Surfactant Deficiency Disease



  • Surfactant deficiency disease (SDD) favored term

    • a.k.a. respiratory distress syndrome & hyaline membrane disease (archaic)

  • Common lung disease occurring in premature infants due to lack of surfactant

  • Microatelectasis & abnormal pulmonary compliance are hallmarks of disease


  • Premature infants < 32-week gestation at risk

  • Initial findings are low lung volumes & diffuse granular opacities

  • Signs of tension (lung collapse, mediastinal shift) less likely if pneumothorax develops (due to ↓ lung compliance)

  • High incidence of patent ductus arteriosus, leading to pulmonary edema (“whiteout” of lungs with cardiomegaly)

  • Bronchopulmonary dysplasia (BPD) eventually occurs in 17-55% of premature infants


  • Surfactant normally coats alveoli & ↓ surface tension, allowing alveoli to stay open

    • Prematurity-related SDD: Immature type II pneumocytes cannot produce sufficient surfactant

    • Secondary SDD: Surfactant deactivation from meconium aspiration or infection

    • Primary SDD: Dysfunctional surfactant due to abnormalities of 1 of several gene products

Clinical Issues

  • Respiratory distress, usually with history of prematurity

  • Acute complications: Alveolar rupture with barotrauma (pneumothorax, pneumomediastinum, PIE)

  • Chronic complications: BPD, ↑ incidence of sudden death

  • Treatment

    • Prenatal prevention (delay delivery, maternal steroids)

    • Surfactant administration

    • Mechanical ventilation + positive end-expiratory pressure

AP radiograph of the chest in a premature patient with surfactant deficiency disease (SDD) shows pulmonary hypoventilation & granular densities bilaterally.

AP radiograph of the chest in a premature neonate shows diffuse granular opacities with marked hyperinflation of the lungs. Although classically lung volumes are decreased in patients with SDD, artificial ventilation can make them hyperinflated, especially after surfactant administration.

AP radiograph of the chest in a 1 week old with SDD shows diffuse opacification of the lungs. This neonate's patent ductus arteriosus (PDA) had recently reversed direction due to decreasing pulmonary vascular resistance & was now causing pulmonary edema.

AP radiograph of the chest in the same patient shows increased aeration of the lungs after PDA ligation (with a surgical clip
now in place).



  • Surfactant deficiency disease (SDD) = lung disease of prematurity, respiratory distress syndrome, hyaline membrane disease (archaic)

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