Table 1—

General characteristics of study population

ControlsCOPD group
Subjects n79
Age yrs65±368±2
Height cm168±3167±2
Weight kg75.3±4.273.4±4.3
BMI kg·m−226.5±1.026.3±1.3
FEV1 % pred86±352±4***
FVC % pred84±261±5**
TLC % pred91±3102±7
RV % pred100±9155±21*
ITGV % pred102±7129±17
PI,max % pred82±2286±26
Poes,max cmH2O−76±14−67±22
Pdi,max cmH2O99±1988±58

  • Data are presented as mean±sd

  • COPD: chronic obstructive pulmonary disease

  • BMI: body mass index

  • FEV1: forced expiratory volume in one second

  • FVC: forced vital capacity

  • TLC: total lung capacity

  • RV: residual volume

  • ITGV: intrathoracic gas volume

  • PI,max: maximal inspiratory pressure measured at the mouth (Müller manoeuvre)

  • Poes,max: maximal oesophageal pressure during sniff manoeuvre

  • Pdi,max: maximal transdiaphragmatic pressure during sniff manoeuvre

  • % pred: percentage of the predicted value

  • *: p<0.05

  • **: p<0.01

  • ***: p<0.001 versus controls