Table 4—

Correlation coefficients of linear regression between changes (Δ) in arterial carbon dioxide tension (Pa,CO2) and in dynamic intrinsic positive end-expiratory pressure (PEEPi) with changes in various lung function tests

ΔPa,CO2 mmHgΔPEEPi,dyn cmH2O
ΔPI/VT/tI cmH2O·L−1·s−10.69<0.00010.77<0.0001
ΔVT L−0.69<0.0001−0.53<0.005
ΔFEV1 L−0.62<0.0001−0.39<0.05
ΔEL,dyn cmH2O·L−10.62<0.00010.40<0.05
ΔPI, cmH2O0.59<0.00010.72<0.0001
ΔFEF25–75% L·s−1−0.57<0.0001−0.31ns
ΔFRC L0.56<0.0010.46<0.01
ΔIC L−0.55<0.001−0.43<0.02
ΔRL cmH2O·L−1·s−10.54<0.0050.65<0.0001
ΔP0.1/VT/tI cmH2O·L−1·s−10.53<0.0050.38<0.05
  • PEEPi,dyn: dynamic intrinsic positive end-expiratory pressure

  • PI: mean inspiratory pressure swing

  • PI/VT/tI: effective inspiratory impedance of the lung

  • VT: tidal volume

  • TTI: tension/time index of the inspiratory muscles

  • FEV1: forced expiratory volume in one second

  • PI,max: maximal inspiratory pressure

  • E L,dyn: dynamic lung elastance

  • FEF25–75%: forced mid-expiratory flow

  • FRC: functional residual capacity

  • IC: inspiratory capacity

  • RL: inspiratory lung resistance

  • P0.1/VT/tI: effective impedance of the respiratory system

  • ns: nonsignificant