Comparison of high-flow nasal cannula and conventional oxygen therapy for high-risk patients during bronchoscopy examination: protocol for a randomized controlled trial

Abstract IntroductionHigh-flow nasal cannula (HFNC) has been proven to improve oxygenation and avoid intubation in hypoxemic patients. It has also been utilized during endoscopy examination to reduce the incidence of hypoxia. However, little is known about the effects of HFNC versus conventional oxygen therapy (COT) on oxygenation during bronchoscopy examination via nasal route; particularly, no study has compared the use of HFNC with that of COT at similar FIO2 during bronchoscopy examination for patients who have high-risk factors of desaturation during bronchoscopy examination. Methods and analysisThis randomized controlled trial will be implemented in four centers. Patients who have high-risk factors including hypoxemia, hypercapnia, morbid obesity, and narrow airway will be enrolled to use HFNC or COT during bronchoscopy examination. In the HFNC group, the gas flow will be set at the maximal level that the patient can tolerate with a fraction of inspired oxygen (FIO2) at 0.45, with one prong of the nasal cannula occluded and left outside the nose; while in the COT group, oxygen flow will be set at 6 L/min via a single-prong nasal cannula. After 5 min pre-oxygenation, the bronchoscope will be inserted via nasal route. Vital signs, oxygenation (SpO2), and transcutaneous CO2 (PtCO2) will be continuously monitored. Incidence of hypoxemia, defined as SpO2 < 90% for 10 seconds during bronchoscopy examination, and the need for treatment escalation will be compared in the two groups. DiscussionHypoxia is a common complication of bronchoscopy, our study attempted to demonstrate that HFNC may reduce the probability of hypoxia during bronchoscopy in high-risk patients. The results will be disseminated through peer-reviewed journals, national and international conferences.Trial registration http://www.chictr.org.cn/: ChiCTR2100055038. Registered on 31 December 2021URL of the trial registry record：http://www.chictr.org.cn/showproj.aspx?proj=146692