This prospective observational study aims to evaluate dynamic changes in gastric volume and gastric emptying time using bedside gastric ultrasound in mechanically ventilated intensive care unit patients. The study compares gastric emptying patterns among patients receiving different types of enteral nutrition solutions as part of routine clinical care.

This prospective observational study is designed to evaluate gastric emptying and changes in gastric volume using bedside gastric ultrasound in mechanically ventilated intensive care unit patients. Ultrasound examinations will be performed at predefined time points to assess gastric residual volume and gastric emptying patterns.

Patients receiving different types of enteral nutrition solutions as part of routine clinical care will be evaluated and compared. Gastric measurements will be obtained using standardized ultrasound techniques by trained clinicians.

The study aims to identify differences in gastric emptying dynamics associated with various enteral nutrition formulations and to assess the feasibility of bedside ultrasound as a non-invasive tool for monitoring gastric function in critically ill patients.

Inclusion Criteria:

• Age 18 years or older
• Mechanically ventilated patients admitted to the intensive care unit
• Presence of a nasogastric tube
• Hemodynamically stable patients receiving enteral nutrition as part of routine clinical care

Exclusion Criteria:

• Recent abdominal surgery within the first 24 hours
• Major abdominal trauma or burns
• Significant ascites
• Inadequate ultrasound window (e.g., severe meteorism)
• Hemodynamic instability
• Contraindication to enteral nutrition

The study population consists of adult patients aged 18 years and older who are mechanically ventilated and admitted to the intensive care unit. Eligible patients are those receiving enteral nutrition via a nasogastric tube as part of routine clinical care and who are hemodynamically stable. Patients will be observed prospectively without any protocol-driven intervention.

Individual participant data will not be shared due to institutional data protection policies and the inclusion of critically ill patients. Data will be analyzed and reported in an aggregated and anonymized manner.