Apnoea of Prematurity

Expansion

Features of immature respiratory control:

• Biphasic hypoxic response: transient hyperventilation for a minute or so, then respiratory depression and apnoea. The adult pattern of sustained hyperventilation develops over the first weeks
• Blunted carbon dioxide response
• Periodic breathing, with cycles of breathing and short pauses
• Highly compliant chest wall, so effort is inefficient and the ribs recess rather than the lungs expanding
• Immature upper airway control, so obstructive and mixed apnoeas occur
• Fatigue-prone diaphragm with fewer type I fibres

Apnoea is defined as a pause of more than 20 seconds, or shorter if accompanied by bradycardia or desaturation.

Caffeine is the mainstay of treatment: it is a central stimulant, increases chemoreceptor sensitivity and improves diaphragmatic contractility, and it has been shown to reduce bronchopulmonary dysplasia and improve neurodevelopmental outcome.

Any new apnoea in a neonate should also prompt a search for sepsis, hypoglycaemia, seizures and intracranial haemorrhage.