Additional file 1: of High flow nasal oxygen after bariatric surgery (OXYBAR), prophylactic post-operative high flow nasal oxygen versus conventional oxygen therapy in obese patients undergoing bariatric surgery: study protocol for a randomised controlled pilot trial FultonRachel MillarJonathan MerzaMegan JohnstonHelen CorleyAmanda FaulkeDaniel RapchukIvan TarpeyJoe LockiePhilip LockieShirley FraserJohn 2018 SPIRIT 2013 checklist: recommended items to address in a clinical trial protocol and related documents. (DOCX 41 kb)