Abstract
Pediatric acute respiratory distress syndrome (PARDS) has an international, evidence-graded consensus guideline (PALICC-2). PALICC-2 excludes respiratory failure caused solely by airway obstruction. The Paediatric Mechanical Ventilation Consensus Conference (PEMVECC) provides general recommendations for obstructive airway disease, and the 2025 AARC/PALISI guideline on paediatric critical asthma does not address invasive ventilation. Validated, outcome-linked ventilator targets for critical asthma and a severity metric for the intubated child are still missing. This narrative review examines five possible explanations: heterogeneity of obstruction and overlap with parenchymal disease; loss of severity assessment after intubation; the small number of ventilated children; a haemodynamic hazard that develops over minutes to hours; and the brevity and instability of the illness. Adult critical care has the same gap. We pay most attention to the missing severity metric, a daily obstacle for clinicians, although solving it would not alone produce a guideline. We propose a research framework in which physiological validation and consensus development proceed in parallel. PARDS is used only as a comparator; the two conditions are distinct diseases.