Maternal diabetes mellitus: leads to ↑ fetal insulin, which inhibits surfactant synthesis
Hereditary
Cesarean delivery: results in lower levels of fetal glucocorticoids than vaginal delivery, in which higher levels are released as a response to stress from uterine contractions
Hydrops fetalis
Multifetal pregnancies
Male sex
Pathophysiology
Surfactant deficiency
Little or no reduction of alveolar surface tension → increased alveolar collapse → atelectasis → decreased lung compliance and functional residual capacity → hypoxemia and hypercapnia
Clinical features
Maternal history of premature birth
Onset of symptoms: usually immediately after birth but can occur up to 72 hours postpartum
Signs of increased respiratory effort
Tachypnea
Nasal flaring and moderate to severe subcostal/intercostal and jugular retractions
Characteristic expiratory grunting
Decreased breath sounds on auscultation
Cyanosis due to pulmonary hypoxic vasoconstriction
Diagnostics
X-ray chest
Interstitial pulmonary edema with perihilar streaking
Diffuse, fine, reticulogranular (ground-glass) densities with low lung volumes and air bronchograms
Atelectasis
Complications
Bronchopulmonary dysplasia (BPD)
Definition: chronic lung condition secondary to prolonged mechanical ventilation and oxygen therapy for NRDS
Etiology: Pulmonary barotrauma and oxygen toxicity with subsequent inflammation of lung tissue due to ventilation of the immature lung (ventilation for more than 28 days)
Clinical features
Seen in infants < 32 weeks
Persistence of symptoms similar to NRDS (e.g., tachypnea, grunting, nasal flaring)
Episodes of desaturation
Diagnostics
X-ray chest: diffuse, fine, granular densities, areas of atelectasis interspersed with areas of hyperinflation
Blood gas analysis: respiratory and metabolic acidosis
Histology: atelectasis, fibrosis, emphysematous alveolar changes (decreased number and septation of alveoli)
