Difficulties in the hemodynamic assessment of the newborn with prenatally treated congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is a malformation with a diverse clinical picture. Its severity can be assessed prenatally using the lung area to head circumference ratio (LHR). LHR lower than 1 as associated with high mortality is an indication for prenatal treatment involving occlusion of fetal trachea. Before such treatment other congenital malformations must be excluded. Assessment of circulatory system in these patients is difficult. Heart is compressed by viscera in the thorax that decreases blood return to the left atrium, and structures of the left heart may be smaller than in healthy fetuses. The echocardiographic picture may be similar to some congenital defects of the left heart. Differentiation between structural and functional cardiac abnormalities is difficult but essential for diagnostic and therapeutic decisions in the most severe type of CDH. The authors present problems with interpretation of hemodynamic disturbances in a neonate with prenatally diagnosed and treated severe CDH.