Extracorporeal carbon dioxide removal for treatment of exacerbated chronic obstructive pulmonary disease (ORION): study protocol for a randomised controlled trial

Background: Hypercapnic exacerbations are severe complications of chronic obstructive pulmonary disease (COPD), characterized by negative impact on prognosis, quality of life and healthcare costs. The present standard of care for acute exacerbations of COPD is non-invasive ventilation; when it fails, the use of invasive mechanical ventilation is inevitable, but is associated with extremely poor prognosis. Extracorporeal circuits designed to remove CO2 (ECCO2R) may enhance the efficacy of NIV to remove CO2 and avoid the worsening of respiratory acidosis, which inevitably leads to failure of non-invasive ventilation. Although the use of ECCO2R for acute exacerbations of COPD is steadily increasing, solid evidence on its efficacy and safety is scarce, thus the need for a randomized controlled trial. Methods: multicenter randomized controlled unblinded clinical trial including 284 (142 per arm) patients with acute hypercapnic respiratory failure caused by exacerbation of COPD, requiring respiratory support with NIV. The primary outcome is event free survival at 28 days, a composite outcome defined by survival in absence of prolonged mechanical ventilation, severe hypoxemia, septic shock and second episode of COPD exacerbation. Secondary outcomes are incidence of endotracheal intubation and tracheostomy, intensive care and hospital length-of-stay and 90-day mortality. Discussion: Acute exacerbations of COPD represent a significant burden in terms of prognosis, quality of life and healthcare costs. Lack definite evidence despite increasing use of ECCO2R justifies a randomized trial to evaluate whether patients with acute hypercapnic acidosis not responsive to NIV should undergo invasive mechanical ventilation (with all serious related risks) or be treated with ECCO2R to avoid invasive ventilation but be exposed to possible adverse events of ECCO2R. Owing to its pragmatic nature, sample size and composite primary outcome, this trial aims at providing valuable answers to relevant questions for clinical treatment of acute exacerbations of COPD. Trial registration: ClinicalTrials.gov, NCT04582799. Registered 12 October 2020,.