Chapter 138 - Obesity-Hypoventilation Syndrome

Abstract

Obesity-hypoventilation syndrome (OHS) is defined by the combination of obesity and daytime hypercapnia during wakefulness occurring in the absence of an alternative neuromuscular, mechanical, or metabolic explanation for hypoventilation. This syndrome is also invariably accompanied by sleep-disordered breathing (e.g., obstructive sleep apnea or sleep hypoventilation). During the last 3 decades the prevalence of extreme obesity has markedly increased in the United States and other countries. With such a global epidemic of obesity the prevalence of OHS is likely to increase. Patients with OHS have a lower quality of life with increased health care expenses and are at higher risk of developing pulmonary hypertension and early mortality because of cardiopulmonary complications, compared with similarly obese eucapnic patients with obstructive sleep apnea. OHS often remains undiagnosed until late in the course of the disease. Early recognition is important, as these patients have significant morbidity and mortality if left untreated. Effective treatment can lead to significant improvement in patient outcomes, underscoring the importance of early diagnosis.