PT - JOURNAL ARTICLE AU - Juan F. Masa AU - Jean-Louis Pépin AU - Jean-Christian Borel AU - Babak Mokhlesi AU - Patrick B. Murphy AU - Maria Ángeles Sánchez-Quiroga TI - Obesity hypoventilation syndrome AID - 10.1183/16000617.0097-2018 DP - 2019 Mar 31 TA - European Respiratory Review PG - 180097 VI - 28 IP - 151 4099 - http://err.ersjournals.com/content/28/151/180097.short 4100 - http://err.ersjournals.com/content/28/151/180097.full SO - EUROPEAN RESPIRATORY REVIEW2019 Mar 31; 28 AB - Obesity hypoventilation syndrome (OHS) is defined as a combination of obesity (body mass index ≥30 kg·m−2), daytime hypercapnia (arterial carbon dioxide tension ≥45 mmHg) and sleep disordered breathing, after ruling out other disorders that may cause alveolar hypoventilation. OHS prevalence has been estimated to be ∼0.4% of the adult population. OHS is typically diagnosed during an episode of acute-on-chronic hypercapnic respiratory failure or when symptoms lead to pulmonary or sleep consultation in stable conditions. The diagnosis is firmly established after arterial blood gases and a sleep study. The presence of daytime hypercapnia is explained by several co-existing mechanisms such as obesity-related changes in the respiratory system, alterations in respiratory drive and breathing abnormalities during sleep. The most frequent comorbidities are metabolic and cardiovascular, mainly heart failure, coronary disease and pulmonary hypertension. Both continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV) improve clinical symptoms, quality of life, gas exchange, and sleep disordered breathing. CPAP is considered the first-line treatment modality for OHS phenotype with concomitant severe obstructive sleep apnoea, whereas NIV is preferred in the minority of OHS patients with hypoventilation during sleep with no or milder forms of obstructive sleep apnoea (approximately <30% of OHS patients). Acute-on-chronic hypercapnic respiratory failure is habitually treated with NIV. Appropriate management of comorbidities including medications and rehabilitation programmes are key issues for improving prognosis.Extreme weight loss is the ideal treatment for obesity hypoventilation syndrome but is difficult to achieve without bariatric surgery. These patients can have higher risk for this surgery. Therefore, positive airway pressure is the first-line treatment. http://ow.ly/IFyf30nxrAv