Surfactant

Overview:

Surfactant is a complex mixture of lipids and proteins that lines the alveoli (tiny air sacs) in the lungs. It plays a crucial role in reducing surface tension within the alveoli, facilitating normal breathing and lung function.  Curosurf, also known as poractant alfa, is a natural surfactant used in neonatal care to treat respiratory distress syndrome (RDS) in preterm infants. RDS is a common condition in premature babies where the lungs are not able to produce enough surfactant, a substance that helps keep the air sacs in the lungs open. 

1. Indications for Delivering Curosurf: 

• Respiratory Distress Syndrome (RDS): Curosurf is primarily administered to preterm infants diagnosed with respiratory distress syndrome. In premature babies, the lungs may not have produced enough surfactant, leading to difficulty in breathing. 

• (MAS) Meconium Aspiration Syndrome: Many physicians prefer to use surfactant if severe meconium aspiration occurs. This can help break down the thick meconium and reduce surfact tension, improving oxygenation.

2. When to Administer Curosurf: 

• Shortly After Birth: Curosurf is typically administered shortly after birth if the baby is premature and at risk of or diagnosed with respiratory distress syndrome. The goal is to improve lung function by providing the surfactant that the baby's lungs are lacking. 

• As Part of Respiratory Support: Curosurf is often used as part of a comprehensive respiratory support plan, which may include mechanical ventilation or other non-invasive ventilation strategies. 

• Based on Clinical Assessment: The decision to administer Curosurf is based on a clinical assessment of the baby's respiratory status, gestational age, and the presence of risk factors for respiratory distress syndrome. 

3. How Curosurf Works: 

Curosurf is a natural lung surfactant derived from porcine lung extracts. Surfactant plays a crucial role in reducing surface tension in the lungs,

preventing the collapse of the alveoli (air sacs) during expiration. In infants with RDS, the lack of sufficient surfactant can result in atelectasis

(collapse of lung tissue) and respiratory distress. 

By delivering Curosurf, healthcare providers aim to supplement the insufficient surfactant, reducing surface tension and improving the baby's

ability to breathe. This intervention helps prevent or treat RDS and is an important component of neonatal respiratory care in preterm infants. 

4. Key Components: 

•  Phospholipids: These are the primary lipid components of surfactant and include substances such as phosphatidylcholine. 

• Proteins: Surfactant proteins (SP-A, SP-B, SP-C, and SP-D) contribute to the stability and function of surfactant. They help with the spreading and adsorption of the surfactant film. 

5. Functions: 

• Surface Tension Reduction: Surfactant reduces surface tension at the air-liquid interface within the alveoli. This prevents alveolar collapse during expiration and promotes lung inflation during inspiration. 

• Lung Compliance: By reducing surface tension, surfactant improves lung compliance, making it easier for the lungs to expand and contract. 

• Preventing Atelectasis: Atelectasis refers to the collapse of lung tissue. Surfactant prevents atelectasis by maintaining the patency of the alveoli. 

6. Production and Development: 

• Surfactant production begins in the fetal lung around the 24th week of gestation, with significant production occurring in the last trimester. 

• Premature infants, especially those born before 30 weeks of gestation, may have insufficient surfactant, leading to respiratory distress syndrome (RDS). 

7. Clinical Significance: 

• Surfactant deficiency is a major factor in the respiratory distress seen in premature infants. 

• Surfactant replacement therapy is a common intervention in the Neonatal Intensive Care Unit (NICU) for preterm infants with respiratory distress syndrome. 

8. Common Types of Surfactant in the NICU: 

a. Beractant: 

• Brand Name: Survanta 

• Composition: A natural surfactant derived from minced pig lungs. 

• Dose: Typically administered at a dose of 4 ml/kg. 

• Administration: Given intratracheally through an endotracheal tube. 

 b. Porcant Alpha

• Brand Name: Curosurf 

• Composition: A natural surfactant derived from porcine (pig) lungs. 

• Dose: Initial dose is usually 2.5 ml/kg initial dose, 1.25 ml/kg subsequent doses. Administration: Administered intratracheally through an endotracheal tube. 

9. Complications

a. Oxygen Desaturation and Bradycardia

• Oxygen desaturation occurs when the neonate’s blood oxygen levels drop below normal during or after surfactant administration. This can happen because the process of administering surfactant, which is often done via endotracheal tube, can temporarily disrupt ventilation or lead to a mismatch in ventilation and perfusion.

• Bradycardia (a slow heart rate) is another potential complication. This can occur during surfactant administration, often as a response to changes in oxygen levels or as a vagal response to the intubation or the procedure itself.

Management Tips:

• Pre-oxygenate the neonate before surfactant administration to avoid oxygen desaturation.

• Ensure proper intubation and suctioning techniques to minimize risk of airway obstruction.

• Be prepared to provide resuscitation or positive pressure ventilation (PPV) if bradycardia or significant desaturation occurs.

b. Pulmonary Hemorrhage

• Pulmonary hemorrhage refers to bleeding within the lungs, which can be a serious complication following surfactant therapy. It is more common in premature infants with very low birth weights and those who are already critically ill, such as infants with respiratory distress syndrome (RDS).

• The risk is thought to be due to the combination of delicate lung tissue, high positive pressure ventilation, and potential overdistension of the lungs during mechanical ventilation or surfactant delivery.

Management Tips:

• Use gentle ventilation strategies, and monitor ventilator settings closely to avoid barotrauma or volutrauma.

• Limit suctioning and avoid aggressive manipulation of the airway to minimize the risk of trauma to the lung tissue.

• In cases of pulmonary hemorrhage, ensure the infant is stable, maintain adequate oxygenation, and provide appropriate supportive care.

c. Airway Obstruction

• Airway obstruction can occur during or after surfactant administration, often due to the surfactant material itself becoming lodged in the airway or tube, especially if it’s not properly administered.

• Mucus or debris from the lungs may also mix with the surfactant, causing clogging or partial obstruction in the endotracheal tube. This can impair ventilation and oxygenation.

Management Tips:

• Ensure the endotracheal tube is clear before surfactant administration by suctioning if necessary.

• Administer surfactant slowly and under controlled conditions to reduce the risk of aspiration or blockage.

• Post-surfactant, monitor the airway closely and perform regular suctioning if needed to clear any excess surfactant or mucus.

Why is Surfactant important to an RT?

A Neonatal Intensive Care Unit (NICU) Respiratory Therapist (RT) plays a crucial role in the administration and management of surfactant therapy. Their responsibilities may include: 

• Assessment: Assessing the baby's respiratory status and the need for surfactant therapy. 

• Administration: Administering Curosurf according to the prescribed dosage and guidelines. 

• Monitoring: Monitoring the baby's response to treatment, including respiratory parameters and oxygenation.