Neonatal respiratory Distress Syndrome(NRDS) Tongji Hospital L
Neonatal Respiratory Distress Syndrome (NRDS) Tongji Hospital
Neonatal Respiratory Distress Syndrome(RDs or: Hyaline Membrane Disease(HMD) Most common cause of respiratory failure in the first days Occurring in 1-2%o of newborn infants(GA 26-28W, 50% 30-3lw, less than 20-25%) Mortality 50%at 20 yrs ago, Survive 80-90%now High risk: IDM, GA<37w, multi preg, C-Section, asphyxia, cold stress, history of prior affected, male or white infants Low risk: chronic or pregnancy-associated hypertension, maternal opiate addiction, PROM, antenatal corticosteroid
Neonatal Respiratory Distress Syndrome (NRDS) or: Hyaline Membrane Disease (HMD) ➢ Most common cause of respiratory failure in the first days ➢ Occurring in 1~2% of newborn infants (GA 26~28w, 50%, 30~31w, less than 20~25%) ➢ Mortality ~50% at 20 yrs ago, Survive 80~90% now ➢ High risk: IDM, GA<37w, multi preg., C-section, asphyxia, cold stress, history of prior affected, male or white infants ➢ Low risk: chronic or pregnancy-associated hypertension, maternal opiate addiction, PROM, antenatal corticosteroid
Lung Development s Embryonic Lung development G Fetal lung Development (Pseudoglandular, Canalicular, Terminal Saccular) Postnatal Lung Development
Lung Development Embryonic Lung Development Fetal Lung Development (Pseudoglandular, Canalicular, Terminal Saccular) Postnatal Lung Development
Embryonic lung development Primary bronchial Esophagus primitive lung main bronchi Bronchial buds Blood vessel Mesoderm 26-28 days 26-28 days Primary bron Trachea lobar bronchi Mesenchyme econdary(loban) enchyma Secondary (lobar bronch bronchus 4-5 weeks Esophagus Blood vesse pRimary bronchi Lobar bronch segmental bronchi Tertiary (segmental Lobar bronchus Primary bronchus
Embryonic Lung Development primitive lung main bronchi lobar bronchi segmental bronchi
Fetal Lung Development Pseudoglandular stage x7th-16th week Right primary bronc Left primary bronchus Myofibroblasts buds bronch 8的 Acuna bronchi Subsegmental bronchi G 7- 16 weeks Primitive bronchial tree Terminal bronchioles
Fetal Lung Development Pseudoglandular Stage ~ 7th – 16th week Primitive bronchial tree Terminal bronchioles
Fetal Lung Development Canalicular Stage 16 n-24 week Terminal Saccular Stage -24th-36th week Intersaccular septa Squamous epithelium Transitory ducts Artery Terminal buds Myofibroblasts Myofibroblast R Columna epithelium Capillaries Terminal bronchiole Respiratory bronchiole Diated acinar tubules Respiratory bronchiole Transitory saccules 16-24 weeks 24-36 weeks Respiratory bronchioles Transitory saccules and ducts
Fetal Lung Development Canalicular Stage ~ 16th – 24th week Terminal Saccular Stage ~ 24th – 36th week Respiratory bronchioles Transitory saccules and ducts
Postnatal Lung Development Postnatal Development birth-8 year Alveolar period Primary Alveolar Septa Pnmary alveoar septa 3 Alveolar duct Myot:broblasts 'SWE ansitory ducts Terminal bronc Terminal Respiratory bronchiole Respiratory bronchiole Alveoli Capil c 36 weeks D Postnatal Secondary alveolar septa Alveolar ducts and alveoli
Postnatal Lung Development Postnatal Development ~ birth – 8 year Alveolar period Secondary alveolar septa Alveolar ducts and alveoli
Surfactant start synthesis in 20-24w o· docto increase in 28-32w J八∧ meet demands after 35w bodle body Y double in alveolar within 24h Type I ca adult level after 3-7d s- TyPe l Cell √haf-life12~24h Blood v renew in 24-48, >90% reuse Type I Cell
Surfactant ✓start synthesis in 20~24w ✓increase in 28~32w ✓meet demands after 35w ✓double in alveolar within 24h ✓adult level after 3~7d ✓half-life 12~24h ✓renew in 24~48,>90% reuse
Surfactant Composition Phospholipid 90%(neutral 5%) saturated 50% unsaturated 35 Protein 10%(albumin 5%) SP-A, 30-35kDa, 18 ologomer, hydrophilic D 43kDa, 12 oligomer SP-B kdA, dimer, hydrophobic kdA dimer
Surfactant Composition • Phospholipid 90% (neutral 5%) saturated 50％ unsaturated 35％ • Protein 10％ (albumin 5%) SP-A, 30~35kDa, 18 ologomer, hydrophilic D, 43kDa, 12 oligomer SP-B, 8kDa, dimer, hydrophobic C, 4kDa, dimer
Function of Pulmonary Surfactant Decrease alveolar surface tension, reduce respiratory work Maintain alveoli inflation and functional residual capacity Accelerate lung fluid absorption, reduce alveolar effusion Pathogen Opsonization, alveolar macrophage activation Effects: improve oxygenation, ameliorate ventilation/perfusion anti-inflammation Fluid surface tension Pressure(P) 2xSurface tension(y) radius (r
Function of Pulmonary Surfactant • Decrease alveolar surface tension, reduce respiratory work • Maintain alveoli inflation and functional residual capacity • Accelerate lung fluid absorption, reduce alveolar effusion • Pathogen Opsonization, alveolar macrophage activation Effects: improve oxygenation, ameliorate ventilation/perfusion anti-inflammation Fluid surface tension Pressure (P) = 2xsurface tension() radius (r)