10.1184/R1/6096932.v1
Rebecca E. Schewe
Rebecca E.
Schewe
Khalil M. Khanafer
Khalil M.
Khanafer
Ryan A. Orizondo
Ryan A.
Orizondo
Keith Cook
Keith
Cook
Thoracic artificial lung impedance studies using computational fluid dynamics and in vitro models.
Carnegie Mellon University
2012
Artificial Organs
Biomedical Engineering
Cardiac Output
Electric Impedance
Finite Element Analysis
Humans
Hydrodynamics
Lung
Lung Transplantation
Models
Biological
Pulmonary Circulation
2012-03-01 00:00:00
Journal contribution
https://kilthub.cmu.edu/articles/journal_contribution/Thoracic_artificial_lung_impedance_studies_using_computational_fluid_dynamics_and_in_vitro_models_/6096932
<p>Current thoracic artificial lungs (TALs) possess blood flow impedances greater than the natural lungs, resulting in abnormal pulmonary hemodynamics when implanted. This study sought to reduce TAL impedance using computational fluid dynamics (CFD). CFD was performed on TAL models with inlet and outlet expansion and contraction angles, θ, of 15°, 45°, and 90°. Pulsatile blood flow was simulated for flow rates of 2-6 L/min, heart rates of 80 and 100 beats/min, and inlet pulsatilities of 3.75 and 2. Pressure and flow data were used to calculate the zeroth and first harmonic impedance moduli, Z(0) and Z(1), respectively. The 45° and 90° models were also tested in vitro under similar conditions. CFD results indicate Z(0) increases as stroke volume and θ increase. At 4 L/min, 100 beats/min, and a pulsatility of 3.75, Z(0) was 0.47, 0.61, and 0.79 mmHg/(L/min) for the 15°, 45°, and 90° devices, respectively. Velocity band and vector plots also indicate better flow patterns in the 45° device. At the same conditions, in vitro Z (0) were 0.69 ± 0.13 and 0.79 ± 0.10 mmHg/(L/min), respectively, for the 45° and 90° models. These Z(0) are 65% smaller than previous TAL designs. In vitro, Z(1) increased with flow rate but was small and unlikely to significantly affect hemodynamics. The optimal design for flow patterns and low impedance was the 45° model.</p>