Hypoxia due to congenital heart diseases (CHDs) adversely affects brain development during the fetal period. Head circumference at birth is closely associated with neuropsychiatric development, and it is considerably smaller in newborns with hypoplastic left heart syndrome (HLHS) than in normal newborns. We performed simulation studies on newborns with CHD to evaluate the cerebral circulation during the fetal period. The oxygen saturation of cerebral blood flow in newborns with CHD was simulated according to a model for normal fetal circulation in late pregnancy. We compared the oxygen saturation of cerebral blood flow between newborns with tricuspid atresia (TA; a disease showing univentricular circulation and hypoplasia of the right ventricle), those with transposition of the great arteries (TGA; a disease showing abnormal mixing of arterial and venous blood), and those with HLHS. The oxygen saturation of cerebral blood flow in newborns with normal circulation was 75.7 %, whereas it was low (49.5 %) in both newborns with HLHS and those with TA. Although the oxygen level is affected by the blood flow through the foramen ovale, the oxygen saturation in newborns with TGA was even lower (43.2 %). These data, together with previous reports, suggest that the cerebral blood flow rate is decreased in newborns with HLHS, and the main cause was strongly suspected to be retrograde cerebral perfusion through a patent ductus arteriosus. This study provides important information about the neurodevelopmental prognosis of newborns with HLHS and suggests the need to identify strategies to resolve this unfavorable cerebral circulatory state in utero.

Septic shock is associated with impaired vasoregulation, and treatment includes vasoactive drugs. Therefore, evaluation of vasoregulatory change is important. The present report describes the successful characterization of vasoregulatory change in response to a vasoactive drug during septic shock. A male infant born at 23 weeks' gestation developed septic shock. Severe hypotension developed, and treatment with colloid fluid and dopamine failed to increase blood pressure. With continuous measurement of skin blood flow using laser Doppler, noradrenaline was started. Based on changes in the blood flow, the dose was increased. At a dose of 1 μg/kg per min, skin blood flow in the foot decreased without any change in blood pressure. Subsequent blood transfusion succeeded in increasing both blood pressure and skin blood flow. It is concluded that decrease in foot blood flow reflects the vasoconstrictive effect of noradrenaline, although this finding must be validated in larger studies.

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