Utilization and outcomes of extracorporeal CO₂ removal (ECCO₂R): Systematic review and meta-analysis of arterio-venous and veno-venous ECCO₂R approaches

Introduction: Extracorporeal carbon dioxide removal (ECCO₂R) provides respiratory support to patients suffering from hypercapnic respiratory failure by utilizing an extracorporeal shunt and gas exchange membrane to remove CO₂ from either the venous (VV-ECCO₂R) or arterial (AV-ECCO₂R) system before return into the venous site. AV-ECCO₂R relies on the patient's native cardiac function to generate pressures needed to deliver blood through the extracorporeal circuit. VV-ECCO₂R utilizes a mechanical pump and can be used to treat patients with inadequate native cardiac function. We sought to evaluate the existing evidence comparing the subgroups of patients supported on VV and AV-ECCO₂R devices. Methods: A literature search was performed to identify all relevant studies published between 2000 and 2019. Demographic information, medical indications, perioperative variables, and clinical outcomes were extracted for systematic review and meta-analysis. Results: Twenty-five studies including 826 patients were reviewed. 60% of patients (497/826) were supported on VV-ECCO₂R. The most frequent indications were acute respiratory distress syndrome (ARDS) [69%, (95%CI: 53%–82%)] and chronic obstructive pulmonary disease (COPD) [49%, (95%CI: 37%–60%)]. ICU length of stay was significantly shorter in patients supported on VV-ECCO₂R compared to AV-ECCO₂R [15 (95%CI: 7–23) vs. 42 (95%CI: 17–67) days, p = 0.05]. In-hospital mortality was not significantly different [27% (95%CI: 18%–38%) vs. 36% (95%CI: 24%–51%), p = 0.26]. Conclusion: Both VV and AV-ECCO₂R provided clinically meaningful CO₂ removal with comparable mortality.