RIGHT-TO-LEFT SHUNT THROUGH A VENTRICULAR SEPTAL-DEFECT DURING SEDATED SLEEP

A 10-month-old infant with Down's syndrome developed cyanosis due to a right-to-left shunt through a ventricular septal defect during sedate d sleep induced for echocardiography. During cardiac catheterization, arterial oxygen saturation decreased, and arterial carbon dioxide conc entration increased. Various echocardiographic parameters during sedat ed and natural sleep were compared. It was considered that hypoventila tion caused by the narrowed upper airway was induced by sedated sleep, We conclude that the influence of sedatives should be considered in t he estimation, of echocardiographic data if an infant with Down's synd rome has a ventricular septal defect with pulmonary hypertension.