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Pulmonary Interstitial Emphysema (PIE) is a form of air-leak syndrome in neonates where air escapes from alveoli into the pulmonary interstitium (perivascular and peribronchial spaces), typically due to barotrauma from mechanical ventilation.

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It is most common in preterm infants with underlying respiratory distress syndrome (RDS) receiving positive pressure ventilation.

https://youtu.be/PTrkbOs129o

Pathophysiology

Mechanism	Effect
Overdistension of fragile alveoli	Alveolar rupture
Air dissects into perivascular interstitium	Compresses adjacent alveoli and capillaries
May lead to secondary air-leak complications	Pneumothorax, pneumomediastinum, pneumopericardium

Risk factors:

Prematurity (<32 weeks gestation)
RDS (surfactant deficiency)
High-pressure mechanical ventilation (especially with high PEEP or tidal volume)
Meconium aspiration syndrome (MAS)
Surfactant therapy (transient PIE reported)

Clinical Features

Worsening or persistent respiratory distress
Hypoxemia, hypercapnia, increased ventilator requirements
Asymmetric breath sounds (if unilateral)
Sudden deterioration if complicated by pneumothorax

Pathophysiology

Clinical Features

Complications