Development of a novel intravascular oxygenator catheter: Oxygen mass transfer properties across nonporous hollow fiber membranes

Abstract

Despite hypoxic respiratory failure representing a large portion of total hospitalizations and healthcare spending worldwide, therapeutic options beyond mechanical ventilation are limited. We demonstrate the technical feasibility of providing oxygen to a bulk medium, such as blood, via diffusion across nonporous hollow fiber membranes (HFMs) using hyperbaric oxygen. The oxygen transfer across Teflon® membranes was characterized at oxygen pressures up to 2 bars in both a stirred tank vessel (CSTR) and a tubular device mimicking intravenous application. Fluxes over 550 ml min −1 m −2 were observed in well-mixed systems, and just over 350 ml min −1 m −2 in flow through tubular systems. Oxygen flux was proportional to the oxygen partial pressure inside the HFM over the tested range and increased with mixing of the bulk liquid. Some bubbles were observed at the higher pressures (1.9 bar) and when bulk liquid dissolved oxygen concentrations were high. Highfrequency ultrasound was applied to detect and count individual bubbles, but no increase from background levels was detected during lower pressure operation. A conceptual model of the oxygen transport was developed and validated. Model parametric sensitivity studies demonstrated that diffusion through the thin fiber walls was a significant resistance to mass transfer, and that promoting convection around the fibers should enable physiologically relevant oxygen supply. This study indicates that a device is within reach that is capable of delivering greater than 10% of a patient's basal oxygen needs in a configuration that readily fits intravascularly.

Intravascular Gas Exchange: Physiology, Literature Review, and Current Efforts

“…23 The diffusion gradient can be maximized by using 100% O 2 sweep gas flowing within the HFMs and can further be increased by using hyperbaric pressures. 24 Whereas porous materials (Fig. 2A) inherently have high gas permeability, the risk of bubble formation via convective gas transfer limits the sweep gas to atmospheric pressures.…”

“…The IntraVascular Membrane Oxygenator catheter currently in development by our team is the most recent published effort at developing a respiratory assist catheter. 24 In contrast to previous attempts at intravascular gas exchange, this novel approach relies specifically on hyperbaric O 2 to generate a large driving concentration gradient for diffusion across nonporous amorphous fluoropolymer HFMs rather than relying solely on a large surface area. This device is only intended to deliver O 2 , the primary deficit in most forms of acute lung injury.…”

A hydrogel–fiber–hydrogel composite scaffold based on silk fibroin with the dual‐delivery of oxygen and quercetin

“…OGBs are encapsulated mostly in polymeric substrates to reduce the possibility of burst oxygen generation and byproducts release (de Sousa Araújo et al, 2021). Some polymers that have been utilized as polymeric substrates for OGBs are poly(lactide‐coglycolide) (Daneshmandi & Laurencin, 2020), polylactic acid (Khorshidi et al, 2021), poly(trimethylene carbonate) (Steg et al, 2017), polycaprolactone (Guaccio et al, 2011), poly(N‐vinylpyrrolidone), elastomeric antioxidant polyurethane (Shiekh et al, 2018), polydimethylsiloxane (Pedraza et al, 2012), polytetrafluoroethylene (Farling et al, 2021), and gelatin methacryloyl (Alemdar et al, 2016). The hydrophobic biopolymers are suggested for OGBs fabrication since this structure could slow down the oxygen generation and delivery and provide an extended supply of O 2 .…”