Cystic fibrosis is a genetic defect leading to reduced secretions in various organs. The manifestation in the airways is the most prominent and problematic symptom. In the airways, the mucus secretions are exceptionally thick and sticky which provides the ideal environment for bacterial infections. The repeated infections cause continuous chemotaxis of neutrophils which then, during disintegration, deposits DNA in the mucus to make it even stickier. The mucus then becomes virtually impossible to clear and a vicious circle of sticky mucus and further infections results.
Dornase alfa (rhDNase I) hydrolyses extra-cellular DNA from the neutrophils in the bronchial mucus, increasing its liquidity drastically. It is related to the natural enzyme deoxyribonuclease I (DNase I) which is normally produced by the pancreas and salivary glands.
Neonatal respiratory distress syndrome is also known as hyaline membrane disease. The surface-active material which covers the respiratory unit of the airways is formed only in the last weeks of pregnancy. When babies are born prematurely, this surface-active material has not yet formed, resulting in disrupted gas exchange and also the possibility that the lungs may collapse. Treatment must follow rapidly in order to save the life of the premature baby.
The treatment includes:
Monitoring:
The intensive monitoring of respiratory and circulatory status is essential.
Oxygenation, continuous positive airway pressure:
Oxygen (mixed with air at room temperature) is administered in order to ensure oxygenation. A continuous positive pressure (as obtained with a ventilator) improves respiration and keeps the alveoli open to prevent collapse. It is critically important that the arterial partial oxygen pressure is continuously monitored.
Sufficient oxygen is a basic requirement for normal respiration. Therapeutically it is administered generally to prevent or reverse hypoxia (of various causes). When oxygen is inhaled in excessive quantities and/or over too long a period of time, it has toxic effects. Paradoxically, oxygen toxicity causes, inter alia, reduced gas exchange, hypoxia and, in extreme cases, death. In neonates, it can cause retinal damage and blindness.
These surfactants are administered exogenously at room temperature (by means of a catheter into the lungs), prophylactically, or during acute respiratory distress syndrome to the neonate to augment lung surfactant. Eventually, the mortality and long-term oxygen requirement are lowered. This therapy, however, is relatively expensive and specialised.
Corticosteroids
A short course of corticosteroids is also effective to boost endogenous surfactant production and is a cheaper alternative than the exogenous surfactant. When the baby is viable and there is an impending miscarriage, it can be administered prophylactically. Systemic administration of betamethasone to the mother just before labour can induce neonatal endogenous surfactant production within 24 hours.
Sufficient oxygen is a basic requirement for normal respiration. Therapeutically it is administered generally to prevent or reverse hypoxia (of various causes). When oxygen is inhaled in excessive quantities and/or over too long a period of time, it has toxic effects. Paradoxically, oxygen toxicity causes, inter alia, reduced gas exchange, hypoxia and, in extreme cases, death. In neonates, it can cause retinal damage and blindness.
Neonatal apnoea occurs when the respiratory centre in the medulla of the premature baby has not yet developed sufficiently to stimulate continuous breathing. The breathing centre is, therefore, still insensitive to the stimulating effect of carbon dioxide. Apnoea has a duration, typically, of longer than 15 seconds and is accompanied by bradycardia. Repeated episodes of apnoea with hypoxia can eventually lead to neural damage.
Methylxanthines, especially caffeine and theophylline, stimulate the central nervous system and intravenous administrations of these drugs usually help to solve the problem. Therapy is however, usually discontinued as soon as possible – usually after a few weeks in intensive care. The neonate then also receives oxygen therapy and the oxygen levels in the blood are continuously monitored.