The Role of High-Flow Nasal Cannula (HFNC) During Flexible Bronchoscopy in Adult Patients with Moderate Respiratory Dysfunctions: An Observational Study

<b>Background/Objectives</b>: Flexible bronchoscopy (FB) enables airway exploration and diagnosis of various respiratory pathologies, but the sedation and instrumentation required during the procedure raise oxygen demand while reducing ventilation, which can lead to hypoxemia. Conventional oxygen therapy (COT) may not adequately prevent desaturations in high-risk groups, as patients with moderate respiratory deficiency. High-flow nasal cannula (HFNC) can deliver heated, humidified oxygen at high flow rates, generating low-level positive airway pressure, improving oxygenation, reducing dead-space, and enhancing procedure tolerance. Prior studies have shown that HFNC can improve gas exchange and reduce desaturations during bronchoscopy. However, evidence remains limited for patients with moderate respiratory deficiency, who are particularly vulnerable. Evaluating the feasibility and safety of HFNC in this population is essential to guide safe procedural practice. <b>Methods</b>: A retrospective observational study including patients undergoing FB with HFNC support between January and May 2025. Inclusion criteria were BMI between 18 and 30; age > 18 years old; moderate respiratory dysfunction, defined by pulse oximetry, Pulmonary Functional Tests (PFTs) and Arterial Blood Gas (ABG) analysis. Exclusion criteria were intolerance/contraindication to HFNC. Procedures were performed under basic monitoring. Primary outcome was occurrence of severe hypoxemia (SpO2 < 90%). Secondary outcomes were needed for rescue maneuvers, interruption for conversion to other ventilatory strategies, and hemodynamic instability. <b>Results</b>: No severe desaturations were recorded, all procedures were completed without rescue maneuvers or other ventilatory strategies, and no hypoxemia occurred. Mean duration of the procedure was 9 min. Vital parameters were maintained within the normal ranges, with a mean SpO₂ during bronchoscopy of 98%. <b>Conclusions</b>: HFNC enables oxygenation and ventilation without adverse events in sedations for FB in patients with moderate respiratory deficiency.