High Flow nasal OXygen therapy in high risk patients of hypoxia undergoing diagnostic BRONCHOscopy (HiFOXy-BRONCHO):a prospective, randomized, controlled study

Background: During bronchoscopy, patients in a risk of hypoxia or in a hypoxic state have the possibility of aggravating hypoxia. The high flow nasal oxygen therapy(HFNOT) has been recently adopted as an alternative non-invasive oxygen therapy in hypoxic respiratory distress. We undertook this study to compare HFNOT with conventional oxygen therapy(COT) in high risk patients of hypoxia undergoing diagnostic bronchoscopy. Method: A prospective, randomized controlled study was conducted in a tertiary hospital from February 2014 to July 2017. The enrolled patients were older than 19 years old, planning to do diagnostic bronchoscopy and having a high risk of hypoxia. We randomized the patients in 3 groups: (1)COT, (2) sham-HFNOT(using of high flow nasal cannula circuit without real high flow) and (3)HFNOT. The primary outcome of this study was the success rate of bronchoscopy. The failure of bronchoscopy was defined as the frequency of the desaturation(less than 88%) more than 1 time or the incompletion of the planned procedure by the bronchoscopist because of hypoxia. Results: Total 136 patients were enrolled (38 for COT, 38 for sham-HFNOT, 60 for HFNOT). There was a significant difference in success rate among three groups (COT, N=25, 18.4%, vs. sham-HFNOT, N=16, 11.8% vs. HFNOT, N=39, 28.7%, p=0.048). In analyzing the difference between sham-HFNOT and HFNOT, the success rate of HFNOT group was significantly higher than sham-HFNOT (N=22, 22.5% vs. N=16, 16.3%, p=0.022). Conclusion: HFNOT could be effective for procedural success in high risk patients of hypoxia during diagnostic bronchoscopy.