System and Method for Traversing Pipes

A system and method is provided for traversing inside one or more pipes. In an embodiment, a fluid is injected into the one or more pipes thereby promoting a fluid flow. An inspection device is deployed into the one or more pipes at least partially filled with a flowing fluid. The inspection device comprises a housing wherein the housing is designed to exploit the hydrokinetic effects associated with a fluid flow in one or more pipes as well as maneuver past a variety of pipe configurations. The inspection device may contain one or more sensors capable of performing a variety of inspection tasks

Intraventricular flow dynamics and thrombosis risk with a left ventricular assist device using accelerated thrombosis modeling and stress-blended eddy simulation

Thrombosis remains a significant complication in blood-contacting medical devices. Computational studies on flow dynamics within a left ventricular assist device (LVAD) supported left ventricle (LV) have been conducted, yet there is a lack of detailed models capable of comprehensive LV flow dynamics analysis to predict localized thrombus risk. This study aimed to address these gaps by employing a scale-resolving turbulence model combined with an accelerated thrombosis model for intraventricular flow disturbed by an LVAD. A patient-specific LV model of a post-VAD patient was implanted with a HeartMate3 cannula. A complete heart failure scenario with a 5 L/min LVAD outflow and rigid walls was developed. The blood turbulence field was modeled using a Stress-blended eddy simulation turbulence model. The accelerated thrombosis model involved three convection-diffusion equations to trace the non-activated platelets, activated platelets, and adenosine diphosphate. Results were compared with residence time, a simplified thrombosis index commonly used in the literature. Blood residence time peaked at 7.5 s along the cannula surface and exceeded 3.5 s around the aortic root and behind the mitral leaflets. Concurrently, the scaled activated platelet concentration reached its maximum value on the cannula surface toward the cannula outlet. The activation rates of platelets indicate a negligible activation, suggesting that thrombosis occurring in the LV of LVAD patients is primarily due to prolonged blood residence, leading to increased coagulation.</p

Improved Drainage Cannula Design to Reduce Thrombosis in Veno-Arterial Extracorporeal Membrane Oxygenation

Thrombosis is a potentially life-threatening complication in veno-arterial extracorporeal membrane oxygenation (ECMO) circuits, which may originate from the drainage cannula due to unfavorable blood flow dynamics. This study aims to numerically investigate the effect of cannula design parameters on local fluid dynamics, and thus thrombosis potential, within ECMO drainage cannulas. A control cannula based on the geometry of a 17 Fr Medtronic drainage cannula concentrically placed in an idealized, rigid-walled geometry of the right atrium and superior and inferior vena cava was numerically modeled. Simulated flow dynamics in the control cannula were systematically compared with 10 unique cannula designs which incorporated changes to side hole diameter, the spacing between side holes, and side hole angles. Local blood velocities, maximum wall shear stress (WSS), and blood residence time were used to predict the risk of thrombosis. Numerical results were experimentally validated using particle image velocimetry. The control cannula exhibited low blood velocities (59 mm/s) at the cannula tip, which may promote thrombosis. Through a reduction in the side hole diameter (2 mm), the spacing between the side holes (3 mm) and alteration in the side hole angle (30° relative to the flow direction), WSS was reduced by 52%, and cannula tip blood velocity was increased by 560% compared to the control cannula. This study suggests that simple geometrical changes can significantly alter the risk of thrombosis in ECMO drainage cannulas