Exploring the Potential Role of Hemoglobin-Based O2 Carriers in a Pandemic Simulation of the Blood Supply Chain

Introduction: The recent outbreak of coronavirus disease 2019 (COVID-19) has a significant effect on regional and national blood supply chains. Due to decreased donor availability, inadequate access to COVID-19 tests, and closure of many blood donation centers, the total number of available blood units in circulation is unable to meet clinical demand. Hemoglobin-based O₂ carriers (HBOCs) are a potential red blood cell (RBC) substitute that may be able to fill the need for RBCs during pandemics or other events that result in blood shortages. Stockpiling HBOCs for such an event is relatively easy given their long shelf life ( > 6 years ) at room temperature ( 25 °C ). Although the current generation of HBOCs has similar performance compared to stored packed red blood cells (pRBCs), there may be issues related to the decreased half-life of HBOCs ( 1-2 days ) compared to pRBCs ( 50 – 100 days). In light of this, the current study uses a simulation of an interregional blood supply chain in a pandemic scenario to assess what role HBOCs may have in the national blood supply.

Methods: The current study uses an interregional stock-and flow simulation of the national blood supply chain in the United States. The simulation tracks the quantity and blood type in blood banks and hospitals in 4 regions of the United States as defined by America’s Blood Centers (ABC). Blood units are collected and transferred from blood banks to hospitals within their respective region. A pandemic simulation was performed by reducing the rate of blood donation within each region. Varying reduction and time for recovery were used as metrics to account for variability in the incubation period and duration of the given pathogen. HBOCs were implemented into the model as an RBC substitute that would only be used if no compatible pRBC unit is available to the patient. A half-life based algorithm was used to determine what percentage of patients would need an additional supplement of HBOC due to its relatively low half-life.

Results and Conclusion: With this model, we were able to quantify how HBOCs may help reduce strain on the blood banking system during a pandemic scenario. In these scenarios, HBOCs were able to attenuate the rate of pRBC deficits. We were also able to quantify how many units of HBOCs may be needed in future pandemic scenarios. This tool may be useful in planning and preparing for future pandemic scenarios after HBOCs obtain clinical approval.