Bronchopulmonary Dysplasia

1. Definition
   1. Chronic Lung Disease in Infants and Children
   2. Occurs secondary to Hyaline Membrane Disease associated with Prematurity
2. Epidemiology
   1. Incidence increases with earlier gestational ages
   2. Incidence increases with lower birth weights
      1. Incidence: Affects 50-80% of infants with birth weight <900 grams
      2. Incidence has dramatically decreased with the regular use of surfactant in premature infants
3. Pathophysiology
   1. Chronic lung inflammation and scarring related to prolonged Mechanical Ventilation in premature infants
   2. Reults in lung remodeling
4. Risk Factors
   1. Very low birth weight
   2. Meconium Aspiration
   3. Congenital Heart Disease (e.g. Patent Ductus Arteriosus)
   4. Perinatal infections (e.g. TORCH Viruses)
   5. Persistent Pulmonary Hypertension
   6. Significant levels of Ventilatory support
5. Signs
   1. Tachypnea
   2. Wheezing
   3. Increased work of breathing
   4. Harrison Groove
      1. Thoracic depression at the lower aspect of the chest (at diaphragm insertion)
      2. Results in pear-shaped chest appearance
6. Diagnosis: Criteria (all 3 required)
   1. Mechanical Ventilation in the neonatal period
   2. Continued oxygen needs at age 28 days
   3. Respiratory insufficiency
7. Imaging: Chest XRay
   1. Stage 1 (Days 1 to 3)
      1. Findings similar to respiratory distress syndrome of the newborn
   2. Stage 2 (Days 4 to 10)
      1. Radiopacity markedly increased
   3. Stage 3 (Days 10-20)
      1. Cystic pattern
   4. Stage 4 (Days >28)
      1. Hyperexpansion
      2. Cardiomegaly may be present
      3. Emphysematous areas
8. Management: Exacerbations and general concerns
   1. Treat as Asthma Exacerbation initially
      1. See Pediatric Asthma
      2. Recognize that some obstruction may be fixed and unresponsive to further bronchodilation
         1. Trial Bronchodilators but do not over-use if poor response
      3. Supportive care may be mainstay of therapy (oxygen, IV hydration)
   2. Oxygen
      1. Keep Oxygen Saturation at 92% or higher
      2. Home oxygen may be required
   3. Inhaled agents
      1. Albuterol
      2. Ipratropium Bromide
      3. Inhaled Corticosteroids (e.g. Budesonide or Fluticasone)
   4. Adjunctive agents
      1. Diuretic indications
         1. Consider in sudden weight gain
      2. Antibiotics indications
         1. Immunodeficiency
         2. Recurrent respiratory infections
         3. Suspected bacterial illness
   5. Car Seats may need adjustment (restraint may exacerbate symptoms)
      1. Require Car Seat test before NICU discharge
      2. Special prone or supine car safety device may be indicated
9. Management: Hospital admission indications
   1. Respiratory Rate >70-80 per minute (or significant increase from baseline)
   2. Hypoxia with increased oxygen requirement (or hypercarbia)
   3. Poor feeding secondary to respiratory condition
   4. Apnea
   5. New Pulmonary Infiltrates
10. Complications
    1. Heart and lung changes
       1. Cor Pulmonale (or Pulmonary Hypertension)
       2. Right Ventricular Hypertrophy (and main pulmonary artery enlargement)
    2. Apparent Life-Threatening Events In Children (ALTE)
    3. Respiratory infections (e.g. RSV)
       1. Increased susceptibility
       2. Increased severity
    4. Reactive Airways
       1. Episodic respiratory distress and Wheezing
    5. Growth Delay
       1. Require higher caloric intakes due to increased work of breathing
11. Associated Conditions: Exacerbating factors seen in very premature infants
    1. Subglottic Stenosis (from prolonged intubation)
    2. Laryngomalacia
    3. Tracheomalacia
12. Course
    1. Lung function often normalizes by teen years
13. References
    1. Claudius and Boyer in Majoewsky (2013) EM:Rap 13(2):10
    2. Fuchs and Yamamoto (2011) APLS, Jones and Bartlett, Burlington, p, 72-5
    3. Walsh (2006) Pediatrics 117: S52-6