Low-flow veno-venous extracorporeal CO 2 removal (ECCO 2R) is an adjunctive therapy to support lung protective ventilation or maintain spontaneous breathing in hypercapnic respiratory failure. Low-flow ECCO 2R 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.
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.
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).
Using a high-longevity gas exchanger system, membrane lifetime in low-flow ECCO 2R 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.