Table 3—

Demographic, anthropometric, lung function and EMGdi % max data for COPD patients and healthy subjects matched for age, height, weight and BMI

HealthyCOPDp-value
Subjects n2630
Age yrs64.8±7.466.6±7.80.41
Height m1.66±0.11.66±0.080.79
Weight kg69.0±13.063.9±13.90.15
BMI kg·m−224.9±3.323.0±4.40.06
Male %50.073.30.10
FEV1 % pred110.8±16.934.8±13.9<0.001
VC % pred113.3±15.383.0±18.6<0.001
VT mL499.3±167.4608.3±199.40.03
VT % VCpred14.5±4.018.7±5.60.002
Tidal RMS-EMGdi per breath μV24.8±9.453.2±29.0<0.001
RMS-EMGdi,peak μV226.4±71.7188.9±68.80.052
EMGdi % max11.4±3.427.9±9.9<0.001
(VT % VCpred)/(EMGdi % max) AU1.4±0.60.8±0.4<0.001
  • Data are presented as mean±sd, unless otherwise stated. EMGdi: diaphragm electromyogram; % max: % maximum; COPD: chronic obstructive pulmonary disease; BMI: body mass index; FEV1: forced expiratory volume in one second; % pred: % predicted; VC: vital capacity; VT: tidal volume; % VCpred: percentage of predicted VC; RMS: root mean square; RMS-EMGdi,peak: peak RMS of spontaneous EMGdi activity; AU: arbitrary units.