Surfactant Administration for Preterm Infants with RDS
For preterm infants with RDS, administer surfactant at a dose of 100 mg/kg (beractant), 3 mL/kg (calfactant), or 2.5 mL/kg (poractant alfa) intratracheally, with the specific approach depending on gestational age and severity: initiate CPAP immediately after birth for spontaneously breathing infants <30 weeks with selective surfactant rescue if respiratory distress worsens, or provide early rescue surfactant within 1-2 hours for those requiring mechanical ventilation. 1, 2, 3
Dosing by Surfactant Type
Beractant (Survanta)
- Initial dose: 100 mg phospholipids/kg birth weight (4 mL/kg) administered intratracheally 4
- Up to 4 doses can be given in the first 48 hours, with doses administered no more frequently than every 6 hours 4
- For prevention strategy: administer first dose within 15 minutes of birth in infants with evidence of surfactant deficiency 4
- For rescue treatment: administer as soon as possible, preferably by 8 hours of age 4
Calfactant (Infasurf)
- Initial dose: 3 mL/kg birth weight administered intratracheally 5
- Can be administered every 12 hours for up to 3 total doses 5
- For infants <29 weeks gestational age at risk for RDS: administer within 30 minutes after birth 5
Poractant Alfa (Curosurf)
- Initial dose: 2.5 mL/kg birth weight (200 mg/kg phospholipids) 6
- Up to 2 repeat doses of 1.25 mL/kg may be given at approximately 12-hour intervals 6
- Maximum total dose is 5 mL/kg (initial plus repeat doses) 6
- Poractant alfa at the higher 200 mg/kg dose shows more rapid FiO2 weaning, less need for additional doses, and decreased mortality in infants <32 weeks compared to beractant 7
Treatment Strategy Based on Clinical Presentation
For Spontaneously Breathing Preterm Infants
Start with CPAP at 5-6 cm H₂O immediately after birth rather than routine intubation, as this approach with selective surfactant administration results in lower rates of BPD and death (RR 0.53,95% CI 0.34-0.83) compared to prophylactic surfactant 2, 3
- Administer selective surfactant if respiratory distress worsens despite CPAP support 1, 2
- This CPAP-first strategy has Level 1 evidence supporting its use 1, 3
For Infants Requiring Mechanical Ventilation
Preterm infants <30 weeks gestation requiring mechanical ventilation due to severe RDS should receive surfactant after initial stabilization 1, 3
- Early rescue surfactant (<2 hours of age) is superior to delayed treatment, significantly decreasing mortality (RR 0.84; 95% CI 0.74-0.95), air leak (RR 0.61; 95% CI 0.48-0.78), and chronic lung disease (RR 0.69; 95% CI 0.55-0.86) 1, 3
INSURE Technique (Intubation-Surfactant-Extubation)
The INSURE strategy significantly reduces need for mechanical ventilation (RR 0.67; 95% CI 0.57-0.79) and should be considered for appropriate candidates 3
- Intubate, administer surfactant, then rapidly extubate to nasal CPAP 2, 3
- This approach is more beneficial than continued mechanical ventilation 7
Administration Technique
Preparation
- Warm surfactant to room temperature for at least 20 minutes or in hand for at least 8 minutes before administration; do not use artificial warming 4
- Gently swirl vial to redisperse; do not shake or sonicate 4, 5, 6
- Inspect for discoloration; beractant should be off-white to light brown, calfactant and poractant alfa should be off-white 4, 5, 6
- Visible flecks and surface foaming are normal 5
Administration Methods
Traditional Endotracheal Tube Method:
- Administer through a 5 French end-hole catheter inserted into the endotracheal tube 4, 6
- For beractant: Give in 4 quarter-dose aliquots with infant positioned differently for each (head/body inclined 5-10° down with head right, then left; then inclined 5-10° up with head right, then left) 4
- For calfactant: Administer through side-port adapter as 2 equal aliquots of 1.5 mL/kg each, or through 5-French catheter as 4 equal aliquots of 0.75 mL/kg 5
- For poractant alfa: Give in 2 divided aliquots through 5 French catheter, or as single bolus through dual lumen ETT without interrupting ventilation 6
- Inject each aliquot over 2-3 seconds, then manually ventilate for at least 30 seconds or until stable 4
Less Invasive Surfactant Administration (LISA):
- Emerging evidence shows surfactant via thin catheter (without intubation) reduces death or BPD (RR 0.59,95% CI 0.48-0.73), need for intubation within 72 hours (RR 0.63,95% CI 0.54-0.74), and severe IVH (RR 0.63,95% CI 0.42-0.96) compared to traditional ETT administration 8
- This technique involves brief catheter insertion into trachea of spontaneously breathing infant on CPAP 9, 10, 8
Critical Monitoring and Adjustments
During Administration
Clinicians with expertise in intubation and ventilator management must perform or supervise surfactant administration 1, 4, 5, 6
- Monitor for transient airway obstruction, oxygen desaturation, bradycardia, and alterations in cerebral blood flow 1
- If these occur, stop administration and take appropriate measures to stabilize the infant 6
- Two attendants should be present: one to instill surfactant, another to monitor the infant 5
Post-Administration
Rapidly adjust ventilator settings after surfactant administration as lung compliance and functional residual capacity improve quickly, to minimize risk of lung injury and air leak 1
- Frequently assess oxygenation and ventilatory status 5
- Expeditious changes in FiO2 and ventilator pressures are necessary 1
Redosing Guidelines
Redosing should not be needed more frequently than every 12 hours unless surfactant is being inactivated by infection, meconium, or blood 1, 3
- The long half-life of surfactant in preterm infants with RDS supports this interval 1
- Manufacturer recommendations for shorter intervals are not based on human pharmacokinetic data 1
- Plan for up to 3 additional doses in first 48 hours if infant continues requiring mechanical ventilation with FiO2 ≥0.30 3
Special Clinical Situations
Meconium Aspiration Syndrome
Administer rescue surfactant at phospholipid dose of at least 100 mg/kg for meconium aspiration with severe respiratory failure, as this improves oxygenation and reduces ECMO need (RR 0.64; 95% CI 0.46-0.91; NNTB 6) 1, 11
Pneumonia/Sepsis
Consider rescue surfactant for infants with hypoxic respiratory failure from secondary surfactant deficiency due to pneumonia or sepsis, though evidence is limited 1, 3
- Infection can inactivate surfactant, potentially requiring more frequent redosing than the typical 12-hour interval 3
Congenital Diaphragmatic Hernia
Do not administer surfactant for congenital diaphragmatic hernia, as it has not improved outcomes and may increase need for ECMO, chronic lung disease, and mortality 1, 3
Critical Pitfalls to Avoid
- Never attempt oral surfactant administration - surfactant must be given intratracheally through an endotracheal tube or thin catheter 11
- Do not delay intubation in severe RDS requiring immediate mechanical ventilation 11
- Do not remove surfactant from refrigerator for more than 24 hours 4
- Do not warm and return to refrigerator more than once 4
- Do not filter surfactant 4
- Avoid dosing intervals shorter than manufacturer recommendations without clinical indication (active inactivation by blood, meconium, or infection) 1
- Ensure proper endotracheal tube placement and patency before administering surfactant 4, 5, 6
Synergy with Antenatal Steroids
Antenatal steroids and postnatal surfactant work independently and additively, reducing mortality, RDS severity, and air leaks more than either alone 3, 12