RESPIRATORY · CHRONIC LUNG DISEASE
Chronic lung disease of prematurity
Chronic lung disease of prematurity: arrested alveolar and vascular growth after antenatal vulnerability and a postnatal hit.
WHAT IT IS
Chronic lung disease of prematurity
Bronchopulmonary dysplasia is common in the extremely preterm - reported in roughly 23-53% of babies born before 28 weeks. "Old" BPD followed oxygen toxicity and barotrauma in larger preterms; "new" BPD is a disease of arrested development - simpler, fewer, larger alveoli and a reduced microvasculature - in extremely preterm lungs that often had only mild early disease.
PATHOPHYSIOLOGY
Vulnerable lung, then a second hit
The one-line model: antenatal vulnerability + postnatal injury -> abnormal alveolar and vascular development -> pulmonary dysfunction.
IMAGING
Radiology (and why it looks different now)
| Northway stage | Findings |
|---|---|
| I | Indistinguishable from acute RDS - poor inflation, granular pattern, air bronchograms |
| II (4-10 days) | Opacification |
| III | Small diffuse cystic changes |
| IV (>1 month) | Gross architectural distortion - large cystic areas, fibrosis, atelectasis, hyperinflation |
MANAGEMENT
What actually helps
There is no single cure - the work is supportive care, nutrition and growth, while avoiding further injury. The evidence-based levers:
| Strategy | Where it sits |
|---|---|
| Caffeine | Improves BPD and neurodevelopment (CAP trial) - start early in the at-risk preterm |
| Less invasive surfactant (LISA) / early CPAP | Avoiding/limiting intubation may reduce BPD; early CPAP may reduce later wheeze and admissions |
| Vitamin A | Small reduction in BPD; modest effect, the IM regimen limits use |
| Fluid restriction / diuretics | May help selected infants with fluid-sensitive lungs |
| Bronchodilators | Only if there is airway reactivity / wheeze |
| Postnatal corticosteroids | Can aid extubation but carry neurodevelopmental risk - balance carefully; low-dose, later, selective use |
| RSV prophylaxis | Nirsevimab (or palivizumab where unavailable) before the RSV season; influenza vaccine from 6 months |
| Superoxide dismutase | Did not prevent BPD; may reduce later respiratory morbidity |
- Careful oxygen targeting (avoid hyper- and hypoxaemia); clustered, developmental cares.
- Support feeding and growth (fortification, reflux precautions); monitor weight.
- Minimise handling; watch for desaturations and signs of pulmonary hypertension.
- Family education for ongoing/home oxygen, immunisations and RSV prevention.
OUTCOMES
What follows the baby home
Severe CLD mortality is reported around 20-40%. Survivors carry recurrent respiratory infections, asthma-like symptoms and repeated hospitalisation, pulmonary hypertension, and a higher rate of neurodevelopmental difficulty - so screen for PHTN (echo) and follow growth and development closely.
KEY REFERENCES
The evidence behind the treatments
A starting point - there is a large literature around each of these. Links open the source where available.
Caffeine (CAP trial). Schmidt B, et al. Caffeine therapy for apnea of prematurity. N Engl J Med 2006;354:2112-21 [link]; long-term outcomes N Engl J Med 2007;357:1893-902 [link].
Less invasive surfactant (OPTIMIST-A). Dargaville PA, et al. Minimally invasive surfactant therapy vs sham on death or BPD. JAMA 2021;326:2478-87 [link].
Early CPAP (SUPPORT). SUPPORT Study Group. Early CPAP vs surfactant in extremely preterm infants. N Engl J Med 2010;362:1970-9 [link].
Vitamin A. Tyson JE, et al. Vitamin A supplementation for extremely-low-birth-weight infants. N Engl J Med 1999;340:1962-8 [link].
Postnatal corticosteroids. Doyle LW, et al (DART). Low-dose dexamethasone to facilitate extubation. Pediatrics 2006;117:75-83. See also the Cochrane reviews of early vs late systemic corticosteroids (Doyle, 2021).
Early low-dose hydrocortisone (PREMILOC). Baud O, et al. Survival without BPD in extremely preterm infants. Lancet 2016;387:1827-36 [link].
RSV prophylaxis - nirsevimab (MELODY). Hammitt LL, et al. Nirsevimab for prevention of RSV in late-preterm and term infants. N Engl J Med 2022;386:837-46 [link]. Palivizumab: IMpact-RSV Study Group, Pediatrics 1998;102:531-7.
Diuretics & bronchodilators. Cochrane systematic reviews support selective, symptom-driven use rather than routine therapy.
Superoxide dismutase. Davis JM, et al. Pulmonary outcome at 1 year in preterm infants. Pediatrics 2003;111:469-76.
Definition & history. Jensen EA, et al. The diagnosis of BPD in very preterm infants: an evidence-based approach. Am J Respir Crit Care Med 2019;200:751-9 [link]. Original description: Northway WH, et al. N Engl J Med 1967;276:357-68.
BPD in one line: arrested alveolar and vascular development after antenatal and postnatal injury. Caffeine, gentle/non-invasive support and nutrition are the mainstays; steroids are a careful trade-off; and don't forget the pulmonary hypertension and the RSV jab.
Educational summary for clinical teaching. Definitions and steroid regimens vary - follow current local neonatal guidelines.