Study of haemolytic properties of a disk-type pump

Background. A shortage of donor organs is one of the urgent problems of transplantology. Despite the current level of technology, there are a number of difficult barriers to overcome. Because of the high demand for assisted circulatory devices, the work caused by the creation of the most physiological and biocompatible model of the apparatus, exceptional relevance is provided. Aim. To evaluate the haemolytic properties of the auxiliary circulatory apparatus based on a disk-type pump. Methods. A hydrodynamic bench was created to conduct haemolysis tests of a disk-type pump. The bench consisted of a tank, a heat exchanger, hydrodynamic resistance, connecting tubes, a blood sampling port, a pressure and flow measurement system, and a test pump. The test method consisted of assessing the level of free plasma haemoglobin (pHb) obtained by taking blood samples during pump operation in the operating mode (2300-2500 rpm, 5-6 l/min, pressure drop at the clamp level of 100 mmHg). Standardized haemolysis indices (NIH and MIH) were calculated based on the data obtained. The indices were calculated based on the analysis of free haemoglobin in the plasma of blood samples, haematocrit, total haemoglobin, blood flow, and pump operating time. Results. Bench tests (n = 5) revealed that the average level of free haemoglobin was 2.2 mg/%. This confirms the absolute atraumatic nature of the design of a new type of pump. The calculated values of the haemolysis indices were: NIH - 0.0013 and MIH - 1.88. This proves the fundamental possibility of using a disk-type pump as a basis for creating auxiliary circulatory devices. Conclusion. The developed methodology for assessing the mechanical stability of red blood cells allows you to give objective information about one of the most important safety criteria for auxiliary circulatory devices i.e., the level of haemolysis. The results obtained revealed that it is possible and safe to use a disk-type pump as an auxiliary circulatory device.