What are the types of surfactants used in clinical practice?

Types of Surfactants in Clinical Practice

In clinical practice, there are two main categories of surfactants used for respiratory distress syndrome (RDS): animal-derived surfactants and synthetic surfactants, with animal-derived surfactants demonstrating superior clinical outcomes for mortality and morbidity reduction. 1

Animal-Derived Surfactants

Animal-derived surfactants are modified or purified from bovine or porcine lungs and contain phospholipids along with surfactant proteins that enhance their effectiveness. These are currently the most widely used surfactants in clinical practice.

Commercially Available Animal-Derived Surfactants:

1. Beractant (Survanta)

   • Bovine-derived surfactant
   • Initial dose: 100 mg/kg
   • Contains phospholipids and surfactant-associated proteins
   • FDA-approved for rescue treatment of RDS 2

2. Poractant alfa (Curosurf)

   • Porcine-derived surfactant
   • Initial dose: 200 mg/kg (subsequent doses 100 mg/kg)
   • Indicated for rescue treatment of RDS, including reduction of mortality and pneumothoraces 3
   • Contains higher concentration of phospholipids and surfactant proteins compared to beractant

3. Calfactant (Infasurf)

   • Bovine-derived surfactant
   • Initial dose: 100 mg/kg
   • Contains surfactant-associated proteins

Clinical Advantages of Animal-Derived Surfactants:

Animal-derived surfactants have demonstrated several advantages over first-generation synthetic surfactants, including:

• Lower mortality rates (RR: 0.86; 95% CI: 0.76–0.98) 1
• Lower oxygen requirements early in the course of RDS
• Fewer pneumothoraces (RR: 0.63; 95% CI: 0.53–0.75) 1
• More rapid clinical response 4

Synthetic Surfactants

First-Generation Synthetic Surfactants:

• Colfosceril palmitate (Exosurf) - protein-free synthetic surfactant (no longer widely available)
• Pumactant - protein-free synthetic surfactant (no longer widely available)

New-Generation Synthetic Surfactants:

• Lucinactant - contains peptides that mimic surfactant protein B
• Other synthetic surfactants with protein mimics are under investigation 1

Comparative Effectiveness

Recent studies have shown some differences between available animal-derived surfactants:

• Poractant alfa (200 mg/kg initial dose) has demonstrated:

  • More rapid reduction in oxygen requirements
  • Fewer additional doses needed compared to beractant 4, 5
  • Lower mortality in infants ≤32 weeks gestation compared to both beractant and poractant alfa at 100 mg/kg dosing 4
  • Fewer days on ventilator and oxygen administration compared to beractant 6, 5

• In direct comparisons, infants treated with poractant alfa had greater rates of extubation at 48 and 72 hours compared to those treated with beractant 5

Administration Considerations

• Surfactant is typically administered through an endotracheal tube

• Administration methods include:

  • Bolus administration
  • Small aliquots
  • Infusion through an adaptor port
  • INSURE technique (INtubation-SURfactant-Extubation to CPAP)

• Timing of administration is critical:

  • Early rescue (within 1-2 hours of birth) is more effective than late rescue (>2 hours)
  • Early administration reduces mortality (RR 0.84; 95% CI 0.74–0.95) and air leaks (RR 0.61; 95% CI 0.48–0.78) 1

Clinical Pitfalls and Caveats

1. Administration complications: Surfactant administration may be complicated by transient airway obstruction, oxygen desaturation, bradycardia, and alterations in cerebral blood flow 1

2. Rapid compliance changes: Surfactant delivery can result in rapid improvement in lung compliance, requiring expeditious changes in ventilator settings to prevent lung injury 1

3. Dosing intervals: Despite some manufacturer recommendations, redosing should not be needed more often than every 12 hours unless surfactant is being inactivated by infection, meconium, or blood 1

4. Administration expertise: Clinicians with expertise in these procedures should be responsible for surfactant administration to minimize complications 1

5. Comparative efficacy: While all animal-derived surfactants are effective, some evidence suggests poractant alfa at higher initial dosing (200 mg/kg) may have advantages over beractant (100 mg/kg) in terms of ventilation requirements and mortality 4, 7, 5

Animal-derived surfactants remain the standard of care for RDS treatment, with newer synthetic surfactants with protein mimics showing promise but requiring further investigation before they can be recommended for routine clinical use.