Overview
Definition:
Pneumothorax in neonates is the presence of air in the pleural space, leading to partial or complete collapse of the lung
It is a potentially life-threatening condition requiring prompt recognition and management.
Epidemiology:
Incidence varies but is estimated to be between 0.1% to 1% of all neonates, with higher rates in premature infants, those with respiratory distress syndrome (RDS), meconium aspiration syndrome, and those requiring positive pressure ventilation.
Clinical Significance:
Neonatal pneumothorax can rapidly lead to severe hypoxemia, hypercapnia, and hemodynamic compromise due to impaired venous return and reduced cardiac output
Early diagnosis and intervention are critical for survival.
Clinical Presentation
Symptoms:
Sudden onset of tachypnea
Grunting respirations
Cyanosis
Decreased breath sounds on the affected side
Nasal flaring and retractions
Apnea spells
Bradycardia or tachycardia
Hypotension
Diminished or absent unilateral chest movement.
Signs:
Audible air leak
Hyperresonance to percussion on the affected side
Tracheal deviation away from the affected side in tension pneumothorax
Absent or diminished unilateral breath sounds.
Diagnostic Criteria:
Clinical suspicion based on risk factors and presentation
Confirmed by chest X-ray showing visceral pleural line with absence of lung markings peripherally
Ultrasound can also be diagnostic.
Diagnostic Approach
History Taking:
Focus on gestational age, mode of delivery, antenatal history
History of respiratory distress, mechanical ventilation, resuscitation, any underlying lung disease (RDS, MAS)
Recent procedures like umbilical catheterization or chest tube insertion.
Physical Examination:
Systematic assessment of respiratory rate, effort, and oxygenation
Auscultate for breath sounds, noting symmetry and presence of adventitious sounds
Palpate for chest wall movement and percussion notes
Assess for signs of shock.
Investigations:
Chest X-ray (anteroposterior and lateral views) is the gold standard for diagnosis
It reveals air in the pleural space and lung collapse
A portable X-ray may be necessary for unstable infants
Ultrasound can be a rapid bedside tool.
Differential Diagnosis:
Congenital cystic adenomatoid malformation (CCAM)
Bronchopulmonary sequestration
Diaphragmatic hernia
Lobar emphysema
Pulmonary interstitial emphysema
Congenital heart disease.
Transillumination
Procedure:
A bright light source (e.g., fiberoptic transilluminator) is placed on the chest wall, typically in the anterior axillary line or above the nipple
Normal lung tissue transmits light dimly
A pneumothorax will appear as a brightly illuminated area due to air in the pleural space.
Interpretation:
A brightly transilluminating area over the lung field strongly suggests the presence of air or fluid in the pleural space
It is most useful in differentiating a pneumothorax from other causes of unilateral lung pathology, especially at the bedside.
Limitations:
Sensitivity can be reduced in obese infants or those with significant subcutaneous air
It is less reliable for small pneumothoraces or loculated air
It does not quantify the size of the pneumothorax.
Needle Decompression
Indications:
Tension pneumothorax causing hemodynamic instability (hypotension, severe hypoxemia, bradycardia)
Neonates with a confirmed large pneumothorax that is causing significant respiratory compromise and cannot be immediately managed with a chest tube.
Procedure:
A 23-25 gauge needle or small angiocatheter is inserted through the chest wall into the pleural space, usually in the second intercostal space in the midclavicular line or the anterior axillary line
The needle is advanced, and air is aspirated
Aspiration of air confirms entry into the pleural space.
Technique:
Use sterile technique
Insert the needle perpendicular to the chest wall
Aspirate slowly
If air returns, the needle is in the pleural space
Release the pressure
This is a temporizing measure until definitive chest tube placement.
Complications:
Injury to lung parenchyma, intercostal vessels or nerves, diaphragm, liver, or spleen
Hemothorax or chylothorax
Infusion of air into subcutaneous tissue
Failure to decompress due to incorrect placement or loculated air.
Management
Initial Management:
Secure airway, provide supplemental oxygen, and assist ventilation if necessary
Stabilize hemodynamics
If tension pneumothorax is suspected, immediate needle decompression is indicated.
Chest Tube Thoracostomy:
This is the definitive treatment for most significant pneumothoraces
A chest tube is inserted into the pleural space and connected to an underwater seal drainage system
The size of the tube depends on the infant's weight.
Supportive Care:
Continuous cardiorespiratory monitoring
Serial chest X-rays to assess lung re-expansion and tube function
Management of underlying causes of pneumothorax
Pain management
Nutritional support.
Key Points
Exam Focus:
Recognize risk factors for neonatal pneumothorax
Understand the rapid deterioration associated with tension pneumothorax
Differentiate transillumination findings
Know indications and immediate steps for needle decompression
Chest tube thoracostomy is definitive management.
Clinical Pearls:
Always consider pneumothorax in a neonate with sudden respiratory decompensation, especially if on positive pressure ventilation
Transillumination is a quick bedside test
Needle decompression is a life-saving temporizing measure
Prompt chest tube insertion is crucial.
Common Mistakes:
Delaying diagnosis due to atypical presentation
Confusing pneumothorax with other causes of respiratory distress
Inadequate oxygenation and ventilation support
Mistaking a lung cyst for a pneumothorax on X-ray
Incorrect placement of needle for decompression.