Introductions:
Surfactant is a complex mixture of phospholipids (80%) proteins (10%) and neutral lipids (10%). Major Phospholipid is phosphatidyl choline and there are 4 surfactant specific protein SP-A. SP-B, SP-C and SP-D among which SP-B has get major surface tension lowering activity.
After the discovery that surfactant deficiency is responsible for pathophysiology of RDS surfactant therapy became popular.
Types of surfactant:
| Natural: - |
Surfactant TA
Survanta (Beractant)
Infasurf (Calfactant)
Alveo fact |
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Bovine Lung |
Curosurf-Porcine long (Poractant Alfa) |
| Synthetic:- |
Exosurf
Lubricant/Sinaptitude/KL4
Pumactant 7 (AIEC)
Venticute (rsPC) |
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Indications:
- RDS-useful both in prevention and treatment
Prophylactic - Birth weight <1200 gm
Larger Neonates with evidence of pulm. Immaturity
- Criteria: Premature infants on CPAP with arterial / alveolar 02
Tension ratio i.e., a/APO2-0.22-0.35 (mean 0.26)
Neonate with moderate to severe RDS
- Criteria: infants requiring mechanical ventilation
- Fractional Concentration of inspired 02 i.e., FiO2> 40%
- Mean airway pressure> 0.6 Kpa (7 cm H2o)
- In term infants and older children-respiratory failure due to
- MAS
- Pneumonias
- PPHN
- BPD
- Acute Lung injury.
- As vehicle to carry other therapeutic agents e.g., rh SOd (recombinant human super oxide dismutase).
Benefits:
Improves Oxygenation; Reduces air leaks (Pneumothorax / Pulm interstitial Emphysema by 50%).
- Reduces duration of ventilatory support
- Lowers mortality rate by 30%
- Neither beneficial nor delirious effect on growth and neuro developmental parameter.
- Inconclusive data to support reduction in IVH / NEC / R.O.P. or CLD.
Dosage and Administration
- Survanta - 4 ml/kg/dose at least 6 hrs apart (maxm 4 dose)
- Infasurf - 3 ml/kg/dose (12 hrs apart)
- Exosurf - 5 ml/kg/dose at least 12 hrs apart
- Curosurf - 2.5 ml/kg/dose (initial) 1.25 ml/kg letter at least 12 hrs apart.
Method of Administration:
As bolus intratracheally through ET tube by instillation into a 5 French end hole catheter inserted through ET tube with the tip of catheter inserted just beyond the end of ET tube and above the infant's carina. It can also be given via a side port adapter.
Considerations:
-
Not to shake vials: open vials can be kept at 2-8 degree C is open vials should not be frozen.
- Suction ET tube before administration and delay suctioning post administration as long as possible
(minimum 1 hour).
- Slow administration by infusion pump / Nebulization has not shown improved result.
Monitoring:
-
Access: ET tube potency and correct anatomic location before administration of surfactant.
- Monitor so2 & HR continuously during administration of doses
- After each dose monitor ABG and correct it if abnormal.
Adverse Reaction : - Transient Bradycardia, Hypoxemia, Pallor, Vasoconstriction, Hypotension, ET tube blockage, Hypercapnea, Apnea, HTN may occur.
Key Messages:
Surfactant reduces death in premature neonates with respiratory distress syndrome.
Surfactant should be administrated early in neonates requiring mechanical ventilation for RDS.
Surfactant therapy is cost effective in developing countries and antenatal steroids / CPAP / supportive care is important to improve outcomes.
