Percutaneous Respiratory Assist Catheter

本提案的目的是开发一种经皮呼吸辅助导管（PRAC），可以插入静脉系统，为需要短期（少于1-2周）呼吸辅助的患者提供独立于肺部的辅助呼吸支持。PRAC将被设计用于经皮插入外周静脉并放置在中心静脉系统中，在那里它将暴露于所有返回心脏的血液中。PRAC将包含一个圆柱形的微孔中空纤维膜，编织成织物，包裹在气球周围。气球被氦气脉冲，并通过泵送血液通过中空纤维的速度大大超过了在腔静脉中存在的速度，从而加强了气体交换。该项目的具体目标是：1。制作插入直径为25-28 Fr （8-9 mm）的候选PRAC装置，并在体外测试环中评估功能传质特性。我们将确定PRAC的气体交换性能如何取决于关键操作和设计参数。2. 评估和优化PRAC中的球囊脉动以改善气体交换。我们将主要探索气球几何形状和气球脉动模式的变化，我们将使用流动可视化、局部气体张力测量和计算模拟来帮助指导我们的设计开发。3. 进行PRAC的急性小腿植入，以评估原位气体交换功能以及与短期植入相关的任何不利的解剖、生理和生物相容性影响。我们还将评估候选PRAC设计在体外的溶血潜力，使用牛血液在bench flow loop中。我们的目标是一种经皮辅助导管，它可以在无氧状态下提供75- 85 ml/min的肺外CO2去除，可以作为急性肺衰竭（ARDS，肺炎）或急性慢性肺衰竭（COPD伴加重）患者的辅助或替代现有治疗。

The objective of this proposal is to develop a percutaneous respiratory assist catheter (PRAC) that can be inserted into the venous system to provide supplemental breathing support, independent of the lungs, for patients requiring short- term (less than 1-2 weeks) respiratory assistance. The PRAC will be designed for percutaneous insertion into a peripheral vein and placement in the central venous system, where it will be exposed to all the blood returning to the heart. The PRAC will incorporate a cylindrical bundle of microporous hollow fiber membranes woven as a fabric that is wrapped around a balloon. The balloon is pulsed with helium and enhances gas exchange by pumping blood past the hollow fibers at velocities much greater than would otherwise exist in the vena cava. The specific aims of the project are to: 1. Fabricate candidate PRAC devices with insertional diameters of 25-28 Fr (8-9 mm) and evaluate the functional mass transfer characteristics in an in-vitro test loop. We will establish how the gas exchange performance of the PRAC depends on key operating and design parameters. 2. Evaluate and optimize balloon pulsation in the PRAC to improve gas exchange. We will principally explore changes in balloon geometry and balloon pulsation mode, and we will use flow visualization, local gas tension measurements, and computational simulations to help guide our design development. 3. Perform acute calf implants of the PRAC to assess the gas exchange functionality in-situ and any adverse anatomical, physiological and biocompatibility effects associated with short- term implantation. We will also evaluate the hemolysis potential of candidate PRAC designs in-vitro using bovine blood in a bench flow loop. Our target is a percutaneous assist catheter that can provide 75- 85 ml/min of extrapulmonary CO2 removal at normocapnia and that could be used as an adjuvant or replacement to existing therapy for patients with acute lung failure (ARDS, pneumonia) or acute on chronic lung failure (COPD with exacerbation).