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
What are criteria for and timing of re-treatment with surfactant?
- Persistent or recurrent oxygen requirement of 30% or more and it may be given as early as 2h after the initial dose or more commonly 4-6h after the initial dose
How should ventilation be managed after surfactant administration?
- Options for ventilatory management after prophylactic surfactant therapy include very rapid weaning and extubation to CPAP within 1h
If we plan to give surfactant, do babies still need antenatal steroids?
- Mothers at risk of delivering babies less than 34 weeks GA should be given antenatal steroids regardless of the availability of postnatal surfactant
Should surfactant be given before transport?
- Intubated infants with RDS should get exogenous surfactant before transport
- Reduced incidence of pneumothorax is a benefit as this is a tricky complication to manage during transport
What is required of centres adminstering surfactant?
- Centres administering surfactant to newborns must ensure continuous onsite availability of personnel competent and licensed to handle acute complications of assisted ventilation and surfactant therapy
What is the most cost effective way to distribute surfactant?
- Regional networks should develop surfactant exchange programs
How should surfactant be used outside a tertiary care centre?
- Mothers with threatened preterm delivery before 32 weeks should be transferred to a tertiary care centre
- Infants delivered < 29 wks outside a tertiary centre should be considered for immediate intubation and surfactant administration after stabilization, if competent personnel are available
