, in which perioperative, surgical blood loss iron losses are replaced immediately following the surgical procedure in patients that did not receive iron preoperatively due to normal or minor reduction in hemoglobin concentrations (red cell mass). This replacement may take place in either the postoperative anesthesia care unit or in the ICU, Although preoperative treatment of iron deficiency anemia is widely considered the most important domain of perioperative iron therapy, the additional post-operative replacement is as useful as preoperative preparation and seems to be more convenient to implement.

Inclusion criteria

• patients undergoing non-emergency

• cardiac surgery - obstetric surgery - intra-abdominal surgery
• preoperative Hb (during the premedication visit):

• ♂: Hb>12.5g/dl
• ♀: Hb>11.5g/dl
• postoperative Hb (immediately after surgical procedure in the recovery room):

• 2 g/dl below preoperative Hb concentration
• age ≥ 18 years
• Admission to intensive care unit or post-anesthesia care unit
• Able to sign consent for the trial

Exclusion criteria

• age < 18 years
• emergency surgery
• perioperative application of iron and/or erythropoietin
• intraoperative transfusion of allogeneic erythrocytes
• known hemochromatosis
• known allergic reaction linked to iron medication