Should high-flow through nasal cannula be used during bronchoscopy in critically ill patients with hypoxemic acute respiratory failure?

Flexible fiberoptic bronchoscopy (FOB) is an invasive procedure with diagnostic and/or therapeutic purposes commonly used in critically ill patients. FOB may be complicated by desaturation, onset or worsening of the respiratory failure, and hemodynamic instability due to cardio-respiratory alterations occurring during the procedure. Increasing evidences suggest the use of high-flow through nasal cannula (HFNC) over conventional oxygen therapy (COT) in critically ill patients with acute respiratory failure (ARF). Indeed, HFNC has a rationale and possible physiologic advantages, even during FOB. However, to date, evidences in favor of HFNC over COT or continuous positive airway pressure (CPAP) or non-invasive ventilation (NIV) during FOB are still weak. Nonetheless, in critically ill patients with hypoxemic ARF, the choice of the oxygenation strategy during a FOB is challenging. Based on a review of the literature, HFNC may be preferred over COT in patients with mild to moderate hypoxemic ARF, without cardiac failure or hemodynamic instability. On the opposite, in critically ill patients with more severe hypoxemic ARF or in the presence of cardiac failure or hemodynamic instability, CPAP or NIV, applied with specifically designed interfaces, may be preferred over HFNC.