Small intrapulmonary artery lung prototypes. Mathematical modeling of gas transfer.

Two diffusion models have been developed to analyze gas transfer data previously measured in an intravascular artificial lung consisting of a central gas supply catheter from which are tethered a large number of blind-ended microporous fibers of equal length. A convective-diffusion model (CD) describes the countercurrent transfer of a binary gas pair when gas is supplied at constant pressure conditions, and a well mixed (WM) cycled pressure model predicts transfer when the gas supply pressure is time cycled between compression and vacuum conditions. Regression of gas to gas and liquid to gas excretion data with the CD model resulted in estimates of the liquid phase mass transfer coefficient kAI.

Polysulfone coating for hollow fiber artificial lungs operated at hypobaric and hyperbaric pressures.

Carbon dioxide transfer is increased when the gas phase of a hollow fiber membrane lung is operated at hypobaric pressures. Oxygen transfer is augmented by hyperbaric pressures. However, uncoated hollow fibers transmit gas bubbles into the blood when operated at a pressure greater than 800 mmHg and may have increased plasma leakage when operated at hypobaric pressures.

Gas transport in the intracorporeal oxygenator with woven tubes.

The woven tubes membrane oxygenator is a suitable configuration for the intracorporeal membrane oxygenator because of a high gas exchange performance and a compact packing of tubing. In this study the oxygen transfer performance of woven tubes was evaluated by an in vitro experiment with an external perfusion mode; the blood flow is outside of the tubes in order to reveal the feasibility of designing the intravascular oxygenator (IVOX) by the woven tubes. The oxygen transfer efficiency of the external perfusion mode is superior to that with the internal perfusion mode because of the larger convective mixing effect on the external surface of the tubes.

Effects of blood phase oscillation on gas transfer in a microporous intravascular lung.

It may be possible to design an intravascular membrane lung with gas transfer properties augmented by the natural flow oscillations in the venous and pulmonary circulation caused by the beating heart and ventilatory movements. The authors used a simple dye visualization technique, the Pierce-Donachy assist pump, and mass spectrometry to investigate these effects on membrane lungs made with tethered, blind-ended, microporous, polypropylene fibers using in vitro tests in water saturated with O2, CO2, and He. Prototypes were constructed on a 7.

Small intrapulmonary artery lung prototypes: design, construction, and in vitro water testing.

Blind-ended, hollow fibers mounted on a pulmonary artery catheter may allow O2 and CO2 transfer in the vena cava, right ventricle, and pulmonary artery. The effects of fiber length, manifold number, and gas oscillation on mass and momentum transfer with water perfusate using mass spectrometry and mass flow controllers were studied. Manifolds with 112-196 microporous polypropylene fibers were mounted on 8 Fr multiple lumen, commercially available pulmonary artery catheters.