A prospective randomized comparative study of high-flow nasal cannula oxygen and non-invasive ventilation in hypoxemic patients undergoing diagnostic flexible bronchoscopy

Abstract

© Journal of Thoracic Disease. All rights reserved. Background: Although oxygen supplementation during bronchoscopy in patients with pre-existing hypoxemia is provided, adequacy of oxygenation may not be achieved, resulting in the occurrence of respiratory failure that requires endotracheal tube intubation. The purpose of this study was to compare high-flow nasal cannula (HFNC) with non-invasive ventilation (NIV) in patients with pre-existing hypoxemia undergoing flexible bronchoscopy (FB) on the ability to maintain oxygen saturation during bronchoscopy. Methods: A prospective randomized study was conducted in patients who had hypoxemia [defined as partial pressure of arterial oxygen (PaO2) less than 70 mmHg at room air] and required FB for the diagnosis of abnormal pulmonary lesions. Patients were randomized to receive either HFNC or NIV during FB. The primary outcome was the lowest oxygen saturation level during FB. Results: Fifty-one patients underwent randomization to HFNC (n=26) or NIV (n=25). Baseline characteristics in terms of age, Simplified Acute Physiologic Score II values, and cardiorespiratory parameters were similar in both groups. After receiving HFNC or NIV, oxygen saturation as measured by pulse oximeter (SpO2) increased to greater than 90% in all cases. During FB, although the lowest SpO2 was similar in both groups, the lowest SpO2 <90% tended to occur more often in the HFNC group (34.6% vs. 12.0%; P=0.057). In patients with baseline PaO2 <60 mmHg on ambient air, a decrease in PaO2 from preprocedure to the end of FB was less in the NIV group (-13.7 vs. -57.0 mmHg; P=0.019). After FB, the occurrence of SpO2 <90% was 15.4% and 4.0% in the HFNC group and NIV group, respectively (P=0.17). Conclusions: In overall, NIV and HFNC provided the similar effectiveness in prevention of hypoxemia in hypoxemic patients undergoing FB. However, in subgroup analysis, NIV provided greater adequacy and stability of oxygenation than HFNC in patients with baseline PaO2 <60 mmHg on ambient air.