INFLUENCE OF NONINVASIVE VENTILATION ON T HE WORK OF BREATHING IN OBESITY

Background: Noninvasive ventilation with nose- or facemasks has been i ncreasingly used in the past. The objective of mechanical ventilation is in addition to improve gas exchange to reduce breathing work. While improvement on breathing work has been shown mainly on normal-weight patients with different respiratory diseases, there is no existing dat a about the effect of noninvasive ventilation on the breathing work of patients with massive obesity. Patients and Methods: Assisted mask-ve ntilation with bilevel positive airway pressure (BiPAP) was carried ou t on 5 overweight control subjects (overweight controls), 7 overweight patients with obstructive sleep apnea (OSA), 6 patients with obesitas -hypoventilation syndrome (OHS), and 7 overweight patients with chroni c obstructive lung disease (COLD). Inspiratory pressure assist (IPAP) was set to 12 or 16 cm H2O, exspiratory pressure (EPAP) was set to 5 c m H2O. All subjects were massive overweight (body mass index [BMI] 42, 2+/-5,8; range 31,8 to 55,4 kg/m(2)). Respiratory muscle activity was measured as esophageal pressure change (Delta Pes) and transdiaphragma tic pressure change (Delta Pdi) and calculated as pressure time integr al. Results: With noninvasive ventilation respiratory muscle activity was significantly (p <0.05) reduced ill all groups at least 40% compar ed to baseline values during spontaneous respiration. Conclusions: Non invasive ventilation via face masks can efficiently reduce work of bre athing in subjects with massive obesity.