Supplementary Material for: Increased Longevity of a Novel Gas Exchanger System for Low-Flow Veno-Venous Extracorporeal CO2 Removal in Acute Hypercapnic Respiratory Failure

Introduction: Low-flow veno-venous extracorporeal CO2 removal (ECCO2R) is an adjunctive therapy to support lung protective ventilation or maintain spontaneous breathing in hypercapnic respiratory failure. Low-flow ECCO2R is less invasive compared to higher flow systems, while potentially compromising efficiency and membrane lifetime. To counteract this shortcoming, a high-longevity system has recently been developed. Our hypotheses were that the novel membrane system provides runtimes up to 120 h, and CO2 removal remains constant throughout membrane system lifetime. Methods: Seventy patients with pH ≤ 7.25 and/or PaCO2 ≥9 kPa exceeding lung protective ventilation limits, or experiencing respiratory exhaustion during spontaneous breathing, were treated with the high-longevity ProLUNG system or in a control group using the original gas exchanger. Treatment parameters, gas exchanger runtime, and sweep-gas VCO2 were recorded across 9,806 treatment-hours and retrospectively analyzed. Results: 25/33 and 23/37 patients were mechanically ventilated as opposed to awake spontaneously breathing in both groups. The high-longevity system increased gas exchanger runtime from 29 ± 16 to 48 ± 36 h in ventilated and from 22 ± 14 to 31 ± 31 h in awake patients (p p 2 remained constant at 86 ± 34 mL/min (p = 0.11). Overall, PaCO2 decreased from 9.1 ± 2.0 to 7.9 ± 1.9 kPa within 1 h (p p = 0.60), and peak airway pressure could be reduced from 31.1 ± 5.1 to 27.5 ± 6.8 mbar (p Conclusion: Using a high-longevity gas exchanger system, membrane lifetime in low-flow ECCO2R could be extended in comparison to previous systems but remained below 120 h, especially in spontaneously breathing patients. Extracorporeal VCO2 remained constant throughout gas exchanger system runtime and was consistent with removal of approximately 50% of expected CO2 production, enabling lung protective ventilation despite hypercapnic respiratory failure.# 研究背景 低流量静脉-静脉体外二氧化碳清除（Low-flow veno-venous extracorporeal CO2 removal, ECCO2R）是一种辅助治疗手段，用于在高碳酸血症性呼吸衰竭患者中支持肺保护性通气或维持自主呼吸。相较于高流量系统，低流量ECCO2R的侵入性更低，但可能会降低清除效率并缩短膜式气体交换器的使用寿命。为弥补这一缺陷，近期研发出了一款高使用寿命系统。本研究的假设为：该新型膜式系统的最长运行时长可达120小时，且在膜系统整个使用寿命周期内，二氧化碳清除率保持恒定。 # 研究方法 纳入70例符合以下任一条件的患者：动脉血pH≤7.25和/或动脉血二氧化碳分压（Partial Pressure of Arterial Carbon Dioxide, PaCO2）≥9kPa、超出肺保护性通气限值，或在自主呼吸过程中出现呼吸衰竭。所有患者被分为两组，分别接受高使用寿命ProLUNG系统治疗，或使用原始气体交换器的对照组治疗。记录两组的治疗参数、气体交换器运行时长及吹扫气二氧化碳排出量（Sweep-gas Ventilation of Carbon Dioxide, VCO2），共计9806个治疗小时，并进行回顾性分析。 # 研究结果 两组中分别有25/33例与23/37例患者接受机械通气，余者均为清醒自主呼吸状态。高使用寿命系统可将机械通气患者的气体交换器运行时长从29±16小时提升至48±36小时，将清醒患者的运行时长从22±14小时提升至31±31小时（P<0.05）；吹扫气VCO2始终维持在86±34 mL/min（P=0.11）。整体而言，患者的PaCO2在1小时内从9.1±2.0 kPa降至7.9±1.9 kPa（P<0.001），气道峰压可从31.1±5.1 mbar降至27.5±6.8 mbar（P<0.05）。 # 研究结论 相较于既往系统，使用高使用寿命气体交换器系统可延长低流量ECCO2R中的膜式气体交换器使用寿命，但该时长仍未达到120小时，在自主呼吸患者中尤为明显。体外VCO2清除在整个气体交换器运行周期中保持稳定，约为预期二氧化碳产生量的50%，可在高碳酸血症性呼吸衰竭患者中实现肺保护性通气。