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NIV and CPAP improve pulmonary pressures in OHS

Obesity hypoventilation syndrome (OHS) is a particularly serious type of sleep disordered breathing characterized by awake hypercapnia. OHS is also associated with greater risk of cardiovascular morbidity, including pulmonary hypertension. The optimal treatment strategy of obesity hypoventilation syndrome (OHS) has long vexed sleep clinicians and researchers, especially among the 70% of patients with OHS and comorbid severe obstructive sleep apnea (OSA). Luckily new research provides much needed answers. Recent trials among patients with OHS and severe OSA show non-invasive ventilation (NIV) and continuous positive airway pressure (CPAP) achieve comparable improvements in sleep symptoms, gas exchange, and lung volumes. In contrast, a medium-term (2 month) analysis of the Spanish Pickwick trial showed improvements in pulmonary arterial pressures with NIV but not CPAP. 

As published online in AJRCCM, Dr. Masa and his coauthors report on long-term (3 year) echocardiographic outcomes of their Pickwick trial. Unlike the medium term analyses, the authors found both NIV and CPAP groups experienced improvements in pulmonary arterial systolic pressure (CPAP: 40.5± (SE) 1.47 mmHg at baseline to 35.3±1.33 mmHg at follow up; NIV: 41.5±1.56 mmHg baseline to 35.5±1.42 at follow up).  Follow-up pulmonary artery pressures did not differ between groups (0.2 mmHg, 95 % CI -3.7 to 4.1). It is important to note that the degree of elevation in pulmonary systolic pressure was relatively modest in both groups.

Overall, these results suggest CPAP and NIV offer comparable improvements in pulmonary systolic pressures. These results support the current ATS guidelines recommending CPAP as first-line therapy for patients with OHS and concomitant severe OSA.

(Post by: Lucas Donovan)