FACTORS AFFECTİNG ENTERAL FEEDİNG INTOLERANCE İN INTENSİVE CARE UNİT PATİENTS

Enteral nutrition is an important component of nutritional support in critically ill patients. However, enteral feeding intolerance is frequently observed in intensive care units and may result from impaired gastrointestinal motility associated with critical illness, hemodynamic instability, sedative and vasopressor use, mechanical ventilation, and underlying diseases.

In this study, demographic, clinical, laboratory, physiological, nutritional, and treatment-related variables that may affect the development of enteral feeding intolerance will be evaluated prospectively.

All adult patients admitted to the intensive care unit who are planned to receive enteral nutrition will be screened daily. Patients meeting the eligibility criteria will be enrolled after informed consent has been obtained from the patient or legally authorized representative.

Because this is an observational study, there will be no randomization and no investigator-assigned intervention. Patients will be classified according to their natural clinical course into an enteral feeding intolerance group and a non-enteral feeding intolerance group.

Demographic characteristics, admission diagnosis, APACHE II, SOFA, and Glasgow Coma Scale scores will be recorded. Daily clinical variables including bowel sounds, presence of stool, sedation, opioid use, vasopressor requirement, sepsis, and aspiration pneumonia will also be recorded.

Routine laboratory parameters including total protein, albumin, C-reactive protein, procalcitonin, lactate, hemoglobin, leukocyte count, and lymphocyte count will be obtained from the hospital electronic medical record twice weekly according to routine clinical practice.

The modified Nutrition Risk in Critically Ill (mNUTRIC) score and Prognostic Nutritional Index (PNI) will be calculated. Mechanical ventilation characteristics, enteral nutrition initiation time, formula type, daily energy and protein targets, delivered amounts, and interruptions of enteral nutrition will be recorded.

Enteral feeding intolerance will be assessed according to predefined criteria and international recommendations. The following findings will be considered enteral feeding intolerance: vomiting, a single gastric residual volume greater than 250 mL, a 24-hour gastric residual volume greater than 500 mL, abdominal distension, and suspected aspiration.

Gastric residual volume will be measured by intensive care nurses using a 50-mL syringe according to the standard intensive care unit protocol.

Intra-abdominal pressure will be measured twice weekly as part of routine intensive care practice using the Foley bladder pressure measurement technique.

All study data will be obtained from routine clinical records, laboratory results, enteral nutrition monitoring charts, ventilator records, and the hospital electronic medical record. No additional invasive procedure, imaging study, surgical procedure, or other intervention will be performed for research purposes.

Inclusion criteria

• Age ≥18 years
• Admission to the Anesthesia Intensive Care Unit
• Enteral nutrition planned or initiated during intensive care unit admission
• Expected to require enteral nutrition during intensive care unit follow-up
• Availability of sufficient clinical and nutritional data for study evaluation
• Patient or legally authorized representative provides informed consent when required by the ethics protocol

Exclusion criteria

• Age <18 years
• Patients receiving only parenteral nutrition
• Patients in whom enteral nutrition is contraindicated throughout the observation period
• Patients with insufficient data for evaluation of enteral feeding tolerance
• Patients transferred to another intensive care unit before adequate study assessment
• Patients who decline participation or whose legally authorized representative declines participation when consent is required