Mean (SD) changes (Δ) between maximum work load and at rest for the two groups with and without CO2 retention independently. p values (t test) are given for the differences between the two groups
| CO2retention (n = 22) | No CO2 retention (n = 28) | p value | |
|---|---|---|---|
| ΔVE (l/min) | 31.4 (15.7) | 59.5 (24.8) | 0.000 |
| ΔVE%MVV (%) | 64.2 (18.2) | 60.4 (17.0) | 0.447 |
| ΔVt (l) | 0.54 (0.33) | 1.27 (0.59) | 0.000 |
| ΔPaco 2 (kPa) | 0.48 (0.33) | −0.50 (0.35) | 0.000 |
| ΔPao 2 (kPa) | −1.26 (1.51) | 0.63 (2.03) | 0.000 |
| ΔBE (mol/l) | −5.25 (1.94) | −6.79 (3.10) | 0.037 |
| ΔTTIi | 0.039 (0.052) | 0.067 (0.066) | 0.100 |
| ΔTTIe | 0.079 (0.083) | 0.056 (0.066) | 0.310 |
| ΔPtot (kPa) | 3.75 (1.98) | 3.13 (1.43) | 0.204 |
| ΔPtot% (%) | 20.7 (10.3) | 18.7 (11.0) | 0.525 |
| ΔWork (mW) | 5.09 (2.81) | 7.38 (4.58) | 0.123 |
| Δ(Vt/Ti) (l/s) | 2.86 (1.54) | 3.54 (1.71) | 0.151 |
| Δ(Pi/Ti) (kPa/s) | 6.52 (3.64) | 4.53 (2.27) | 0.031 |
| ΔDyspnoea score | 5.86 (2.61) | 5.91 (2.10) | 0.945 |
| ΔLeg score | 5.86 (2.30) | 7.25 (2.19) | 0.036 |
VE = minute ventilation; Vt = tidal volume; TTIi, TTIe = inspiratory and expiratory time tension index; Ptot = total pressure of the respiratory cycle; Ti = inspiratory time; Pi = inspiratory pressure.