From the 2022 HVPA National Conference
Janet Adegboye MD (Departments of Anesthesiology and Critical Care Medicine, Johns Hopkins Medicine, Baltimore, MD), Ananda Thomas BA, Nicolas Cruz BA, Ryan Nicholson B.S, Jessica Asiedu B.S, Steve Frank M.D
There are several validated criteria that can be used to trigger a massive transfusion protocol, such as the shock index and the assessment of blood consumption score. Transfusion then continues until a clinician determines that the patient no longer needs additional blood or the patient is beyond the point where further transfusion will be futile. This is a nuanced assessment that may be difficult to make and there are unclear guidelines for when to stop, which may lead to inadvertent overtransfusion. Unfortunately, transfusion is not benign and can cause electrolyte abnormalities, acid/base disorders, hypothermia, coagulopathy, fluid overload, or acute lung injury. Also, blood is a valuable and limited resource, so the decision to transfuse each unit should be made judiciously. Our goal for this study was to assess the massive transfusion practices at our hospital to test the hypothesis that a substantial number of these patients were overtransfused.
In this retrospective cohort study, patients were included if they received at least 10 units of red blood cells during their hospitalization from 2016 to 2022. We excluded oncology patients because many of them had prolonged hospitalizations with multiple transfusions due to chronic bone marrow suppression, rather than a single large transfusion event. We also excluded patients who did not have post-transfusion hemoglobin measurements prior to discharge. Our exposure was the number of red blood cell units transfused, and our outcome was the percentage of patients who were discharged with their hemoglobin above a certain threshold (either 8, 9, 10, 11, or 12 g/dL). We planned to use Chi-square test of independence or Fisher’s exact test to look for an association between our exposure and outcome. We expected that patients who received more transfusions would have higher hemoglobin measurements at discharge.
There were 41,059 hospitalizations where a blood product was transfused. Of these encounters, there were only 3,582 hospitalizations where the patient received at least 10 units of red blood cells. The most red blood cell transfusions received in a single hospitalization was 491 units. After excluding oncology patients and patients who did not have post-transfusion hemoglobin measurements prior to discharge, we had 2,953 hospitalizations remaining available for analysis. In total, 1,922 patients (65%) were discharged with a hemoglobin above 8 g/dL, 1,033 patients (35%) were discharged above 9 g/dL, and 527 patients (18%) were discharged above 10 g/dL. The highest discharge hemoglobin was 18.1 g/dL. Overall, there was no association between the number of units transfused and the percentage of patients discharged with a hemoglobin above 8, 9, 10, 11, or 12 g/dL (p = 0.13, p = 0.33, p = 0.44, p = 0.40, and p = 0.85, respectively).
Of the patients who received at least 10 units of red blood cells during their hospitalization, about 2/3 had a discharge hemoglobin above 8 g/dL, 1/3 above 9 g/dL, and 1/5 above 10 g/dL. Patients were similarly overtransfused, regardless of the number of units received. These findings reveal an opportunity to reduce unnecessary blood usage by recognizing when to stop giving blood to patients receiving massive transfusion.