An In Vitro Pilot Study Comparing the Novel HemoClear Gravity-Driven Microfiltration Cell Salvage System with the Conventional Centrifugal XTRA™ Autotransfusion Device

HemoClear: A Practical and Cost-Effective Alternative to Conventional Convalescent Plasma Retrieval Methods

Convalescent plasma has increasingly been used to treat various viral infections and confer post-exposure prophylactic protection during the last decade and has demonstrated favorable clinical outcomes in patients infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) during the recent COVID-19 pandemic. The pandemic has highlighted the need for cost-effective, accessible, and easy-to-use alternatives to conventional blood plasmapheresis techniques, allowing hospitals to become more self-sufficient in harvesting and transfusing donor plasma into recipients in a single setting. To this end, the use of a membrane-based bedside plasmapheresis device (HemoClear) was evaluated in an open-label, non-randomized prospective trial in Suriname in 2021, demonstrating its practicality and efficacy in a low-to middle-income country. This paper will review the use of this method and its potential to expedite the process of obtaining convalescent plasma, especially during pandemics and in resource-constrained settings.

Comparison of Washing Efficiency and Recovery of Blood Cells Between Centrifugation, Coarse Filtration and Microfiltration Techniques to Prepare Autologous Blood for Transfusion

Purpose

Cell salvage is the process by which blood lost in surgery is collected and washed or filtered to produce autologous blood for re-transfusion to the patient. Cell salvage aims to reduce the need for donor blood. Centrifugal cell salvage washing technique is a preferred medical treatment in order to retain lost red blood cells (RBCs) without contaminants. Although this technology very efficiently collects and washes shed blood, it is costly and often impractical or unavailable, especially in middle- or low-income countries. This study assessed two innovative filter devices as an alternative to centrifugal cell salvage technology: a coarse collection filter device (Hemafuse) and a microfiltration device (HemoClear). In contrast to centrifugal technology, both filter devices do not require electricity, nor costly equipment and extensive training. We compared the effectiveness of these filtration technologies to remove plasma constituents and recover and concentrate the cellular components with centrifugal technology (autoLog^® device).

Methods

Whole blood was processed with each technology according to the device manufacturer’s instructions. Before and after processing, the blood products were analyzed for supernatant solutes and cellular composition.

Results

The centrifugal technology confirmed its efficacy to remove potentially harmful solutes and capture red blood cells. The microfiltration technology (HemoClear) reached comparable levels of removal of solutes, with a potential advantage over centrifugal technology in the ability to also recover platelets. The coarse filtration technology (Hemafuse) had no washing capacity but, like the microfiltration technology, has the advantage of recovering platelets.

Conclusion

Innovative filtration devices represent an alternative to centrifugal technology in the preparation of autologous blood for reinfusion. The HemoClear technology for the first time enables the recovery of washed platelets and red blood cells. Clinical trials will have to be performed to investigate the clinical value of this new autologous blood product.

Cell Salvage in Oncological Surgery, Peripartum Haemorrhage and Trauma

Oncological surgery, obstetric haemorrhage and severe trauma are the most challenging conditions for establishing clinical recommendations for the use of cell salvage. When the likelihood of allogeneic transfusion is high, the intraoperative use of this blood-saving technique would be justified, but specific patient selection criteria are needed. The main concerns in the case of oncological surgery are the reinfusion of tumour cells, thereby increasing the risk of metastasis. This threat could be minimized, which may help to rationalize its indication. In severe peripartum haemorrhage, cell salvage has not proven cost-effective, damage control techniques have been developed, and, given the risk of fetomaternal alloimmunization and amniotic fluid embolism, it is increasingly out of use. In trauma, bleeding may originate from multiple sites, coagulopathy may develop, and it should be evaluated whether re-transfusion of autologous blood collected from uncontaminated organ cavities would be feasible. General safety measures include washing recovered blood and its passage through leukocyte depletion filters. To date, no well-defined indications for cell salvage have been established for these pathologies, but with accurate case selection and selective implementation, it could become safe and effective. Randomized clinical trials are urgently needed.