Preoperative Gastric Ultrasound and Anaesthetic Management in Patients Undergoing Coronary Artery Bypass Grafting

Adults aged 18 years or older scheduled for elective isolated coronary artery bypass grafting at two participating centres, prepared according to routine institutional fasting practices. Participants will undergo preoperative gastric ultrasound before receiving any sedative or anaesthetic medication. Gastric contents and the anaesthetic management plans before and after disclosure of ultrasound findings will be recorded prospectively. All clinical decisions will remain at the discretion of the attending anaesthetist.

Percentage of participants with high-risk gastric contents, defined as any solid or thick gastric contents or an estimated clear fluid volume greater than 1.5 mL/kg. Clear fluid volume will be estimated using the Perlas model based on the mean of three gastric antral cross-sectional area measurements obtained in the right lateral decubitus position. An empty stomach or clear fluid volume of 1.5 mL/kg or less without solid or thick contents will be classified as low risk. Perlas grade 2 alone will not define high-risk gastric contents.

Percentage of participants with a change in surgical timing, planned anaesthetic induction technique, planned intubation approach or device, or planned aspiration precautions. The management plan recorded before gastric ultrasound will be compared with the decision and revised plan recorded immediately after the findings are disclosed to the attending anaesthetist.

Percentage of all evaluated participants whose attending anaesthetist identifies the gastric ultrasound findings as the direct reason for a change in planned anaesthetic management or surgical timing. The type of change and the clinician-reported reason will be recorded.