Development of a new disposable pulsatile pump for cardiopulmonary bypass: computational fluid-dynamic design and in vitro tests.

A newly conceived blood pump for pulsatile cardiopulmonary bypass (CPB) is presented. The new device's main design features (fully disposable pumping head with ring shaped valves) were intended to overcome the factors that today limit the use of pulsatile blood pumps, i.e., the complexity and costs of devices. The pump was designed and analyzed by means of three-dimensional computational models, including solid computer assisted design of the pumping head and computational fluid-dynamic (CFD) analyses of the fluid domain and of its interaction with deformable components. A prototype of the device, integrated with the venous reservoir, was built to perform hydraulic in vitro tests with aims of both validating CFD results and verifying the new device's pumping behavior. Functional evaluation of the pump was carried out by using the device in a model circuit made with standard CPB components plus a mock hydraulic bench representing an adult patient's systemic circulation. A roller pump used in pulsatile mode (RP-PM) was used for comparison. At a 5 L/min flow rate, the pulsatile hydraulic power (<Wpuls>) delivered to the patient was approximately 15 mW for the RP-PM. The new pump proved to be able to deliver <Wpuls> up to 40 mW, thus providing a more physiological condition, closer to the <Wpuls> delivered by the natural heart (90-140 mW).