BCPPS Topic 1:: Respiratory Distress Syndrome
- Dec 5, 2017
- 1 min read
Immaturity of type II alveolar cells results in endogenous surfactant deficiency. Components of endogenous surfactant. Phosphatidylcholine (70%)b. Surfactant proteins (8%).
Clinical Presentation 1. Signs and symptoms a. Tachypnea, grunting, nasal flaring, retractions, hypoxia, and cyanosis occurring soon after birth b. Chest radiograph reveals homogeneous opaque infiltrates and air bronchograms; classic “groundglass”appearance.
Male sex c. Maternal diabetes
Pharmacologic Management 1. Exogenous surfactant replacement
Other preventive and treatment strategies a. Antenatal corticosteroid i. Betamethasone 12 mg intramuscularly every 24 hours for two doses administered to women in preterm labor (between 24 and 34 weeks’ gestation) (a) Delivery should be delayed for at least 24 hours for improved response; benefit lasts up to 7 days. (b) Dexamethasone 6 mg intramuscularly every 12 hours for four doses is an alternative regimen. (c) If preterm delivery is delayed, the benefit of repeated courses is controversial. ii. Promotes fetal lung maturation and surfactant production iii. Significantly reduces mortality and incidence of RDS; effect is additive with surfactant therapy b. Inhaled nitric oxide i. Theorized role in RDS (a) Intrapulmonary shunting of blood owing to ventilation-perfusion mismatching or extrapulmonary shunting owing to pulmonary hypertension can worsen RDS. (b) Inhaled nitric oxide may improve oxygenation by vasodilating the pulmonary vasculature; thus, lowering pulmonary vascular resistance and improving distribution of pulmonary blood flow. ii. Summary of trials and meta-analysis (a) Three meta-analyses, including a Cochrane review, evaluated the use of inhaled nitric oxide in neonates with RDS. (b) No difference in mortality or incidence of BPD was shown. (c) Inhaled nitric oxide cannot be recommended for routine treatment of preterm neonates with RDS.
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