Introduction
Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive diagnostic method for mediastinal/hilar lymphadenopathies and masses [1]. During the EBUS-TBNA, all relevant lymph node stations should be evaluated and optimal results can be obtained by three aspirations per lymph node station [2]. The procedure induces cough, increases airway secretions, and reduces airway caliber. Because of these reasons, the procedure should be performed with sedation that provides both patient’s comfort and bronchoscopist’s ability for obtaining adequate tissue. Intravenous sedation (a combination of alfentanyl/fentanyl, propofol, and/or midazolam) is commonly used in EBUS-TBNA procedure. However desaturation is the major problem during sedation because sedation causes upper airway obstruction, respiratory depression and hypoventilation due to muscle relaxation [3,4]. Hypoxemia can lead to sympathetic activation and may cause tachycardia and hypertension. During bronchoscopic procedures, patients stay under spontaneous breathing and Oxygen is delivered through a mask. Arterial Oxygen saturation should be at least 90% to reduce the risk of significant arrhythmia [5]. Drugs for anesthesia or sedation can increase the severity of obstructive sleep apnea. Propofol is known to contribute to the narrowing of the upper airway by decreasing the activity of genioglossus muscle in proportion to its concentration. [6]. Continuous positive airway pressure (CPAP) has a mechanical effect that increases the intraluminal pressure of the upper airway above the positive transmural pressure of the pharynx and hypopharynx. CPAP has been shown to improve the decreased tidal volume and airflow during sedation for bronchoscopy in children [7]. Additionally, jaw-thrust and CPAP application have been shown to improve ventilation in infants under anesthesia [8]. To our knowledge, there is no study on the effect of nCPAP on Oxygen desaturation during the EBUS-TBNA. In this study, our aim was to investigate the effect of Oxygen application with nCPAP on hypoxemia during EBUS-TBNA.