Cheyne-Stokes respiration as an additional risk factor for pulmonary hypertension in a boy with trisomy 21 and atrioventricular septal defect.

: Central ventilation disorders(1) and airway obstruction(2) with chronic hypoxemia are causally related to cor pulmonale. Pulmonary vascular resistance is often reversible, and hypoxic pulmonary hypertension often responds to treatment with supplemental oxygen. Oxygen therapy during sleep may be useful as a temporary palliative treatment in children with obstructive sleep apnea syndrome (3) and Cheyne-Stokes respiration (CSR) in congestive heart failure(4). This type of sleep-related breathing disorder is characterized by periodic crescendo-decrescendo alterations in tidal volume. Proposed mechanism include an increased central nervous system sensitivity to changes in arterial PCO2 and PO2, a decrease in total body stores of CO2 and O2 with resulting instability in arterial blood gas tensions in response to changes in ventilation, and an increased circulatory time. Clinical features of obstructive and central sleep-related breathing disorders include daytime somnolence, unusual breathing patterns, failure to thrive, and cyanosis masquerading as cyanotic congenital heart disease(2). Down syndrome is often associated with cardiac malformations, left to right shunt, and the development of pulmonary hypertension(5). However, this may be exacerbated by sleep-related breathing disorders, as illustrated in the following case report.