Pulmonary Surfactants
Key Points
- Pulmonary surfactant is a phospholipid secreted by type-II alveolar cells that reduces surface tension in the lungs, preventing alveolar collapse during exhalation.
- Preterm infants (<32 weeks’ gestation) do not produce adequate surfactant, resulting in respiratory distress syndrome (RDS).
- Exogenous surfactant (beractant/Survanta) is collected from animal lungs and administered via endotracheal tube to preterm infants.
- Dose: 4 mL/kg (100 mg phospholipids/kg) administered in four 1 mL/kg aliquots; up to 4 doses in first 48 hours, no more frequently than every 6 hours.
- Monitor for oxygen desaturation and transient bradycardia during administration; withhold suctioning for 1 hour after each dose unless airway obstruction occurs.
Pathophysiology of Surfactant Deficiency
Pulmonary surfactant is a surface-active phospholipid produced by alveolar type-II (AT-II) epithelial cells. Its function is to decrease surface tension at the gas-liquid interface of the alveoli, preventing collapse during exhalation.
Development timeline: Lung-surfactant production begins at approximately 24 weeks’ gestation, but adequate amounts are not produced until at least 32 weeks’ gestation.
In preterm infants, surfactant deficiency causes:
- Alveolar collapse with each breath (atelectasis)
- Increased work of breathing — the infant must generate extreme pressure to reinflate collapsed alveoli
- Progressive hypoxia and hypercapnia
- Respiratory failure if untreated
Respiratory Distress Syndrome (RDS)
RDS (formerly called hyaline membrane disease) is the primary indication for surfactant therapy:
| Feature | Details |
|---|---|
| Population | Preterm infants; higher risk with lower gestational age; white males in late preterm also at risk |
| Signs | Tachypnea, nasal flaring, expiratory grunting, multilevel retractions, cyanosis |
| Chest X-ray | Low lung volumes, diffuse reticulogranular “ground glass” pattern, air bronchograms |
| Course | Worsens over first 2–3 days; improves as endogenous surfactant production begins |
Drug: Beractant (Survanta)
Drug class: Exogenous pulmonary surfactant (bovine-derived)
Mechanism: Provides exogenous phospholipids to replace deficient surfactant, reducing alveolar surface tension and restoring functional residual capacity.
Indications:
- Prevention and treatment of RDS in premature neonates
- Lung immaturity in neonates at risk for RDS
Dosing
| Parameter | Details |
|---|---|
| Dose | 4 mL/kg (100 mg phospholipids/kg) |
| First dose | As soon as possible after birth — preferably within 15 minutes |
| Frequency | Up to 4 doses within the first 48 hours of life; no more frequently than every 6 hours |
| Maximum | Usually requires no more than every 12 hours unless surfactant is being inactivated by infection |
Administration Technique
ETT Required
Beractant is administered exclusively via endotracheal tube. The infant must be intubated and stable prior to administration.
- Confirm infant is stable before proceeding
- Insert a 5 French end-hole catheter into the endotracheal tube
- Administer dose in four 1 mL/kg aliquots (quarter-doses)
- Each quarter-dose instilled over 2–3 seconds, followed by ≥30 seconds of manual ventilation or until infant is stable
- Each quarter-dose administered in a different position:
- Slightly downward with head turned right
- Slightly downward with head turned left
- Slightly upward with head turned right
- Slightly upward with head turned left
- Withhold suctioning for 1 hour after full dose — unless signs of significant airway obstruction occur
Nursing Assessment
NCLEX Focus
Surfactant is administered via ETT — nurses must monitor O₂ saturation and heart rate closely during each aliquot. Withhold suctioning for 1 hour post-dose. Improvement in oxygenation after surfactant = expected response, not a complication.
- Assess infant’s respiratory status before and throughout administration: SpO₂, heart rate, breath sounds, work of breathing
- Assess ventilator settings — as oxygenation improves after surfactant, ventilator support may need to be weaned
- Monitor for diuresis — may occur as oxygenation improves
- Confirm correct ETT placement before each dose
Adverse Effects and Monitoring
| Effect | Timing | Nursing Action |
|---|---|---|
| Oxygen desaturation | During instillation | Pause, ventilate manually until stabilized |
| Transient bradycardia | During instillation | Pause, assess, ventilate; notify provider if persistent |
| Blood pressure alterations | During/after dose | Continuous monitoring; report significant changes |
| Pulmonary hemorrhage | Rare, severe | Emergent respiratory support; notify provider immediately |
| Patent ductus arteriosus (PDA) | Post-treatment | Assess for bounding pulse, murmur; echocardiogram if suspected |
Nursing Interventions
- Warm refrigerated vial to room temperature by holding in hands for at least 8 minutes — do NOT microwave or shake
- Confirm ETT patency and position before administration
- Position infant per administration protocol (four positional aliquots)
- Monitor SpO₂ and heart rate continuously during administration — pause and ventilate if desaturation or bradycardia occurs
- Withhold airway suctioning for 1 hour after dose unless obstruction occurs
- Anticipate progressive improvement in oxygen requirements — wean supplemental oxygen and ventilator support as directed as oxygenation improves
- Educate parents: explain that the infant is receiving surfactant to replace what the premature lungs cannot yet produce on their own
Related Concepts
- preterm-newborn — RDS is the primary respiratory complication of prematurity; surfactant therapy is the core treatment.
- newborn-resuscitation — Surfactant is given in the context of immediate neonatal stabilization for respiratory failure.
- acute-respiratory-distress-syndrome — Surfactant deficiency causes RDS, the most common form of respiratory distress in neonates.
- congenital-genetic-and-acquired-complications — Surfactant deficiency is an acquired physiologic complication of preterm birth.
- care-of-common-problems-in-the-newborn — Respiratory complications in the newborn context.
- oxygen-therapy — Supplemental oxygen is used alongside surfactant therapy in RDS management.
Self-Check
- A preterm infant at 28 weeks’ gestation is intubated and receiving beractant. During the second quarter-dose, SpO₂ drops to 82%. What is the priority nursing action?
- Why must suctioning be withheld for 1 hour after surfactant administration?
- After beractant administration, the nurse notes improved SpO₂ and a decrease in FiO₂ requirements. Is this a normal response or a complication?