vitro flow visualization of the pulmonary circulation

ABSTRACT

Flow field of the pulmonary circulation has been investigated by in vitro pulsatile and steady flow visualization in simulation models. A couple of counter-rotating secondary flows were symmetric about the centerline in the normal valve. As the pulmonic valve became more stenotic, the two counter-rotating secondary flows in both the left pulmonary arteries [LPA] and right pulmonary arteries [RPA] were no longer symmetric. With a normal Hancock porcine aortic valve inside the extracardiac conduit, the flow of the proximal conduit was spiral, and that of the distal portion was axial. In stenosed Hancock porcine aortic valve loaded conduit, the flow was a continuous spiral. Studies on cavopulmonary connection models showed that energy savings were more evident at the 5050 right / left pulmonary artery ratio, and the energy losses increased in proportion to total flow rates. A 60° to 90° anastomotic angle between the subclavian artery and the graft of Blalock-Taussig shunt could result in favorable pulmonary artery flow distribution and peak pressure. Simulations in the Norwood circulation model showed that larger shunts rendered an increased cardiac output to the lungs. In order to determine the idealistic cardiac surgical technical conditions, in vitro flow visualization study is a primarily useful tool in optimizing the flow and diminishing the energy losses