Peripheral edema in the sleep apnea/hypopnea syndrome

Abstract

To clarify the roles of lung function, nocturual hypoxemia and obesity in the development of peripheral edema in patients with the sleep apnea/hypopnea syndrome (SAHS), 65 consecutive SAHS patients had diagnostic sleep studies and respiratory function testing. Eighteen patients (27%) had peripheral edema without other explanation. Their sleep apnea/hypopnea index was similar to those without edema, but they were more obese (p < 0.01) and had worse lung function (p < 0.01) and lower oxygen saturation (SaO2) awake (p < 0.01). These 18 became more hypoxemic during sleep than predicted from their awake SaO2 (p < 0.005). Eleven patients with edema had evidence of pulmonary hypertension on cardiac catheterization, chest radiograph, or electrocardiograph and could be weight matched to 11 SAHS patients without edema. Those with right heart failure were more hypoxic (p < 0.01) when awake, desaturated more frequently during sleep (p < 0.01), and had lower FEV1 % predicted (p < 0.01). Thus, extent of both daytime and nighttime hypoxemia are important in the development of right heart failure in patients with SAHS.