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Air Leak & Pneumothorax

A practical guide for paediatric registrars  ·  Pneumothorax, pneumomediastinum, PIE and pneumopericardium in the newborn

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SUDDEN COLLAPSE? -
SUSPECT TENSION
PNEUMOTHORAX
📋 AIR LEAK AT A GLANCE
📖Definition
Air escaping the alveoli into extra-alveolar spaces - pneumothorax, pneumomediastinum, pulmonary interstitial emphysema (PIE) and pneumopericardium.
📊Incidence
Spontaneous pneumothorax in ~1-2% of term newborns (often asymptomatic); much higher in ventilated, RDS and MAS infants.
👶At-risk infants
Ventilated infants, RDS (especially post-surfactant), MAS, and any infant needing positive-pressure resuscitation; spontaneous in term/post-term.
⚠️Risk factors
Mechanical ventilation / high pressures, CPAP, vigorous resuscitation, RDS, MAS, meconium-stained liquor, pulmonary hypoplasia.
🔄Mechanism
High or uneven transpulmonary pressure → alveolar over-distension and rupture → air tracks into the interstitium, mediastinum and pleural space.
⏱️Onset
Often sudden - first hours to days, or during ventilation.
📈Severity
From asymptomatic to tension pneumothorax with cardiorespiratory collapse - a true emergency.
🧬 PATHOPHYSIOLOGY
1

Alveolar over-distension & rupture

High or uneven transpulmonary pressure over-distends and ruptures alveoli. The starting point of every air leak.

2

Air dissects into the interstitium (PIE)

Air tracks along the perivascular and peribronchial sheaths, giving a bubbly/streaky lung.

3

Extra-alveolar air collections

Air reaches the mediastinum (pneumomediastinum), pleural space (pneumothorax) or pericardium (pneumopericardium).

4

Tension physiology

A one-way valve lets air accumulate under pressure → lung collapse, mediastinal shift and impaired venous return.

5

Impaired gas exchange & circulation

Collapse and shift cause hypoxaemia and hypercapnia; under tension, falling cardiac output and shock.

🩺CLINICAL FINDINGS

  • Sudden deterioration: desaturation, bradycardia, hypotension (tension)
  • Increased work of breathing and cyanosis
  • Asymmetric chest movement; reduced air entry and hyper-resonance on the affected side
  • Shifted apex beat / heart sounds (mediastinal shift); distended abdomen
  • In a ventilated baby: sudden rise in oxygen/ventilation needs, falling compliance
  • Pneumomediastinum: muffled heart sounds, often less dramatic

🔬INVESTIGATIONS

  • CXR confirms: lucent hemithorax, absent lung markings, visible lung edge, mediastinal shift
  • "Spinnaker sail"/uplifted thymus in pneumomediastinum; bubbly/cystic PIE
  • Transillumination - bright on the affected side; a fast bedside aid in an unstable baby (not definitive)
  • ABG: hypoxaemia, hypercapnia
  • Continuous pre/post-ductal SpO₂
  • In peri-arrest tension, do NOT wait for a CXR - decompress clinically

🚩COMPLICATIONS & RED FLAGS

  • Tension pneumothorax → cardiorespiratory collapse (emergency)
  • Pneumopericardium → cardiac tamponade (rare, life-threatening)
  • Associated PPHN and IVH (from pressure swings)
  • Red flag: sudden desaturation + bradycardia + hypotension in a ventilated baby = tension until proven otherwise
  • Asymmetric chest with mediastinal shift - act, don't wait
🩻 CHEST X-RAY
🩻

Add a de-identified CXR here

Pneumothorax: a lucent hemithorax with absent lung markings, a visible lung edge and mediastinal shift away from the affected side (deep sulcus sign on a supine film). Pneumomediastinum lifts the thymus ("spinnaker sail" sign); PIE gives a bubbly/cystic lung. In a collapsing baby, decompress on clinical grounds - don't wait for the film.

View example films - Radiopaedia ↗ Neonatal chest signs - Radiology Assistant ↗
➕

MANAGEMENT

Match the response to the severity - observe the small and stable, decompress the symptomatic, and never delay for imaging in a tension.

Small / Asymptomatic

  • Small, asymptomatic pneumothorax in a stable, non-ventilated infant: observe with supportive care and serial monitoring
  • Most resolve spontaneously
  • High-FiO₂ "nitrogen washout" is no longer recommended (hyperoxia risk)

Symptomatic - Drainage

  • Tension/emergency: needle thoracocentesis/aspiration without waiting for imaging
  • Definitive: intercostal catheter (chest drain) to underwater seal ± suction
  • Pneumomediastinum is usually managed conservatively
  • Pneumopericardium with tamponade: emergency pericardial drainage

Prevent & Support

  • Lung-protective ventilation: lowest effective pressures, volume-targeted, permissive hypercapnia
  • HFOV for severe PIE or air leak
  • Treat underlying disease (surfactant for RDS); analgesia
  • Maintain oxygenation and perfusion; call NETS for instability or retrieval
💬 DISCUSSION QUESTIONS
1

How do you recognise and immediately manage a tension pneumothorax when there's no time for a CXR?

2

What is the role - and the limitation - of transillumination at the bedside?

3

When is a pneumothorax safe to observe versus drain?

4

How does lung-protective ventilation reduce air-leak risk?

📚 KEY GUIDELINES & EVIDENCE
ANZCOR ↗
Newborn resuscitation & stabilisation guidelines
Starship ↗
Air leak syndromes in the neonate - clinical guide
Radiopaedia ↗
Neonatal pneumothorax - imaging & signs
🔗 RESOURCES
📄LOCAL GUIDELINE 📞NETS REFERRAL
❝

Take-home message: Air leak is extra-alveolar air from alveolar over-distension and rupture - most importantly pneumothorax. Suspect a tension pneumothorax in any ventilated baby who suddenly desaturates with bradycardia and hypotension, and decompress on clinical grounds without waiting for a CXR. Small, asymptomatic leaks can be observed; symptomatic or tension leaks need needle decompression then a chest drain. Lung-protective ventilation is the best prevention.

For educational purposes only. Always align management to current ANZCOR/NRP guidelines and your local SCN/NICU or NETS protocols.

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