High-Flow Nasal Oxygen During Endoscopic Retrograde Cholangiopancreatography In Geriatric Patients

Inclusion Criteria: * Age ≥18 years * Patients scheduled for elective endoscopic retrograde cholangiopancreatography (ERCP) * Planned sedation with monitored anesthesia care * ASA physical status I-III * Ability to provide written informed consent * Adult group: 18-64 years * Geriatric group: ≥65 years Exclusion Criteria: * Severe cardiac, pulmonary, renal, neurological, or hepatic disease * Baseline hypotension (systolic arterial pressure \<90 mmHg) or uncontrolled hypertension (systolic arterial pressure \>170 mmHg, diastolic pressure \>100 mmHg) * Pre-existing hypoxaemia (SpO₂ \<90%) * Known hypersensitivity to study medications or a history of sedation-related adverse events * Use of sedative medication within 24 hours prior to the procedure * Refusal to participate