Introduction: HFNC is currently used in various settings and could provide optimal respiratory support for most bronchoscopic procedures including EBUS TBNA.
Primary objective: to describe the efficacy, complication rate and risk factors for desaturation when using HFNC during EBUS TBNA.

Methods: prospective, observational, single center study. All patients eligible for EBUS TBNA in deep sedation (RASS -4) during the 2 year study period were supported by HFNC (FiO2 0.5, flow rate 60L/min). Desaturation was defined as a persistent drop of SpO2 <88% requiring further intervention.

Results: A total of 362 patients underwent EBUS TBNA, 41.4% female and 58.6% male, with a mean age of 63.5 years. HFNC provided effective respiratory support in 343 (95.7%) cases. Desaturation occurred in 5.3% (19/362) of cases requiring laryngeal mask insertion in 12 and endotracheal intubation in 7 patients. The average BMI in the whole cohort, stable (SG) and desaturation group (DG) were 27.0, 26.8 and 29.7 with 63.5%, 57.4% and 84.2% of patients having above normal BMI, respectively. There were 21.3% (73/343) obese patients in the SG, and 47.4% (9/19) in the DG (p=0.02). Respiratory insufficiency (RI) prior to EBUS was noted in 29.6% (107/362) of total cases, 28.6% (98/343) in the SD and 47.7% (9/19) in the DG (p=0.12). Serious adverse events included 1 cardiac arrest with successful resuscitation, transient hemodynamic instability in 7, vomiting in 3 and bronchospasm in 1 case. Unexpected ICU admission was required for 3 patients.

Conclusion: HFNC provides adequate respiratory support during EBUS for most patients. However, desaturation was significantly more frequent among obese patients.