Rationale: We developed an innovative, minimally invasive, highly efficient extracorporeal CO 2 removal (ECCO 2 R) technique called respiratory electrodialysis (R-ED).Objectives: To evaluate the efficacy of R-ED in controlling ventilation compared with conventional ECCO 2 R technology.Methods: Five mechanically ventilated swine were connected to a custom-made circuit optimized for R-ED, consisting of a hemofilter, a membrane lung, and an electrodialysis cell. Electrodialysis regionally modulates blood electrolyte concentration to convert bicarbonate to CO 2 before entering the membrane lung, enhancing membrane lung CO 2 extraction. All animals underwent three repeated experimental sequences, consisting of four steps: baseline (1 h), conventional ECCO 2 R (2 h), R-ED (2 h), and final NO-ECCO 2 R (1 h). Blood and gas flow were 250 ml/min and 10 L/min, respectively. Tidal volume was set at 8 ml/kg, and respiratory rate was adjusted to maintain arterial PCO 2 at 50 mm Hg.Measurements and Main Results: During R-ED, chloride and H 1 concentration increased in blood entering the membrane lung, almost doubling CO 2 extraction compared with ECCO 2 R (112 6 6 vs. 64 6 5 ml/min, P , 0.001). Compared with baseline, R-ED and ECCO 2 R reduced minute ventilation by 50% and 27%, respectively. Systemic arterial gas analyses remained stable during the experimental phases. No major complication occurred, but there was an increase in creatinine level.Conclusions: In this first in vivo application, we proved electrodialysis feasible and effective in increasing membrane lung CO 2 extraction. R-ED was more effective than conventional ECCO 2 R technology in controlling ventilation. Further studies are warranted to assess the safety profile of R-ED, especially regarding kidney function.Keywords: extracorporeal circulation; carbon dioxide; respiratory insufficiency; hypercapnia At a Glance CommentaryScientific Knowledge on the Subject: Extracorporeal CO 2 removal (ECCO 2 R) has been suggested for the treatment of patients with acute and chronic respiratory failure. The current ECCO 2 R technology, although perfected compared to the past, still has room for improvement.What This Study Adds to the Field: We developed respiratory electrodialysis, an innovative extracorporeal CO 2 removal technique that selectively modulates pH and electrolyte concentration and highly enhances CO 2 removal by applying an electrical field to blood. Respiratory electrodialysis, requiring a minimally invasive approach, could greatly affect the way we treat patients suffering from respiratory failure and other conditions.

To minimize CO(2) rebreathing during disconnection of the fresh gas supply while performing helmet CPAP, it is desirable to utilize large helmets with a large anti-suffocation valve. Monitoring and alarm systems should be employed for safe application of helmet CPAP.

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Gas exchange capabilities of polymethylpentene membrane lungs (MLs) worsen over time. ML deterioration is related to protein deposit and clot formation. Condensation and trapping of water vapor inside ML hollow fibers might affect ML performances as well. Increasing sweep gas flow (GF) could remove such fluid. The purpose of this study was to evaluate the effects on ML gas exchange of a recruitment maneuver (RM) based on a brief increase in GF, during veno-venous ECMO support. Short-term (15 min) effects of 20 RMs were assessed. RM raised ML CO2 removal from 149 ± 37 to 174 ± 41 ml/min (p < 0.001). Conversely, RM did not improve ML O2 transfer (155 ± 31 and 158 ± 31 ml/min before and after RM, respectively). ML outlet pCO2 decreased after RM from 51.2 ± 5.8 to 45.8 ± 5.4 mmHg (p < 0.001), while ML outlet pO2 increased from 520 ± 61 to 555 ± 51 mmHg (p < 0.001). Both ML dead space and shunt fractions decreased from 47.8 ± 15.3 to 29.6 ± 14.7 % (p < 0.001) and from 8.8 ± 4.2 to 7.0 ± 3.8 % (p < 0.001), respectively. Furthermore, a subset of 5 RMs was evaluated on a 6-h time frame. The beneficial effects on ML performances due to the RM gradually diminished and waned over a 6-h interval after the RM. The RM improved ML CO2 removal substantially, albeit temporarily. ML oxygenation performance was marginally affected.

collected and interpreted data, and revised the manuscript; D.D. performed surgery on animals; S.G., L.G. and A.P. interpreted data and revised the manuscript. All authors gave final approval of the version to be published and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy and integrity of any part of the work are appropriately investigated and resolved.