CARD13: INDUS: Economical Maglev Centrifugal Blood Pump for Developing Countries- Preliminary In-Vitro Hemolysis Testing

Abstract

Purpose of Study: The Centrimag® is widely used for acute extracorporeal circulatory support. However, it is prohibitively expensive for low- and lower-middle-income countries (LMICs). In order to lower the costs associated with the use of Centrimag®, our India-US consortium is developing an economical centrifugal pump (INDUS), to improve accessibility of this lifesaving device. As a first step, a 3D printed magnetically levitated centrifugal pump head was designed and fabricated (Figure 1), that can fit into a standard Centrimag® motor unit. The objective of this study is to compare the hemolysis caused by the INDUS versus the original Centrimag® system in a mock circulatory loop, under realistic hemodynamic conditions. Methods: The prototype INDUS pump head was inserted into a simple mock-loop consisting of a blood reservoir, inlet and outlet tubing connections and the pump (Figure 2). A 3D printed clamp was used to control the resistance and develop pressure head. Pressure sensors were used to monitor pressure to a laptop using the DataQ system and non-contact Transonic flow probe provided a measure of the flow rate. The hemolysis tests were conducted as per the ASTM F1841-97 Standards using 400±20 mL of fresh, citrated, veni-puncture bovine blood at 30-35% haematocrit. The samples were collected at 0 Hr (baseline), 30 min., 1 Hr, 2 Hr, 3 Hr, and 4 Hr. The flow rate was maintained at 5±0.25 LPM and pressure at 110±15 mmHg. The samples were centrifuged, and the plasma was measured for plasma free hemoglobin, using a Multimode Reader. The normalized index of hemolysis (NIH) was calculated for both the pumps. Results: The NIH values for the original Centrimag® and the 3D printed INDUS were 0.00118 and 0.00166 respectively (Figure 3). Conclusion: The INDUS pump does not cause excessive hemolysis compared to the original Centrimag® pump. These encouraging in-vitro results encourages us to proceed with developing an injection moulded version and to launch further basic biocompatibility testing toward the goal of providing an inexpensive mechanical blood pump that can be accessible to patients in India and other LMICs.Figure 1. 3D Printed prototype of INDUS Pump (IAAHP: Indo-American Artificial Heart Program).Figure 2. Mock loop with Indus pump circulating bovine blood for hemolysis test.Figure 3. NIH comparison for Indus and Centrimag® pumps