Lessons Learned From Jehovah’s Witness Patients: Using a Novel Algorithm to Calculate the Preoperative Hemoglobin Target Required to Avoid Transfusions

From the 2022 HVPA National Conference

Ananda Thomas BA (Departments of Anesthesiology and Critical Care Medicine,  Johns Hopkins Medicine, Baltimore, MD), Nicole Guinn M.D, Nicolas Cruz BA, Janet Adegboye M.D, Joyce Hsiao M.D, Brian Lo M.D, Steve Frank M.D


Providing care to patients who decline blood transfusion can be challenging, especially for procedures where patients may lose large amounts of blood. In these types of cases, optimizing preoperative hemoglobin to account for predicted blood loss is essential. We describe a novel algorithm, derived from the allowable blood loss formula, that is based on body mass and expected blood loss. The formula allows for the calculation of the ideal target preoperative hemoglobin.


After IRB approval, we analyzed our bloodless patient database for spinal surgical procedures completed from 2012 – 2022. We identified 26 patients who declined blood transfusions for religious or personal reasons. Pre, intra, and postoperative data were collected by retrospective chart review. Hemoglobin concentrations were assessed at four-time intervals: 1) Prior to anemia treatment, 2) post anemia treatment preoperatively, 3) immediately postoperative, and 4) upon discharge. Hemoglobin data are given as mean ± SD and comparisons were performed using paired t-tests.


The table and the figure show clinical characteristics, and pre-and postoperative data summarized for all patients. Anemia treatment, such as EPO and/or IV iron, was used in approximately 50% of patients. Intraoperatively, just over half of patients received tranexamic acid, and only 3 patients had enough blood loss to allow salvaged blood reinfusion. There was wide range for blood loss (40 – 1000mL), which showed the algorithm’s ability at both the high and low ends of the spectrum. The mean hemoglobin concentration decreased approximately 1.5 g/dL after surgery, and the lowest hemoglobin upon discharge was 6.7 g/dL. There were no in-hospital mortalities.


The algorithm we present was useful in calculating the target preoperative hemoglobin concentration required to safely allow surgery, while avoiding clinically significant postoperative anemia. Using this algorithm along with best practice intraoperative blood management methods allows safe practice and good outcomes for patients who decline allogeneic transfusion. This algorithm will be useful to guide preoperative anemia treatment even for patients who accept transfusions.

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