[Apnea in premature infants. Epidemiology, pathophysiology and possibilities for prevention].

The pathogenesis of apnoea in preterm infants is poorly understood. Thus, it is yet unknown (1) whether the descriptive distinction between "central", "obstructive" and "mixed" apnoeas is also reflected by differences in their respective pathogenesis, (2) how and where the airway closure occurs during the so-called "obstructive" apnoeas, (3) whether "central" apnoeas do indeed result from a disturbance in the central nervous control of breathing, as implied by their name, or whether they constitute a reflex response to a disturbance in the periphery of the lung, and (4) whether non-apnoeic mechanisms contribute to the hypoxaemia so frequently observed during these episodes. This paper summarises the present knowledge regarding the above issues. It also reviews the current definitions for apnoea, bradycardia and hypoxaemia in preterm infants, describes indications for intervention, and discusses some strategies aimed at preventing these episodes.