1. Cystic fibrosis is a genetic defect leading to reduced secretions in various organs. 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 cycle of sticky mucus and further infections results.

Dornase alfa hydrolyses extra-cellular DNA from the neutrophils in the bronchial mucus and increases its liquidity.

2. It is a condition where the surface-active material which covers the respiratory unit of the airways has not yet formed is formed when babies are born prematurely resulting in disrupted gas exchange and also the possibility that the lungs may collapse.

The general treatment strategies include monitoring where the intensive monitoring of respiratory and circulatory status is essential as well as oxygenation and continuous positive airway pressure where oxygen is administered in order to ensure oxygenation.  A continuous positive pressure improves respiration and keeps the alveoli open to prevent collapse.

When exogenous surfactants are administered the mortality and long-term oxygen requirement are lowered. When corticosteroids are administered it boosts endogenous surfactant production.

3. It is administered generally to prevent or reverse hypoxia. Oxygen toxicity causes reduced gas exchange, hypoxia and, in extreme cases, death.  In neonates, it can cause retinal damage and blindness.

4. It occurs when the respiratory centre in the medulla of the premature baby has not yet developed sufficiently to stimulate continuous breathing. Methylxanthines stimulate the central nervous system. Theophylline and caffeine are used.