A Flow Study of the Effects of Outlet Valve Angle in the Right Side of the 12cc Penn State Pediatric Total Artificial Heart
Restricted (Penn State Only)
- Author:
- Selinsky, Peter
- Area of Honors:
- Biomedical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Keefe B Manning, Thesis Supervisor
Nanyin Zhang, Thesis Honors Advisor
William Joseph Weiss, Faculty Reader - Keywords:
- Penn State
Particle image velocimetry (PIV)
pediatric ventricular assist device (PVAD)
total artificial heart (TAH)
ventricular assist device (VAD)
pediatric total artificial heart (pTAH)
right side of pediatric total artificial heart (RpTAH)
fluid dynamics
blood analog
mechanical circulatory support device (MCSD)
outlet valve angle
3D flow
rotational flow
wall washing
fluid velocity
flow loop - Abstract:
- Mechanical circulatory support devices (MCSDs) are often used as methods to treat heart disease or heart failure by reducing the stress experienced by the heart. MSCDs are commonly used as a bridge to transplant option for patients on the organ transplant waiting list. While many MCSDs have been developed and tested for adults, recently these devices have been modified and tested for pediatric patients. Pediatric patients may require single ventricular support with a ventricular assist device (VAD) or biventricular support with a total artificial heart (TAH). This study aimed to characterize the fluid dynamics within the right side of the 12cc Penn State pediatric total artificial heart (RpTAH) by varying the outlet valve angle. Particle image velocimetry (PIV) was used to quantify the fluid dynamics of the device. A blood analog fluid was used with a mock circulatory flow loop in order to properly mimic pediatric flow conditions. Four outlet valve orientations were examined; a relative 0° condition was defined based on device geometry with the remaining outlet orientations rotated in 90° intervals. The beat rate was kept at a constant 75 bpm at a mean flow rate of 0.7 L/min. Pressure and flow waveforms were determined to match physiologic flow conditions and ensure complete filling and ejection. PIV data were collected at three planes within the RpTAH. Each valve orientation demonstrated similar flow progression, beginning with an inflow jet of differing strengths in diastole and transitioning to a rotational flow. Flow transitioned from varying progressions of rotational flow to an outflow jet during systole. The outlet valve orientation had an effect on in-plane fluid velocity and the timing of rotational flow formation due to the 3D nature of flow. This 3D flow thereby affected the filling and ejection within the device. The 0° and 90° orientations displayed weak, condensed inflow jets and lacked long lasting rotational flow. The 180° outlet orientation displayed the longest lasting rotational flow region of 400 msec, with an average rotational fluid velocity higher than the other outlet angles at most time points. This large rotational flow region prevented flow stagnation and flow separation, and promoted increased wall washing over an extended period of time. The 270° orientation did not display an outstanding rotational region, but consistently displayed higher fluid velocities within the observable plane and more developed inflow and outflow jets during filling and ejection. This high fluid velocity also worked to promote increased wall washing to prevent flow stagnation along the walls of the device. Additionally, the 180° and 270° orientations consistently displayed flow field similarities to previous PVAD data. The behavior of these two outlet valve orientations demonstrated that the ideal outlet orientation lies within the range of the relative 180° and 270° orientations.