Frequency of Metabolic Acidosis in the Pediatric Intensive Care Unit

Metabolic acidosis is one of the most common acid-base disturbances encountered in critically ill children and often reflects underlying disease severity. Despite its clinical importance, prospective epidemiological data regarding its frequency, underlying etiologies, and associated clinical outcomes among pediatric intensive care unit (PICU) admissions in Upper Egypt remain limited. The primary objective of this prospective observational cohort study is to determine the frequency of metabolic acidosis among pediatric patients admitted to the Pediatric Intensive Care Unit at Assiut University Children Hospital. Secondary objectives include identifying the common etiologies and types of metabolic acidosis, as well as evaluating its relationship with clinical outcomes such as mortality, duration of PICU stay, need for mechanical ventilation, and requirement for vasoactive support. A total of 140 eligible pediatric patients aged 1 month to 18 years admitted to the PICU will be enrolled. Eligible patients will undergo arterial blood gas (ABG) analysis and standard clinical and laboratory evaluations upon admission. Metabolic acidosis will be defined based on admission ABG criteria (serum/arterial bicarbonate \< 22 mmol/L and/or base deficit ≥ 5 mmol/L). Patients will be monitored throughout their hospital stay to assess clinical outcomes without interfering with routine medical management.

Inclusion Criteria: * Pediatric patients aged 1 month up to 18 years. * Admission to the Pediatric Intensive Care Unit (PICU). * Arterial blood gas (ABG) analysis performed on admission. Exclusion Criteria: * Neonates (age \< 1 month). * Readmission during the same hospital admission. * Patients with incomplete clinical or laboratory data. * Patients discharged or transferred before complete initial clinical and laboratory assessment