Pulmonary surfactant (medication)

Pulmonary surfactant is a complex mixture of lipids and proteins that is secreted into the alveolar space by type II alveolar cells. The primary function of pulmonary surfactant is to lower the surface tension at the air/liquid interface within the lung, thereby preventing atelectasis at the end of expiration.

Composition

Pulmonary surfactant is composed primarily of phospholipids and proteins. The most abundant phospholipid in surfactant is dipalmitoylphosphatidylcholine (DPPC), which is responsible for the surface tension-lowering properties of surfactant. The proteins in surfactant are categorized into two groups: hydrophilic surfactant proteins (SP-A and SP-D) and hydrophobic surfactant proteins (SP-B and SP-C).

Function

The primary function of pulmonary surfactant is to lower the surface tension at the air/liquid interface within the lung, thereby preventing atelectasis at the end of expiration. This is achieved by the adsorption of surfactant phospholipids at the air/liquid interface, which reduces the surface tension and therefore the pressure required to inflate the alveoli.

Pulmonary Surfactant as a Medication

Pulmonary surfactant is used as a medication in the treatment of respiratory distress syndrome (RDS) in premature infants. RDS is caused by a deficiency of surfactant in the lungs of premature infants. The administration of exogenous surfactant can reduce the severity of RDS and improve survival rates.

Types of Surfactant Medication

There are several types of surfactant medication available, including natural surfactants and synthetic surfactants. Natural surfactants are derived from animal lungs and contain both surfactant lipids and proteins. Synthetic surfactants are made from artificial compounds and may not contain surfactant proteins.

Administration

Surfactant medication is usually administered via an endotracheal tube directly into the lung. The medication is often given shortly after birth to premature infants at risk of developing RDS.

Side Effects

Potential side effects of surfactant medication include transient bradycardia, oxygen desaturation, endotracheal tube blockage, and pulmonary hemorrhage. However, these side effects are generally outweighed by the benefits of surfactant administration in premature infants with RDS.

See Also

• Respiratory distress syndrome
• Atelectasis
• Phospholipid
• Surfactant proteins