Effects of extracorporeal CO₂ removal on gas exchange and ventilator settings: a systematic review and meta-analysis

A systematic review and meta-analysis to evaluate the impact of extracorporeal carbon dioxide removal (ECCO₂R) on gas exchange and respiratory settings in critically ill adults with respiratory failure.

We conducted a comprehensive database search, including observational studies and randomized controlled trials (RCTs) from January 2000 to March 2022, targeting adult ICU patients undergoing ECCO₂R. Primary outcomes were changes in gas exchange and ventilator settings 24 h after ECCO₂R initiation, estimated as mean of differences, or proportions for adverse events (AEs); with subgroup analyses for disease indication and technology. Across RCTs, we assessed mortality, length of stay, ventilation days, and AEs as mean differences or odds ratios.

A total of 49 studies encompassing 1672 patients were included. ECCO₂R was associated with a significant decrease in PaCO₂, plateau pressure, and tidal volume and an increase in pH across all patient groups, at an overall 19% adverse event rate. In ARDS and lung transplant patients, the PaO₂/FiO₂ ratio increased significantly while ventilator settings were variable. "Higher extraction" systems reduced PaCO₂ and respiratory rate more efficiently. The three available RCTs did not demonstrate an effect on mortality, but a significantly longer ICU and hospital stay associated with ECCO₂R.

ECCO₂R effectively reduces PaCO₂ and acidosis allowing for less invasive ventilation. "Higher extraction" systems may be more efficient to achieve this goal. However, as RCTs have not shown a mortality benefit but increase AEs, ECCO₂R's effects on clinical outcome remain unclear. Future studies should target patient groups that may benefit from ECCO₂R. PROSPERO Registration No: CRD 42020154110 (on January 24, 2021).