Flow measurement with ultrasonic resonators at centrifugal pump head outlet

During heart surgeries, the blood circulation required for the body to be immobile and free of blood is provided by a mechanism called the Heart-Lung Machine. The heart-lung machine does its job by allowing the heart and lungs to be stopped during surgery. In addition, ECMO (Extracorporeal Membrane Oxygenation), a variant of the cardio-pulmonary bypass circuit (pump), is used as a short-term life support unit in cases of cardiac or pulmonary insufficiency. The heart-lung machine has a design consisting of roller (cylindrical) or centrifugal pump heads. ECMO has a centrifugal pump head. The flow in centrifugal pumps is proportional to the pressure in the outlet line and the flow measured from the centrifugal pump outlet must be continuously monitored by ultrasonic flowmeters as it directly affects the operation of the pump. This study was carried out to examine the flow parameters in the centrifugal pump head, which causes the least damage to the blood and can work most effectively with energy conservation principles, for use in both short-term life support devices (ECMO) and Heart-Lung machine. It was aimed to determine the flow rate measurement at the outflow point of the sentrifugal pump head prototype in the most realistic way. In the study, the prototype centrifugal pump head model we designed in Dokuz Eylul University Hospital's Depark Z.07 Flow Physiology Laboratory and Ege Dynamic A.Ş, a flowmeter with ultrasonic resonators and embedded software were used. By using mutual ultrasonic wave intake-efficiency and time of flight method, the flow rate of the liquid pumped from the system (leaving the pump head) on the prototype of the centrifugal pump head was measured precisely by means of two ultrasonic resonators placed at an angle of 45 degrees to the blood line. In the established circulation circuit, the solution with the same viscosity as the plasma was used. In order to determine the current flow measurement in the most realistic way, the data obtained with ultrasonic resonators were compared with the data obtained from an accredited flowmeter. As a result of the statistical analyzes, no significant difference was found between the two groups (measurement group and sonotec group) in terms of flow parameters (p=0.998), the measurement error margin of the ultrasonic flowmeter assembly is less than the target.