Benefits at 1 year of nocturnal intermittent positive pressure ventilation in patients with obesity-hypoventilation syndrome

AbstractBackground: Patients with the obesity-hypoventilation syndrome (OHS) benefit from non-invasive ventilatory support. We assessed the long-term physiopathological response to 12-months of nocturnal ventilatory assistance at home with bi-level positive airway pressure (BiPAP) via nasal mask in patients with this disease.Methods: A series of 13 non-consecutive patients diagnosed of OHS (5 men and 8 women) with a mean (sd) age of 61.9 (8) years, underwent the following studies before (baseline) and after 12 months of non-invasive domiciliary mechanical ventilation: arterial blood gases, nocturnal digital pulse oximetry, spirometry, body plethysmography, maximum muscular respiratory pressures and ventilatory pattern with measurement of occlusion pressure (P0.1) before and after hypercapnia. An overnight cardiorespiratory polygraphy was done at baseline.Results: After 12 months of non-invasive mechanical ventilation, there were significant (P<0.05) reductions of arterial carbon dioxide tension (PaCO2) and increases in arterial oxygen tension, forced vital capacity and ventilatory response to hypercapnia, as measured by the relationship between changes of P0.1 and PaCO2 (ΔP0.1/ΔPaCO2) as well as respiratory minute volume (VE) and PaCO2 (ΔVE/ΔPaCO2). Changes of the PaCO2 correlated significantly with those in the (ΔP0.1/ΔPaCO2) slope (r=0.576, P