Respiratory distress syndrome of prematurity — branching viva

Branch 1 — Mechanism and recognition

The examiner opens: "Explain why this infant is in distress." A strong candidate traces surfactant deficiency through raised surface tension, alveolar collapse at end-expiration, low functional residual capacity and compliance, ventilation-perfusion mismatch with hypoxaemia and hypercapnia, and acidosis that further inhibits surfactant and constricts the pulmonary vasculature. The candidate then names expiratory grunting as auto-positive end-expiratory pressure and explains the chest radiograph triad of low volumes, granular opacities and air bronchograms. [1]

Branch 2 — Surfactant and the support ladder

The examiner pivots: "The FiO2 is now 0.35. What now?" The candidate states that the 2022 European guideline threshold of FiO2 over 0.30 on CPAP has been met, continues CPAP at 5 to 7 cm of water, and gives surfactant — poractant alfa 200 mg per kilogram — preferring the LISA or MIST technique to avoid intubation, with intubation reserved for failure of CPAP. The candidate explains that after surfactant the ventilator must be weaned promptly as compliance rises, to avoid volutrauma and air leak. [1] [2] [7]

Branch 3 — Oxygen targeting and caffeine

The examiner presses on targets: "What saturation do you aim for and why?" The candidate targets 91 to 95 percent beyond the first minutes, citing the NeOProM meta-analysis showing that the higher target reduced mortality while the lower target reduced retinopathy but increased death. The candidate adds caffeine citrate — 20 mg per kilogram loading then 5 to 10 mg per kilogram daily — citing the CAP trial for reduced apnoea and improved survival without disability. [5] [8]

Branch 4 — Complications and prevention of BPD

The examiner closes on the long view: "What are you trying to prevent?" The candidate names bronchopulmonary dysplasia, defined by oxygen or support at 36 weeks' postmenstrual age, and the acute complications of pneumothorax, pulmonary haemorrhage and intraventricular haemorrhage. The prevention bundle is antenatal corticosteroids, gentle ventilation, early surfactant, caffeine, and avoiding hyperoxia and volutrauma, with long-term follow-up for growth, neurodevelopment, audiology and retinopathy. [1]