Red Blood Cell Transfusions

IRON-RECOVERY is a prospective, multicenter, observational cohort study designed to determine the prevalence of iron deficiency at intensive care unit (ICU) discharge and to evaluate its association with post-ICU clinical recovery. Anemia is highly prevalent in critically ill patients and frequently persists after ICU discharge. Although inflammation-induced iron dysregulation is considered one of the main mechanisms underlying persistent anemia, iron deficiency remains largely under-recognized in this population because conventional biomarkers, particularly ferritin, are influenced by the inflammatory response. Transferrin saturation (TSAT) has emerged as a more reliable marker of iron availability and may better identify patients with iron-restricted erythropoiesis. Adult patients admitted to participating ICUs for at least 72 hours will undergo assessment of iron status at ICU discharge using routine laboratory tests, including hemoglobin, serum iron, transferrin, ferritin, TSAT, and inflammatory markers. When available, admission iron parameters will also be collected to evaluate changes during the ICU stay. No study-specific therapeutic intervention will be mandated, and all treatment decisions, including intravenous iron administration, will remain at the discretion of the treating physicians. The primary objective is to determine the prevalence of iron deficiency (defined as TSAT \<20%) at ICU discharge. Secondary objectives include evaluating the association between iron deficiency and post-ICU red blood cell transfusion requirements, hemoglobin recovery, functional status assessed by EQ-5D, hospital readmission, mortality, and days alive and out of hospital. Exploratory analyses will assess the association between intravenous iron therapy and clinical outcomes after adjustment for confounding factors. Also, risk factors for ICU-acquired iron deficiency will be investigated. The findings of this study are expected to provide the first prospective multicenter estimate of iron deficiency at ICU discharge and to inform the design of future interventional trials evaluating iron replacement as part of post-ICU patient blood management strategies.

Red blood cell (RBC) transfusions are selected based upon matching donor and recipient blood group: donor and recipient sex are not considered when selecting blood for transfusion. Hence, transfused patients can currently receive sex-matched and/or unmatched RBCs when transfusions are given. Sex-matched stem cell transplants, and some solid organ transplants, have shown that sex-matching donor to recipient improves patient outcomes. Recent exploratory studies have also suggested that patient outcomes could be improved by sex-matching for RBC transfusion. There is emerging evidence of underlying biologic mechanism(s) to support these observations. This study is designed as a randomized controlled trial and will explore the impact on patients who receive RBC transfusions from donors of the same sex ("sex-matched") compared with donors of the opposite sex ("sex-mismatched"). The trial will study adult patients admitted to the Intensive Care Unit who require an RBC transfusion. Patients will be assigned (through a process called randomization) to receive sex-matched RBCs or sex-mismatched RBCs to determine if there is a difference in mortality between those receiving matched versus mismatched RBCs. The results of this trial could have direct implications on resources, blood inventory, and RBC transfusion ordering practices.