RDS and Surfactant Therapy RDS Improvements in outcome

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RDS and Surfactant Therapy

RDS and Surfactant Therapy

RDS Improvements in outcome due to: l Antenatal steroids l Early postnatal surfactant therapy

RDS Improvements in outcome due to: l Antenatal steroids l Early postnatal surfactant therapy l Gentler ventilation techniques 2

Risk Factors l Prematurity l Males l Second born twins l Infants born by

Risk Factors l Prematurity l Males l Second born twins l Infants born by c-section l Caucasian race l Maternal diabetes l Asphyxia 3

Sequelae of RDS l Intraventricular hemorrhage l Periventricular leukomalacia l Bronchopulmonary dysplasia l Patent

Sequelae of RDS l Intraventricular hemorrhage l Periventricular leukomalacia l Bronchopulmonary dysplasia l Patent ductus arteriosus l Pulmonary hemorrhage 4

Decreased Incidence of RDS l Use of antenatal steroids l Pregnancy-induced or chronic maternal

Decreased Incidence of RDS l Use of antenatal steroids l Pregnancy-induced or chronic maternal hypertension l Prolonged rupture of membranes l Maternal narcotic addiction 5

Secondary Surfactant Deficiency l Intrapartum asphyxia l Pulmonary infections l Pulmonary hemorrhage l Meconium

Secondary Surfactant Deficiency l Intrapartum asphyxia l Pulmonary infections l Pulmonary hemorrhage l Meconium aspiration syndrome l Oxygen toxicity/barotrauma/volutrauma 6

Role of Surface Tension in Pulmonary Function l Surfactant reduces surface tension at air-fluid

Role of Surface Tension in Pulmonary Function l Surfactant reduces surface tension at air-fluid interface l Improves lung compliance l La. Place equation P = 2 T r l Contains hydrophobic groups (tails) and hydrophilic groups(heads) and forms monolayer 7

Compliance Maximal volume Volume Pressure Opening pressures 8

Compliance Maximal volume Volume Pressure Opening pressures 8

Surfactant Deficiency l Surfactant deficiency = decreased compliance l Decreased compliance = alveolar collapse

Surfactant Deficiency l Surfactant deficiency = decreased compliance l Decreased compliance = alveolar collapse and loss of FRC l Loss of FRC = V/Q mismatch l V/Q mismatch = desaturation, and respiratory distress 9

Composition of Pulmonary Surfactant 10

Composition of Pulmonary Surfactant 10

Surfactant Metabolism Lamellar bodies Synthesis Secretion Alveoli Recycling Clearance 11

Surfactant Metabolism Lamellar bodies Synthesis Secretion Alveoli Recycling Clearance 11

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Antenatal Steroids Decrease RDS Gest. age Rate of RDS without steroids Rate of RDS

Antenatal Steroids Decrease RDS Gest. age Rate of RDS without steroids Rate of RDS with Steroids <30 weeks 60% 35% 30 -34 weeks 25% 10% >34 weeks 5% 5% 13

Effects of Corticosteroids on Surfactant Synthesis l Increase surfactant phospholipids l Increase CP-cytidyltransferase activity

Effects of Corticosteroids on Surfactant Synthesis l Increase surfactant phospholipids l Increase CP-cytidyltransferase activity l Increase fatty-acid synthase activity l Increase surfactant proteins gene expression l Induce ion and water transport proteins 14

Surfactant Therapy for RDS Significant reduction in: l Mortality l Pneumothorax Unaltered: l Bronchopulmonary

Surfactant Therapy for RDS Significant reduction in: l Mortality l Pneumothorax Unaltered: l Bronchopulmonary dysplasia l Intraventricular hemorrhage l Sepsis l Patent ductus arteriosus 15

Surfactant Therapy for RDS Decreases mortality l Greatest benefit when used with antenatal steroids

Surfactant Therapy for RDS Decreases mortality l Greatest benefit when used with antenatal steroids l Improvement in compliance, functional residual capacity, and oxygenation l Reduces incidence of air leaks l 16

Surfactant Therapy For RDS l Natural protein-containing preparations show a faster therapeutic response l

Surfactant Therapy For RDS l Natural protein-containing preparations show a faster therapeutic response l Major surface lowering component: phosphatidylcholine l Retreatment mostly required in severe RDS 17

Surfactant Replacement Therapy l Administer less than 2 hours after birth l Consider delivery

Surfactant Replacement Therapy l Administer less than 2 hours after birth l Consider delivery room use in infants < 1000 grams l Most infants require 2 doses 18

RDS-clinically Non-specific findings of respiratory distress: • Grunting • Flaring • Retracting • O

RDS-clinically Non-specific findings of respiratory distress: • Grunting • Flaring • Retracting • O 2 requirement 19

RDS-radiography • Diffuse reticular granular or • “ground glass”pattern • Air bronchograms • Underaeration

RDS-radiography • Diffuse reticular granular or • “ground glass”pattern • Air bronchograms • Underaeration 20

Mild RDS 21

Mild RDS 21

Moderate RDS 22

Moderate RDS 22

Severe RDS 23

Severe RDS 23

Pulmonary Interstitial Emphysema 24

Pulmonary Interstitial Emphysema 24

Pneumothorax 25

Pneumothorax 25

Treatment l Surfactant administration if intubation required. l CPAP to prevent atelectasis l CPAP

Treatment l Surfactant administration if intubation required. l CPAP to prevent atelectasis l CPAP as adjunct following surfactant administration l Blood gases: p. H of 7. 25 -7. 4 PCO 2 of 40 -65 mm Hg Pa. O 2 of 50 -70 mm Hg 26