VENTILATORY STRATEGY IN HYPOXIC OR HYPERCAPNIC NEWBORNS

In conscious newborns, the ventilatory response to hypoxia is characte rized by precocious hyperventilation followed by tardive hypoventilati on, the latter disappearing with age. The hypoventilation could be mai nly related to a weak peripheral drive and to the persistence of the d iaphragmatic activity during expiration. Also, a decrease in metabolic rate and body temperature interferes with the response. The hypervent ilation in response to hypercapnia increases as maturation proceeds an d the maturation of the peripheral chemoreceptors contribute to this e ffect, as during hypoxia. The responses to both. stimuli depend on man y factors such as sleep state, anesthesia or ambient temperature.