Pulmonary Surfactant Flashcards
What is Surfactant?
a surface-active lipoprotein complex formed by the type II alveolar cells; it lines the alveoli and the smallest bronchioles
which type of cells form surfactant?
Type II alveolar cells
How is surfactanct produced?
Begins in the Type II cells during the terminal sac stage of lung development (17-26 weeks); lamellar bodies appear in the cytoplasm at about 20 weeks gestation; term infants are estimated to have an alveolar storage poo off approx 100mg/kg of surfactant; preterm infants have only 4-5 ml/kg at birth
When is the terminal sac development?
17-26 weeks
how does surfactant work?
increases pulmonary compliance; reduces surface tension; faclitates recruitment of collapsed airways; protects the pumonary epithelium; prevents atelectasis at the end of expiration
Alveolar size
as the alveoli increases in size, the surfactant becomes distributed and helps all alveoli in the lungs to expand at the same rate
Keeping the airways dry
surface tension forces also draw fluid from the capillaries to the alveolar spaces; by reducing the surface tension, the fluid from the capillaries is not drawn into the alveolar spaces
composition
~40% DPPC; ~40% phospholipids; ~ 5% surfactant associated proteins (P A,B,C,D); cholesterol (neutral lipids); traces of other substances
Diseases r/t surfactant deficiency
RDS, congenital surfactant deficiency; pulmonary alveolar proteinosis
Types of surfactants:
Synthetic: Exosurf
Animal derived: curosurt-pork
Infasurf-calf lung
Survanta- cow ling with DPPC, palmitic acid and tripalmitin
Dosage and administration
depends on type given
Monitoring:
ET patency and position; O2 sats, EKG, b/p, watch for post-dose hyperoxia; Blocked airway
Adverse effects/precautions
reflux, o2 desat, pulmonary hemorrhage; postdose hyperoxia, hypocarbia and or overventilation possible resulting in a pneumo
