Prevention of hypoxemia during endobronchial ultrasound-guided transbronchial needle aspiration: Usefulness of high-flow nasal cannula

Abstract

Background: Hypoxemia during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is often encountered even in patients without respiratory impairment before the procedure. The aim of this study was to evaluate the efficacy of a high-flow nasal cannula (HFNC) in preventing hypoxemia during EBUS-TBNA.

Methods: The present investigation was designed as a prospective pilot study. Eligible subjects were adults who could undergo EBUS-TBNA under intravenous midazolam sedation. The main exclusion criteria were as follows: age > 80 years with impaired oxygenation and peripheral oxygen saturation (SpO₂) < 95% at room air. The primary outcome was the oxygenation level during the procedure. Cutaneous carbon dioxide tension (PcCO₂) and complications were evaluated as secondary outcomes. HFNC use was started at an inspired O₂ fraction of 30% and was titrated to maintain SpO₂ over 90%. The lowest SpO₂ values during EBUS-TBNA were retrospectively compared between patients who underwent HFNC and those were given a conventional nasal cannula as a historical control group.

Results: Twelve patients received HFNCs. The mean lowest SpO₂ during the procedure was 93%. Although the mean SpO₂ tended to decrease in the early stages, it remained over 90% throughout the procedure. The mean highest PcCO₂ was 39 mmHg (range, 30-46 mmHg). There were no major complications. In patients who underwent EBUS-TBNA using a conventional nasal cannula, the mean lowest SpO₂ was 88%, which was significantly lower than that in the HFNC cases (p = 0.005).

Conclusion: HFNC could be an effective and safe device for prevention of hypoxemia during EBUS-TBNA.

Keywords: Endobronchial ultrasound-guided transbronchial needle aspiration; High-flow nasal cannula; Intravenous sedation; Midazolam.