Department of Civil & Environmental Engineering, Duke University, Durham, North Carolina, USA.
Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA.
Biotechnol Bioeng. 2021 Jan;118(1):345-356. doi: 10.1002/bit.27574. Epub 2020 Oct 7.
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 m were observed in well-mixed systems, and just over 350 ml min m 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. High-frequency 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.
尽管低氧性呼吸衰竭占全球总住院人数和医疗保健支出的很大一部分,但除机械通气以外的治疗选择有限。我们展示了通过使用高压氧使非多孔中空纤维膜(HFMs)扩散来向大量介质(如血液)供氧的技术可行性。在搅拌罐(CSTR)和模拟静脉应用的管状装置中,在高达 2 巴的氧气压力下,对特氟龙®膜的氧气传递进行了表征。在混合良好的系统中观察到超过 550 ml·min-1·m的通量,在流动通过管状系统中则略高于 350 ml·min-1·m。氧气通量与测试范围内 HFM 内的氧气分压成正比,并随主体液体的混合而增加。在较高压力(1.9 巴)和主体液体溶解氧浓度较高时,观察到一些气泡。高频超声用于检测和计数单个气泡,但在较低压力下运行时,未检测到背景水平的增加。开发并验证了氧气传输的概念模型。模型参数敏感性研究表明,通过纤维壁的扩散是传质的一个重要阻力,促进纤维周围的对流应能实现生理相关的氧气供应。这项研究表明,一种能够以易于血管内的方式输送超过患者基础氧气需求 10%的装置是可行的。