Neonatal Surfactant Therapy Flashcards
Define RDS
- Presence of acute respiratory distress with disturbed gas exchange in a preterm infant with a typical clinical course or CXR (ground glass, air bronchograms, reduced volumes)
Describe lungs of premature babies with RDS
- Anatomically and biochemically immature
- Neither synthesize nor secrete surfactant well
What is the function of surfactant?
- Lines alveolar surfaces to reduce surface tension and prevent atelectasis
What are the benefits of surfactant replacement?
- Reduced mortality
- Improve oxygenation
- Decrease incidence of air leak syndromes (pneumothorax, PIE)
- Reduced duration of ventilatory support
- Increased likelihood of survival without BPD
- Shorter hospital stays and lower costs of intensive care
- Incerased survival with no increase in adverse neurodevelopmetal outcome
Should intubated infants with RDS get surfactant?
- YES!
What other neonatal pathologies are associated with surfactant deficiency?
- MAS
- Pneumonia
- Pulmonary hemorrhage
- Albumin, meconium and blood inhibit surfactant function
What is the evidence for surfactant in MAS?
- Systematic review reported no differences in mortality or pneumothorax but decreased need for ECMO
Which MAS infants should receive surfactant?
Infants with MAS requiring > 50% FiO2
What is the evidence for surfactant use in MAS?
- Only one small controlled trial
- Possible short term physiological benefits
- No clinically significant benefits compared to a group who received restricted rescue surfactant
What is the evidence for surfactant in neonatal pneumonia?
- Small subgroup analysis of near-term babies with respiratory failure showed those with sepsis who received surfactant had a 40% decreased need for ECMO
Which infants with pneumonia should receive surfactant?
Sick newborn infants with pnuemonia + OI > 15
Which infants with pulmonary hemorrhage should receive surfactant?
Intubated newborns with pulmonary hemorrhage leading to clinical deterioration should receive exogenous surfactant
Is surfactant indicated for lung hypoplasia and CDH?
- Only small case series reported
- No conclusions can be made
What are the risks of exogenous surfactant therapy?
- Bradycardia and hypoxemia during instillation
- Blockage of endotracheal tube
- Increase in pulmonary hemorrhage (RR 1.47)
- Overdistansion and hyperventilation can happen if administered airway pressures and vent settings are not weaned
Are there any immunological changes of clinical concern associated with surfactant administration?
- Known that babies with RDS have circulating immune complexes against surfactant proteins
- Not more common in babies treated with surfactant
What is the evidence for natural surfactants being better than synthetic?
- 11 RCTs subject to systematic review
- Synthetic surfactants with overall decreased mortality (RR 0.86)
- Babies who get natural surfactants have decreased need for O2 and ventilatory support for at least 3 d compared to babies who get synthetic surfactants
- Natural surfactants improve survival without BPD and with lower incidence of airleak
What confounds the comparison of natural and synthetic surfactants?
- All studies comparing natural to synthetic surfactants used synthetic surfactants that did not contain surfactant protein analogues
- Newer synthetic surfactants containing these are currently in clinical trials
What is the evidence for prophylactic vs rescue surfactant?
- Decreased incidence of mortality, RDS, pneumothorax, PIE
- No difference in PDA, NEC, IVH
- 2 fewer deaths and 5 fewer pneumothoraces for every 100 babies treated prophylactically
- If prophylactic approach is used for all babies < 32 wks, twice as many babies will be treated compared to rescue approach
What confounds the studies comparing early vs rescue surfactant?
- Antenatal steroid use ranged from 14-50%
- Considerably less than current useage
- ? Applicability of these recommendations when ANCS approaches close to 100%?
When should surfactant be given?
- For infants at a significant risk of RDS, prophylactic natural surfactant should be given as soon as they are stable and within a few minutes after intubation
How should surfactant be given?
- In liquid form via ETT
- Slow infusion at least as effective as bolus
- Can also be given in small aliquots
- No evidence for changing position of baby during administration
What dose of surfactant should be given?
- 120mg phospholipid/1kg body weight
- Might be that lower doses can be used for prophylaxis and higher doses used for rescue
- This has not been formally studied
Who should get more than one dose of surfactant?
- Infants with RDS with presistent or recurrent O2 and ventilatory requirement within the first 72h of life
- Giving more than 3 doses not beneficial
