It is a complex mixture of lipids, proteins, and specific carbohydrates, secreted by the epithelial cells to the alveolar space.
Pulmonary surfactant is 80% phospholipids, 12% corresponds to proteins, and 8% to other lipids.
Its primary function is to reduce the surface tension at the air / liquid interface in the lung’s alveoli.
Premature babies born with immature lungs and a deficiency of surfactant develop a syndrome of respiratory distress after birth.
The replacement therapy of pulmonary surfactant used in premature babies during this last decade has significantly increased their survival and reduced the probability of significant pulmonary sequelae in neonates.
Although premature babies are the primary population, treatment for respiratory diseases may play an essential role in other diseases of this same type in full-term babies and older children.
However, in the case of adult patients, this therapy has not achieved the success observed in the child population.
Substitution therapy of natural surfactant by purified surfactant from lungs of non-human species is one of the most significant advances in neonatology.
These exogenous surfactants have been available for more than two decades; those of natural origin and synthetic ones are used.
Natural surfactants come from lung lavage or lung extracts from cattle or pigs.
These substances are subjected to extraction and purification processes, and the addition of supplementary compounds is required to achieve an optimum activity of decreasing the surface tension.
Synthetic surfactants originate from the mixture of phospholipids, proteins, and supplementary compounds to provide activity as an active tensing agent.
The number of phospholipids to be supplied per body weight should be considered to estimate the dosage.
The only disease where the dosage estimates have been studied is neonatal respiratory distress syndrome.
The recommended phospholipid dose is 100 mg/kg of weight.
The frequency with which the active tense agent is applied will depend on the patient’s clinical condition.
The repetition of the treatment is usually done at intervals of 6 to 24 hours.
Administration of pulmonary surfactant therapy
Different therapy methods include intratracheal bolus administration through an endotracheal tube, aerosolization, and bronchoscopic administration of the dilute active surfactant to remove mediators and inhibitors of inflammation.
At this time, the treatment administration is done in bolus due to its relative ease.
The replacement of pulmonary surfactant can be provided as: prophylactic or preventive treatment in which the surfactant is administered at birth or shortly after in infants with a high risk of developing the disease, and treatment in which surfactant is administered after the start of mechanical ventilation in newborns with the clinically confirmed syndrome, according to clinical data and chest x-ray.
To start treatment, hypothermia, hypoglycemia, and hypovolaemia must be controlled as they are essential aspects of the treatment. Their correction is recommended before the administration of the active tense agent.
Treatment begins with the placement of a saturation probe, and oxygen saturation monitoring should be performed.
Prior chest radiographs should be performed to confirm the diagnosis and ensure proper endotracheal tube placement before administering the pulmonary surfactant.
Heart rate monitoring and oxygen saturation are required after starting assisted ventilation.
The placement of a peripheral arterial line or umbilical arterial line is desirable but optional.
Antibiotics should be given to prevent infections.
Among the risks or side effects that may arise from the application of pulmonary surfactant therapy and the therapies that accompany it:
- Blockage of the endotracheal tube
- Oxygen desaturation
- Possibility of pneumothorax due to sudden changes in lung compliance
- Irritation can cause bleeding in the lungs
- Damage to lung tissue due to inadequate oxygen pressure
Some risks can be avoided by taking the necessary precautions, such as precise procedures and constant supervision.