Serum Bicarbonate and Enteral Feeding Intolerance in Adult ICU: A Prospective Clinical Trial

Inclusion Criteria: * Adult patients aged 18 and older. * Patients started on enteral nutrition (EN) within the first 48 hours of their intensive care unit admission. * Patients predicted to remain in the intensive care unit for at least 72 hours. * Patients (or their legal representatives) who have provided consent to participate in the study. Exclusion Criteria: * Patients under the age of 18.Individuals who are currently pregnant or breastfeeding. * Patients with gastrointestinal (GI) perforation, active GI bleeding, or mechanical bowel obstruction. * Patients who have undergone major abdominal surgery (e.g., esophagectomy, gastrectomy) within the last month. * Patients receiving total parenteral nutrition (TPN) or those who are only fed orally. * Patients requiring specialized enteral formulas (e.g., diabetic, renal, immunomodulatory, elemental, or semi-elemental) due to clinical necessity. * Patients with a known diagnosis of diabetes or those with HbA1c \>6.5 requiring a diabetic enteral formula. * Patients with terminal-stage malignancy or those requiring specific enteral nutrition protocols. * Patients with advanced (Child-Pugh C) liver failure. * Patients with chronic kidney failure requiring dialysis. * Patients with diabetic ketoacidosis, severe metabolic asidozis, or those requiring initial bicarbonate replacement. * Patients who are brain dead or in the palliative care stage.