Clinical scenario: Prematurity | RDS | Surfactant | Complication
A 31-week male infant weighing 1.45 kg develops progressive respiratory distress within the first hour of life. He is managed with nasal CPAP. At 12 hours of age, his oxygen requirement has increased from FiO₂ 0.25 to 0.45 despite CPAP of 7 cm H₂O.
Arterial blood gas shows:
- pH 7.26
- PaCO₂ 60 mmHg
- PaO₂ 52 mmHg
Chest radiograph demonstrates symmetrical diffuse reticulogranular infiltrates with air bronchograms.
Surfactant is administered, resulting in rapid improvement.
Two hours later, the infant suddenly deteriorates with severe desaturation and bradycardia. Examination reveals markedly reduced breath sounds over the right hemithorax, and the heart sounds are displaced to the left.
Which of the following is the most likely diagnosis?
A. Massive pulmonary hemorrhage
B. Patent ductus arteriosus
C. Right-sided tension pneumothorax
D. Severe intraventricular hemorrhage
E. Worsening respiratory distress syndrome
Correct answer & Explanation:
Correct Answer
C. Right-sided tension pneumothorax
Explanation: Surfactant / Complication
This infant initially has classical surfactant-deficient RDS.
The key to the question is the sudden deterioration after initial improvement.
Features suggesting tension pneumothorax include:
- Sudden hypoxemia
- Bradycardia
- Abrupt deterioration
- Unilateral reduction in breath sounds
- Mediastinal shift
Premature infants with RDS receiving CPAP or positive-pressure ventilation are at increased risk of air-leak syndromes, especially after surfactant when lung compliance changes rapidly.
Immediate needle thoracocentesis should be performed without waiting for radiographic confirmation if the infant is unstable.
Why the other options are incorrect
A. Massive pulmonary hemorrhage
- Usually presents with bloody secretions from the endotracheal tube and diffuse bilateral deterioration.
B. Patent ductus arteriosus
- Causes gradual worsening over days rather than sudden unilateral findings.
D. Severe intraventricular hemorrhage
- Causes neurological deterioration but does not produce unilateral absent breath sounds or mediastinal shift.
E. Worsening respiratory distress syndrome
- RDS deteriorates progressively, not with sudden unilateral chest findings.
Pearl
The most dangerous complication in a ventilated preterm infant with RDS is an air-leak syndrome.
Sudden deterioration with:
- ↓ unilateral air entry
- Bradycardia
- Desaturation
- Mediastinal shift
should be treated as tension pneumothorax until proven otherwise.
