Surfactant is a lipoprotein substance critical for reducing surface tension in the alveoli, preventing their collapse during expiration, and ensuring effective gas exchange.
- Production Timeline:
- Surfactant synthesis begins at 24-28 weeks of gestation in type II alveolar cells.
- Adequate levels for lung maturity are typically reached by 34-36 weeks of gestation.
- The primary phospholipid component is dipalmitoylphosphatidylcholine (DPPC), which increases significantly during this period.
- Key Components:
- Phospholipids: DPPC (most critical), phosphatidylglycerol (appears later in development).
- Proteins: Surfactant proteins (SP-A, SP-B, SP-C, and SP-D), which aid in surfactant function and immune defense.
- Regulation:
- Surfactant production is stimulated by cortisol, thyroid hormones, and beta-adrenergic agonists during late gestation.
Uses of Surfactant in Newborns
Exogenous surfactant therapy is a cornerstone in managing neonatal respiratory disorders.
- Treatment of Respiratory Distress Syndrome (RDS):
- Administered to preterm infants with immature lungs lacking sufficient surfactant.
- Prevention of RDS:
- Prophylactic use in extremely preterm infants at high risk for RDS (<30 weeks gestation).
- Management of Meconium Aspiration Syndrome (MAS):
- Helps improve oxygenation and reduce lung inflammation.
- Pulmonary Hemorrhage:
- Stabilizes alveoli and improves gas exchange after pulmonary bleeding.
- Support in Congenital Diaphragmatic Hernia (CDH):
- Enhances lung function in hypoplastic lungs.
- ARDS in Term Neonates:
- Occasionally used in severe cases caused by sepsis or pneumonia.