This multicenter observational study will evaluate the association between geographic altitude, availability of critical care resources, and clinical outcomes in children with pediatric acute respiratory distress syndrome (PARDS). Data on demographics, physiology, and hospital structure will be collected from PICUs located at different altitudes worldwide. The study aims to identify gaps in PARDS management and provide recommendations adapted to diverse resource settings.

Pediatric acute respiratory distress syndrome (PARDS) is a major cause of admission and mortality in pediatric intensive care units (PICUs). In high-altitude regions, hypoxemia may be exacerbated, complicating diagnostic interpretation and clinical decision-making. At the same time, variability in the availability of advanced resources-such as mechanical ventilation modes, monitoring systems, and trained personnel-could significantly influence outcomes.

This study will prospectively and retrospectively collect clinical, physiological, and institutional data from pediatric cohorts admitted to PICUs situated at different altitudes worldwide. The analysis will explore how altitude and structural resource differences interact with oxygenation and ventilation parameters to affect patient outcomes. The ultimate goal is to generate evidence that supports context-specific guidelines, reduces inequities in critical care delivery, and strengthens pediatric intensive care practices globally.

Inclusion Criteria:

• Age between 1 month (corrected gestational age) and 18 years.
• Admission to a pediatric intensive care unit (PICU) or facility where mechanically ventilated children are cared for.
• Requirement of invasive mechanical ventilation.
• Diagnosis of pediatric acute respiratory distress syndrome (PARDS) according to PALICC criteria, confirmed within 24 hours before or after endotracheal intubation.

Exclusion Criteria:

• Patients with active perinatal lung disease (e.g., neonatal respiratory distress syndrome, pulmonary hemorrhage, persistent pulmonary hypertension of the newborn, early bronchopulmonary dysplasia, meconium aspiration).
• Patients who have received extracorporeal membrane oxygenation (ECMO) prior to or within the first 24 hours of PARDS diagnosis.
• Patients with pre-established limitation of therapeutic effort (LTE) orders or palliative care directives documented before the initiation of invasive mechanical ventilation.
• Readmissions to the PICU during the study period (only the first episode per patient will be included).

Mechanically ventilated children and adolescents (1 month-18 years) admitted to PICUs at different altitudes worldwide, who fulfill PALICC criteria for PARDS within 24 hours before or after intubation.