Comparison of Two Needle Agitation Strategies in Endobronchial Ultrasound-guided Transbronchial Needle Aspiration (EBUS-TBNA) for Diagnostic Yield

Inclusion Criteria: * Age ≥ 18 years * Presence of enlarged mediastinal or hilar lymph nodes requiring diagnostic evaluation on chest computed tomography (CT), defined as short-axis diameter ≥ 10 mm measured on axial images * Clinical indication for EBUS-TBNA * Ability to provide written informed consent Exclusion Criteria: * Uncorrected coagulation disorders (platelet count \< 100,000/mm³; International normalized ratio (INR) \> 1.5; or prothrombin time \< 50% of control) * Acute myocardial infarction within the preceding 4 weeks or ongoing unstable angina * Significant upper airway obstruction (benign or malignant) with ≥ 50% reduction in tracheal lumen diameter * Hemodynamic instability (e.g., persistent hypotension, significant arrhythmia, or need for vasopressors) * Respiratory failure refractory to oxygen therapy, defined as sustained Peripheral oxygen saturation (SpO₂) ≤ 90% despite supplemental oxygen * Intractable cough precluding bronchoscopy * History of severe allergy to local anesthetics or sedative agents used during the procedure * Refusal or inability to provide informed consent