Bronchopulmonary Dysplasia (Chronic lung disease of prematurity)

Question 1

Definition

Answer 1

Chronic lung disease due to disruption of pulmonary development and injury in preterm infants

Question 2

Aetiology

Answer 2

Infants who still have an oxygen requirement at either 28 postnatal days or 36 postmenstrual weeks are described to have bronchopulmonary dysplasia (previously known as chronic lung disease of prematurity)

Lung damage is mainly thought to occur from the delay of lung maturation but can also be due to pressure and volume trauma from:

• Artificial ventilation
• Oxygen toxicity
• Infection

Question 3

Risk factors

Answer 3

Prematurity

Foetal growth restriction

Maternal smoking

Mechanical ventilation

Oxygen toxicity

Infection (antenatal and postnatal)

Inflammation

PDA

Genetics

Question 4

Presentation

Answer 4

Most frequently occurs in extremely preterm infants (< 28 weeks)

Tachypnoea

Mild-severe retractions and scattered rales (depending on the extent of pulmonary oedema or atelectasis)

Intermittent expiratory wheeze

Question 5

Investigations

Answer 5

Examination

Basic observations

CXR may show widespread areas of opacification, low/normal lung volumes, areas of atelectasis alternating with gas trapping

Cardiopulmonary function- those with more severe BPD are hypoxaemic and hypercapnic, typically needing mechanical ventilation and oxygen supplementation

Question 6

Management

Answer 6

Fluid restriction- improves pulmonary function

Respiratory Support
* Oxygen therapy- nasal cannulae or hood
* Non-invasive pressures support, CPAP
* Intubation/ ventilation if needed

Pharmacological interventions
Diuretics if on ventilator
* Thiazides
* Loop diuretics
Inhaled bronchodilators for severe BPD during acute exacerbations (NOT chronic or routine use)

Corticosteroids- used for very severe BPD and only short, low doses given

Severity

• Mild BPD (Class I) – require minimal respiratory support (low [oxygen] by nasal cannulae or hood, or non-invasive pressure support without oxygen)
• Moderate BPD (Class II) – respiratory support, not ventilator dependent, add diuretic therapy for those on PAP despite fluid restriction
• Severe BPD (Class III)- respiratory support including mechanical ventilation

Question 7

Complication/ Prognosis

Answer 7

Complications

• Systemic hypertension
• Pulmonary artery hypertension
• Neurodevelopment is poorer than unaffected babies
• Other comorbid respiratory conditions
• Ventricular hypertrophy
• Subsequent pertussis or respiratory viral infection (e.g. RSV or rhinovirus) could lead to respiratory failure, resulting in the need for intensive care

Prognosis

Most improve gradually in 2-4 months

Some infants will need prolonged ventilation, but most will be weaned onto CPAP or high-flow nasal cannulae with supplemental oxygen