Hyaline Membrane Disease (Respiratory Distress Syndrome)
The most likely cause of respiratory distress in a 27-week preterm baby is hyaline membrane disease (respiratory distress syndrome) due to surfactant deficiency. 1, 2, 3
Pathophysiology at 27 Weeks Gestation
Surfactant deficiency is the primary mechanism causing respiratory distress syndrome in extremely preterm infants at 27 weeks gestation. 3 At this gestational age:
- Lung surfactant production is critically insufficient to maintain alveolar stability, leading to widespread atelectasis and impaired gas exchange 2, 3
- The alveoli collapse at end-expiration due to high surface tension, creating the characteristic "ground glass" appearance on chest radiograph 2
- High alveolar capillary permeability allows serum proteins to leak into airways, further inhibiting any residual surfactant function 2
Why Not the Other Options
Meconium aspiration syndrome (Option B) is essentially impossible in a 27-week preterm infant because meconium passage in utero is extremely rare before 34 weeks gestation—it requires mature gastrointestinal motility and is typically associated with term or post-term pregnancies. 4, 5
Transient tachypnea of the newborn (Option C) is primarily a disease of term and near-term infants delivered by cesarean section without labor, where delayed clearance of fetal lung fluid causes respiratory symptoms that typically resolve within 24-72 hours. 4, 5 While vaginal delivery (as in this case) reduces this risk, the extreme prematurity at 27 weeks makes surfactant deficiency far more likely.
Congenital heart disease (Option D) can cause respiratory distress but would not be the most likely cause in this clinical scenario of extreme prematurity with immediate post-delivery respiratory distress. 4
Clinical Evidence Supporting RDS at 27 Weeks
The evidence strongly supports RDS as the predominant diagnosis:
- Infants born at or earlier than 27 weeks gestation have the highest incidence of RDS, with 90-92% requiring surfactant therapy even when exposed to antenatal steroids 1
- At 27 weeks, the incidence of respiratory distress syndrome is not reduced after exposure to antenatal steroids, although severity may be somewhat lower 1
- Only 20-35% of infants born at 27-28 weeks gestation do NOT receive surfactant replacement, and these are typically managed successfully with CPAP alone 1
Immediate Management Priorities
This infant requires immediate respiratory support with CPAP or intubation and surfactant administration:
- Prophylactic or early rescue surfactant (within 2 hours of birth) significantly reduces mortality (RR 0.61, NNT 22), pneumothorax (RR 0.62, NNT 47), and the combined outcome of bronchopulmonary dysplasia or death (RR 0.85, NNT 24) in infants <30 weeks gestation 1
- Surfactant replacement reduces overall mortality by 47% (RR 0.53, NNT 9) in preterm infants with surfactant deficiency 1
- Early CPAP at 5-6 cm H₂O should be initiated immediately for spontaneously breathing preterm infants to prevent atelectasis by maintaining functional residual capacity 2
Critical Pitfall to Avoid
Do not delay surfactant therapy waiting for radiographic confirmation—clinical signs of respiratory distress (tachypnea, retractions, grunting, cyanosis) in a 27-week infant are sufficient to initiate treatment, as mortality increases with delayed intervention. 1 The combination of extreme prematurity and respiratory distress makes RDS the overwhelming diagnostic probability requiring immediate action.