Does Pre-operative Gastric Ultrasound Influence Anaesthetic Decision-Making in Chronic Pain Patients? A Prospective Observational Cohort.

Inclusion Criteria: Patients were eligible for inclusion if they met all of the following criteria: * Age ≥18 years * Scheduled for elective chronic pain interventional procedures under procedural sedation * Adherence to standard preoperative fasting guidelines (≥6 hours for clear fluids and ≥8 hours for solids) * Presence of at least one clinical factor associated with delayed gastric emptying or increased risk of pulmonary aspiration, including: * Chronic opioid use (≥2 weeks) * Acute opioid administration within 24 hours prior to the procedure * Poorly controlled acute-on-chronic pain * Diabetes mellitus without established autonomic neuropathy * Symptoms of gastroesophageal reflux * Reduced functional mobility * ASA physical status II-III Exclusion Criteria: Patients will be excluded if any of the following present: * Age \<18 years * Previous gastric or esophageal surgery * Known pregnancy * Known hiatal hernia * Severe neurological disorders affecting swallowing or gastric motility * Established autonomic neuropathy affecting gastric emptying (e.g. advanced diabetic gastroparesis) * Morbid obesity (body mass index ≥35 kg·m-²), due to known limitations in gastric ultrasound image acquisition and reduced validity of volume estimation models * Inability to provide informed consent