Increased Longevity of a Novel Gas Exchanger System for Low-Flow Veno-Venous Extracorporeal CO(2) Removal in Acute Hypercapnic Respiratory Failure

INTRODUCTION: Low-flow veno-venous extracorporeal CO(2) removal (ECCO(2)R) is an adjunctive therapy to support lung protective ventilation or maintain spontaneous breathing in hypercapnic respiratory failure. Low-flow ECCO(2)R 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 CO(2) removal remains constant throughout membrane system lifetime. METHODS: Seventy patients with pH ≤ 7.25 and/or PaCO(2) ≥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 VCO(2) 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 < 0.0001), with longer runtime in the former (p < 0.01). VCO(2) remained constant at 86 ± 34 mL/min (p = 0.11). Overall, PaCO(2) decreased from 9.1 ± 2.0 to 7.9 ± 1.9 kPa within 1 h (p < 0.001). Tidal volume could be maintained at 5.4 ± 1.8 versus 5.7 ± 2.2 mL/kg at 120 h (p = 0.60), and peak airway pressure could be reduced from 31.1 ± 5.1 to 27.5 ± 6.8 mbar (p < 0.01). CONCLUSION: Using a high-longevity gas exchanger system, membrane lifetime in low-flow ECCO(2)R could be extended in comparison to previous systems but remained below 120 h, especially in spontaneously breathing patients. Extracorporeal VCO(2) remained constant throughout gas exchanger system runtime and was consistent with removal of approximately 50% of expected CO(2) production, enabling lung protective ventilation despite hypercapnic respiratory failure.