Obesity Hypoventilation Syndrome—A Concise Clinical Review

O besity hypoventilation syndrome (OHS) is defined by the presence of awake hypoventilation in the setting of obesity.As nearly 1 in 10 adults today have a body mass index ≥30 kg/m 2 , increased prevalence of this severe consequence of obesity is expected.Sleep disordered breathing, in the form of obstructive sleep apnea or sleep-related hypoventilation, is present in almost all individuals with OHS.Diagnosis requires arterial blood gas measurement, which may not be readily available in the outpatient setting.Delays in diagnosis are common, with some patients only presenting when hospitalization is required for acute or chronic respiratory failure.Positive airway pressure therapy is the mainstay of treatment, as it has been shown to treat sleep disordered breathing and resolve daytime hypercapnia.Weight-loss interventions, especially bariatric surgery, can improve OHS as well.Untreated OHS leads to increased morbidity and mortality; thus recognition, diagnosis, and patient-centered shared decision-making are key.