Obesity Hypoventilation Syndrome

As the prevalence of obesity continues to rise, morbidity associated with obesity becomes more and more endemic. Of particular interest to pulmonary and sleep medicine physicians is the entity of obesity hypoventilation syndrome (OHS), formerly known as Pickwickian syndrome. Most patients with OHS also will be found to present with obstructive sleep apnea (OSA), which appears to play a major role in the pathogenesis of OHS. With or without OSA, the etiology of OHS may also be related to the extreme mechanical limitations imposed by obesity on the ventilatory apparatus. Treatment of OHS has been profoundly changed by the advent of non-invasive positive pressure therapies, including continuous positive airway pressure, bilevel positive airway pressure, and average volume-assured pressure support. Despite these advances, morbidity and mortality remain elevated in these individuals unless substantial weight loss can be achieved.