TY - JOUR T1 - Effect of posture on chest wall and diaphragm asynchronies in COPD JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p2122 AU - Rita Priori AU - Marco Quaranta AU - Andre L.P. Albuquerque AU - Peter M.A. Calverley AU - Andrea Aliverti Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p2122.abstract N2 - In COPD hyperinflation alters the function of the inspiratory muscles. The zone of apposition of the diaphragm (ZOM) is reduced, thus COPD patients often show paradoxical movement of the lower rib cage. The aim of this study is to investigate if in COPD chest wall and diaphragm asynchronies are altered by posture.24 severe COPD (FEV1=32.5±7.0%pred) and 12 age-matched controls (CTR) (FEV1=111.1±16.2) were studied during quiet breathing in seated (ST) and supine (SP) positions. Phase shift (θ) between pulmonary rib cage (RCp) and abdominal rib cage (RCa) and θ between RCp and the abdomen (AB) were assessed by opto-electronic plethysmography.The cranio-caudal displacement of the ZOM (ΔZOM) was contemporarily measured by ultrasonography.Neither θ between RCp and RCa or θ between RCp and AB was altered by posture in CTR. Conversely, in COPD patients, θ between RCp and RCa decreased when changing posture from ST to SP (θ=23.7°±19.5, θ=5.2°±18.1 respectively, p<0.001).RCp and AB in COPD showed a behavior similar to CTR while in ST (θ=1.3°±13.3 in COPD, θ=0.1°±4.5 in CTR), but strongly differed in SP (θ= -25.0°±18.2, p<0.001; p<0.01, COPD vs. CTR).Moreover, in COPD ΔZOM was linearly correlated to RCp in ST (r2=0.718±0.140), similarly to control subjects (r2=0.729±0.150), while it was significantly less correlated to RCa (r2=0.510±0.246, p<0.01).In COPD correlation between ΔZOM and both RCp and RCa decreased (r2=0.530±0.244, r2=0.511±0.230 p<0.05) in SP.In COPD the diaphragm and RCa are uncorrelated in ST, but the synchronous action of the rib cage muscles and the diaphragm is similar to healthy. In SP the diaphragm is uncorrelated with both RCp and RCa, so the asynchrony with the rib cage muscles seems to be pronounced. ER -