Switch of Noninvasive Ventilation (NIV) to Continuous Positive Airway Pressure (CPAP) in Patients With Obesity Hypoventilation Syndrome

A Pilot Study

Sarah Orfanos; Dany Jaffuel; Christophe Perrin; Nicolas Molinari; Pascal Chanez; Alain Palot


BMC Pulm Med. 2017;17(50) 

In This Article


Obesity is a major worldwide public health issue.[1] The main respiratory complication stemming from obesity is obesity hypoventilation syndrome (OHS). OHS was defined, in 1999, by the American Academy of Sleep Medicine as the association of obesity (BMI ≥ 30 kg/m2); daytime hypercapnia (paCO2 > 45 mm Hg); and sleep disordered breathing, after excluding other causes of hypoventilation.[2] OHS is a frequent condition with the prevalence of OHS in patients with a BMI ≥ 35 kg/m2 being 31%.[3]

OHS is an underdiagnosed and undertreated condition,[3,4] despite the fact that a treatment with positive airway pressure improves quality of life and decreases morbidity in these patients.[3,5] The application of a positive airway pressure through noninvasive ventilation (NIV) or continuous positive airway pressure (CPAP), decreases mortality in patients presenting with OHS.[4,6,7]

To date, the main unresolved question is to determine the respective position of NIV and CPAP when treating these patients. If some studies have attempted to determine different OHS's phenotypes to predict the outcome of CPAP therapy;[8–10] only two studies prospectively compared NIV and CPAP treatment in OHS.[5,11] To date, the superiority of NIV over CPAP in the treatment of OHS has not been proven. However, 26 to 50% of patients suffering from OHS are diagnosed in an acute setting,[7,8,11,12] and most often treated with NIV which remains their usual ventilatory mode for the rest of their life.

Once stability has been reached, the question then arises as to whether NIV should be switched to CPAP. To our knowledge, no prospective trial has evaluated in real life conditions the feasibility of a protocol switching stable patients from NIV to CPAP.

The purpose of this study was to test the feasibility and effect of a standardized protocol, switching patients with OHS, from NIV to CPAP. We hypothesized that there will be no difference in efficacy after switching NIV to CPAP, on AHI, diurnal and nocturnal alveolar gas exchange (daytime arterial blood gas (ABG), nighttime transcutaneous oxygen saturation and transcutaneous measurement of pCO2 (ptCO2)), but also on sleepiness, quality of sleep and quality of life (Epworth Sleepiness Scale (EPS), Pittsburgh Sleep Quality Index (PSQI), Severe Respiratory Insufficiency questionnaire (SRI)).