Interaction between systemic circulation and brain injuries in newborns.

In several studies different pathogenetic mechanisms of metabolic and/or cardiovascular origin were shown depending on the type of hypoxic or hypoxic/hypercapnic stress and conditions of animals (normal developed or intrauterine growth retarded newborn piglets). Thus, in normal-weight piglets the prevention of compensatory hyperventilation owing to severe hypoxia (artificially ventilated animals) leads to critical, i.e. lethal acidosis. In intrauterine growth retarded piglets, a severe hypoxia cannot be vitally compensated because of the restricted circulatory centralization. Moreover, a limited cerebrovascular dilatation during moderate hypoxia/hypercapnia produces a critical state of the metabolic supply in those animals.