Pre-SAFEx: protocol for a single-centre, randomised, unblinded feasibility trial of Simultaneous Application of Flow at Extubation (SAFEx) in patients requiring intubation and ventilation for the management of acute respiratory failure

Abstract Background Failed extubation within critical care is associated with increased morbidity and mortality. Although the role of high-flow nasal therapy (HFNT) has been established post-extubation, it is not clear whether the delay in establishing HFNT after extubation adversely affects lung physiology, resulting in an increased risk of extubation failure. Early administration of HFNT may prevent lung derecruitment and reduce the rate of extubation failure. Electrical impedance tomography (EIT) is a non-invasive, non-ionising imaging method that allows continuous real-time measurement of lung physiology. Methods This is a single-centre, unblinded, randomised feasibility trial. Patients who have required intubation and ventilation for the management of acute respiratory failure will be recruited from the critical care unit at Queen Elizabeth University Hospital, Glasgow, Scotland. At the time of their planned extubation, patients will either be randomised to SAFEx extubation (where HFNT is established pre-extubation) or to standard care (where low-flow conventional oxygen therapy is established post-extubation). EIT will be used to compare the lung physiology of these two extubation strategies. Discussion This randomised feasibility trial will provide the relevant information to determine whether a multi-centre feasibility study comparing a SAFEx extubation against standard care is viable. It will also determine the feasibility of using EIT as a measure of changes in lung physiology peri-extubation. As extubation failure remains a significant burden for critical care services, with an associated lack of evidence addressing the impact that the oxygen delivery device has on the outcome of extubation in high-risk patients, this study aims to take the first step in addressing this important research question. Trial registration ClinicalTrials.Gov. Registration number: NCT05904652. Date of registration: 2023-06-15. https://clinicaltrials.gov/