Abstract
Introduction Hypoxemia and hyperoxia may occur after surgery with potential related complications. The FreeO2 PostOp trial is a prospective, multicentre, randomised controlled trial that evaluates the clinical impact of automated O2 administration versus conventional O2 therapy after major abdominal or thoracic surgeries. The study is powered to demonstrate benefits of automated oxygen titration and weaning in term of oxygenation, which is an important surrogate for complications after such interventions.Methods and analysis After extubation, patients are randomly assigned to the Standard (manual O2 administration) or FreeO2 group (automated closed-loop O2 administration). Stratification is performed for the study centre and a medical history of chronic obstructive pulmonary disease (COPD). Primary outcome is the percentage of time spent in the target zone of oxygen saturation, during a 3-day time frame. In both groups, patients will benefit from continuous oximetry recordings. The target zone of oxygen saturation is SpO2=88%–92% for patients with COPD and 92%–96% for patients without COPD. Secondary outcomes are the nursing workload assessed by the number of manual O2 flow adjustments, the time spent with severe desaturation (SpO2 <85%) and hyperoxia area (SpO2 >98%), the time spent in a hyperoxia area (SpO2 >98%), the VO2, the duration of oxygen administration during hospitalisation, the frequency of use of mechanical ventilation (invasive or non-invasive), the duration of the postrecovery room stay, the hospitalisation length of stay and the survival rate.