(P-PB-19) Implementation of a New Restrictive Red Blood Cell Transfusion Threshold for Hematology and Oncology Patients

AABB recently published the 2023 International Guidelines for Red Blood Cell (RBC) Transfusion, providing a conditional recommendation to use a restrictive 7.0g/dL hemoglobin (Hgb) threshold for patients with hematologic-oncologic disorders. Historically, transfusion practice at this institution was to transfuse patients with hematocrit (Hct) < 26%. This project aimed to standardize the use of Hgb values for transfusion decisions and implement a Hgb < 7.0g/dL for RBC transfusion.

Study

Design/Methods:

The project was developed and implemented by members of the Patient Blood Management Committee. A systematic literature review identified 8 clinical trials evaluating Hgb thresholds for hematologic-oncologic patients and a summary was presented to hematology faculty. A consensus was reached that a more restrictive 7.0g/dL Hgb threshold could be safely implemented in this population. Patients with sickle cell disease, undergoing stem cell transplant, and outpatients were excluded. Informational handouts and oral presentations were provided to impacted clinical staff in a multidisciplinary educational campaign. A new best practice alert was enacted in the electronic health record. Outcomes measures included pretransfusion Hgb/Hct values, length of stay, RBC and platelet units transfused, fever days, days Hgb dropped to lower values (6.5, 6.0, 5.0g/dL), and transfusion reactions; at 31 months pre and 6 months post implementation. Metrics were normalized to patient-days (PTD) per time frame to adjust for varying patient volumes.

Results/Findings:

The alert fired on 4.7% of RBC orders where Hgb was >7.0g/dL, and the order was canceled in 18.6% of cases. Hgb and Hct prior to transfusion showed a shift toward the threshold (Mean Hct pre=23.4, post=20.4, P=< 0.001; Hgb pre=7.93, post=6.89, P=< 0.001) (Figure 1). RBC transfusions/PTD decreased by 30% (pre=0.166, post=0.117, P < 0.001). There was no significant difference seen in patient outcome metrics for hospital length of stay (pre=8.1, post=9.37, P=0.17), platelet transfusion/PTD (pre=0.111, post=0.114, P=0.99), transfusion reactions/PTD to RBC (pre=0.011, post=0.011, P=0.99), fever days/PTD (pre=0.359, post=0.352, P=0.74), positive blood cultures/PTD (pre=0.008, post=0.011, P=0.39), or percent readmissions within 48 hours (pre=0.00002, post=0.0013, P=0.40). Days Hgb dropped to 6.5g/dL /PTD increased (pre=0.016, post=0.031, P=0.003), but no significant change was seen at Hgb 6.0 or 5.0g/dL. Approximately 259 transfusions were avoided in the first 6 months after implementation.

Conclusions:

A 7.0g/dL Hgb threshold for hematologic-oncologic patients was successfully implemented. A small fraction of patients had Hgb values that dropped below levels where safety has not been investigated. While the number of transfusions decreased, no changes were notable in other outcomes evaluated. Additional studies will help determine the safety of hemoglobin levels < 6.5g/dL.