Physiological Role and Functions
Natural endogenous surfactantes are synthesized by alveolar type II cells (pneumocyti) (alveolar epithelial cells). Chemically, they are surface-active agents. By lining the inner surface of the lungs, they perform several vital tasks:
- Antiatelectatic function: prevents alveolar collapse.
- Cytoprotective function: protects alveolar cells.
- Rheological function: regulates the physical properties of bronchopulmonary secretions.
- Mucociliary function: facilitates sputum clearance.
Deficiency of these substances leads to respiratory distress syndrome (RDS), accompanied by multiple atelectasis and interstitial parenchymal edema. Risk groups include premature newborns with impaired biosynthesis, as well as adults with bronchopulmonary diseases.
Clinical Pharmacology and Indications
The primary indication for this group of medications is respiratory distress syndrome, which occurs predominantly in newborns. These drugs temporarily compensate for the lack of endogenous protective compounds, restoring normal breathing.
Therapy is conducted exclusively in specialized clinical settings. A mandatory requirement for administering such medications is the availability of mechanical ventilation equipment (MV) and apparatus for continuous monitoring of the patient's vital functions.
Drug Characteristics: Curosurf and Exosurf
Various formulations are used in medical practice with distinct origins and compositions:
- Poractant alfa (Curosurf) — a natural medication derived from porcine lung tissue. Its basis is a phospholipid fraction with a predominance of phosphatidylcholine and the addition of 1% low-molecular-weight hydrophobic proteins. It is prescribed for premature infants with a birth weight of 700 g or more to restore adequate breathing.
- Colfosceril palmitate (Exosurf) — a synthetic drug whose active ingredient is colfosceril palmitate (dipalmitoylphosphatidylcholine). It improves lung tissue distensibility, increasing lung compliance. It is administered endotracheally via instillation through an endotracheal tube as a solution at a dose of 5 mL/kg. If necessary, repeat administration is permitted after 12 hours at the same dosage.