Modified High Flow Nasal Cannula Oxygen Therapy During Bronchoscopy

A recent study tested the hypothesis that modified high-flow nasal cannula (HFNC) oxygen therapy would decrease the proportion of patients with a single moment of peripheral arterial oxygen saturation (SpO₂) of less than 90% during bronchoscopy. Study results were recently published in BMC Pulmonary Medicine.

This single-center, prospective randomized controlled clinical trial (ClinicalTrials.gov Identifier: NCT02606188) compared the use of a modified high‑flow nasal cannula oxygen therapy (ie, using a single cannula applied to 1 nostril) with conventional oxygen therapy in hospitalized patients in need of diagnostic bronchoscopy. The primary study outcome was the rate of patients with at least a single drop in peripheral arterial oxygen saturation below 90% during bronchoscopy; the secondary endpoint was duration of bronchoscopy.

Among the 812 patients recruited to the study, 406 were randomized to the modified high‑flow nasal cannula oxygen therapy while 406 were randomized to the conventional oxygen therapy group. A total of 24 patients were unable to complete the bronchoscopy and were excluded from analysis. In the primary study outcome, the proportion of patients with a single moment of peripheral arterial oxygen saturation less than 90% during bronchoscopy in the modified high‑flow nasal cannula group was significantly lower than that in the conventional oxygen therapy group (12.5% vs 28.8%, P <.001). The duration of bronchoscopy, the secondary outcome, was significantly shorter in the HFNC group vs conventional oxygen therapy group (685 vs 800 seconds, respectively, P <.001).

Researchers found no significant differences in the fraction of inspired oxygen between the 2 groups. Notably, the lowest SpO₂ during bronchoscopy and 5 minutes after bronchoscopy in the modified HFNC group was significantly higher than that in the conventional oxygen therapy group. Multivariate analysis showed that independent risk factors for hypoxemia during bronchoscopy in the modified HFNC group were a baseline forced vital capacity (FVC) of less than 2.7 L and a volume of fluid instilled of greater than 60 ml.

The study authors wrote, “The findings from this randomized controlled trial suggest that a modified HFNC could decrease the proportion of patients with a single moment of SpO₂ [less than] 90% during bronchoscopy and shorten the duration of bronchoscopy.” They added, “A lower baseline FVC and large-volume [bronchoalveolar lavage] may predict hypoxemia during bronchoscopy with a modified HFNC.”

Reference

Wang R, Li HC, Li XY, et al. Modified high-flow nasal cannula oxygen therapy versus conventional oxygen therapy in patients undergoing bronchoscopy: a randomized clinical trial. BMC Pulm Med. 2021;21(1):367. doi:10.1186/s12890-021-01744-8