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Exogenous Surfactants |   |
| Surfactant is a surface-active agent that lowers surface tension. One of the most common examples is detergent. The term exogenous describing this class of drugs refers to the fact that surfactant preparations are obtained from outside the patient's own body (i.e., from other humans, from animals, or synthesized in the lab). |  |
Lung immaturity, which causes a lack of pulmonary surfactant is the primary problem in RDS. It results in high surface tension in the liquid-lined, gas filled alveoli. The clinical use of exogenous surfactants has traditionally been to replace the missing pulmonary surfactant of the premature, or immature, lung in respiratory distress syndrome (RDS) of newborns. These agents are also being investigated in treating adult respiratory distress syndrome (ARDS).
The clinical indications for exogenous surfactants are for the following applications:
- prevention of RDS in low birth weight infants
- prevention of RDS in other infants with evidence of immature lungs
- retroactive, or rescue treatment of infants with RDS
Exogeneous surfactants act to replace and replenish a deficient endogenous surfactant pool in neonatal respiratory distress syndrome. Exosurf, colfosceril palmitate, is a protein-free, synthetic surfactant preparation. An indication for its use is the presence or risk of RDS. Dosage is 5 ml/kg of the reconstituted suspension, given as two divided doses of 2.5 ml/kg by direct tracheal administration. Details of preparing the suspension should be reviewed in the manufacturer's literature.
Beractant (Survanta) is a modified natural surfactant that has similar indications as Exosurf, and the recommended dose is 100 mg/kg of birth weight. The primary complications in exogenous surfactant therapy are caused by the dosing procedure, and include: airway occlusion, high PaO2 levels, over-ventilation, apnea, and pulmonary hemorrhage.