Evaluation of high flow nasal cannulae during endobronchial ultrasound bronchoscopy (EBUS) in high anaesthetic risk patients: a monocentric prospective study

Background: EndoBronchial UltraSound-guided TransBronchial Needle Aspiration (EBUS-TBNA) is a widely used technique in pulmonary diseases. The procedure may lead to respiratory complications that affect patient's clinical status, especially in the presence of pre-existing comorbidities. The aim of this observational study is to investigate the effectiveness of oxygen therapy administered by high flow nasal cannulae (HFNC) in this setting. Methods: Study population comprised 40 consecutive patients with high anaesthetic risk (ASA III) who underwent EBUS-TBNA at the Tor Vergata University Hospital of Rome. 20 patients were oxygenated with standard low-flow system and 20 patients with HFNC. All patients underwent deep sedation with a combination of midazolam + propofol. Results: HFNC treated patients showed significant smaller drop in O2 saturation compared to standard oxygen group (3.8 ± 5.9 vs 12.3 ± 15.3, 95% CI 0.91 to 16.14, P = 0.029). Furthermore, the lowest O2 saturation in the control group was significantly lower (83.2 ± 15.6 vs 91.4 ± 5.9, 95% CI -15.86 to -0.35, P = 0.041) requiring a higher FiO2 (oxygen fraction) increase compared to HFNC group (7.7 ± 9.7 vs 2.1 ± 6.3, 95% CI 26.16 to 66.84, P = 0.043). Episodes of desaturation were shorter in the HFNC group (90 ± 37.9 s. vs 120 ± 39.2 s., 95% CI 26.16 to 66.84, P = 0.040). Conclusions: Our results support HFNC as an effective tool to limit the severity of episodes of desaturation and hypoxia. The innovation of this work is represented by the use of HFNC in a population of complex patients at high anaesthetic risk.