Development of a Novel Intravenous Membrane Oxygenator.

Abstract : The Intravenous Membrane Oxygenator (IMO) at the University of Pittsburgh is intended to provide temporary and portable respiratory support to military personnel and civilians whose lungs are acutely impaired. The current IMO device consists of several hundred hollow fiber membranes (HFMs) manifolded to gas supply lines, with a helium-activated pulsating balloon within the fiber bundle for promoting mixing and enhancing gas exchange. This report describes principal progress in the following areas: (l) Development of a simplified test for characterizing gas exchange performance in IMO prototypes. The test shortens the time associated with prototype evaluation, redesign/change, and re-evaluation. (2) Testing and development of IMO Prototype D devices. Limitations to balloon-induced gas exchange enhancement were traced to inefficient pneumatic design of the helium delivery pathway, which is currently undergoing design review and modification. Preliminary modifications to the pathway resulted in significant improvement in balloon dynamics. Additionally, promising pilot work continues on direct mechanical activation of fiber movement to enhance gas exchange. (3) Evaluation of candidate hollow fiber membranes (HFHs). Procedures developed for estimating the gas permeability indicated that some composite HFMs may be unsuitable for IMO application. Other composite HFMs are being investigated, as are silicone coated porous HFMs.