| Placebo | Ipratropium bromide | p Value | |
| Dyspnoea (Borg) | 7.4 (2.4) | 6.6 (2.4) | 0.07 |
| Dyspnoea/V̇e (Borg/l/min) | 0.12 (0.05) | 0.10 (0.05)* | |
| Leg discomfort (Borg) | 8.3 (1.7) | 7.5 (2.1)* | |
| V̇o2 (l/min) | 1.72 (0.54) | 1.82 (0.66) | |
| V̇co2 (l/min) | 1.67 (0.56) | 1.71 (0.62) | |
| Heart rate (beats/min) | 137 (19) | 136 (19) | |
| Spo2 (%) | 96 (3) | 96 (2) | |
| V̇e (l/min) | 65.7 (19.6) | 69.0 (24.9) | |
| F (breaths/min) | 36.7 (8.3) | 35.3 (8.2) | |
| Vt (l) | 1.83 (0.57) | 1.99 (0.65)* | |
| IC (l) | 2.51 (0.70) | 2.63 (0.66)* | |
| ΔIC isotime-rest (l) | −0.55 (0.40) | −0.49 (0.33) | |
| IRV (l) | 0.68 (0.31) | 0.64 (0.30) | |
| Ti (s) | 0.77 (0.20) | 0.81 (0.21) | |
| Te (s) | 0.93 (0.20) | 0.98 (0.23) | 0.06 |
| Ti/Ttot | 0.45 (0.03) | 0.45 (0.03) | |
| Vd/Vt estimated (%) | 30 (7) | 29 (8)* | |
| Petco2 (mm Hg) | 35.4 (5.1) | 34.3 (5.5) | |
| EFL (% of Vt overlapping maximal flow-volume curve) | 78 (13) | 62 (20)* |
Values are mean (SD).
*p<0.05 ipratropium bromide vs placebo.
EFL, expiratory flow limitation; IC, inspiratory capacity; IRV, inspiratory reserve volume; Petco2, partial pressure of end-tidal CO2; Spo2, oxygen saturation; Ti/Ttot, inspiratory duty cycle, inspiratory time over total breath time; V̇o2, oxygen uptake; V̇co2, carbon dioxide production; V̇e, minute ventilation; F, breathing frequency; VC, vital capacity; Vd, estimated dead space; Vt, tidal volume.