Successful lung volume reduction improves inspiratory paradoxical movement of the lower rib cage at rest as measured by optoelectronic plethysmography

INTRODUCTION:Whether lung volume reduction(LVR) in patients with severe COPD improves inspiratory paradoxical chest wall movements has not been studied using 3-dimentional volume measurements of the chest wall. Optoelectronic plethysmography(OEP) allows breath by breath volume analysis of 6 chest wall compartments; left and right of each of pulmonary rib cage(Vrc,p), abdominal rib cage(Vrc,a) and abdomen(Vab). METHODS: 26 patients had OEP assessments during quiet breathing before and 3 months after LVR(LVR group (surgical n=9, bronchoscopic n=7)), or a sham bronchoscopy (control group, n=10). The phase shift angles were calculated for the asynchrony between Vrc,p and Vrc,a (θRC), and between Vrc,a and Vab (θDIA). RESULTS:At baseline, patients had severe airways obstruction(FEV 1 35(18)%pred) and hyperinflation(RV 218(42)%pred) and the groups were well matched. Between group difference in the change in θRC and θDIA was statistically significant in the direction of 0°(representing complete synchrony) favouring the LVR group . CONCLUSION:Successful LVR significantly improves chest wall asynchrony in patients with severe COPD.