Measurements at isotime (4.1 (0.8) minutes) during constant load cycle exercise
| Variable | RA + PL | RA + BD | O2 + PL | O2 + BD | p value (ANOVA) |
|---|---|---|---|---|---|
| Values are mean (SE). | |||||
| *p<0.05 v RA+PL; †p<0.05 v RA+BD; ‡p<0.05 v O2+PL. | |||||
| RA, room air; BD, bronchodilator; PL, placebo; O2, oxygen; V̇co2, carbon dioxide output; V̇e, minute ventilation; F, breathing frequency; Ti, Te, inspiratory and expiratory time; Vt, total volume; IC, inspiratory capacity; Sao2, arterial saturation; IRV, inspiratory reserve volume; EELV, end expiratory lung volume; EILV, end inspiratory lung volume; TLC, total lung capacity; Petco2, end tidal carbon dioxide tension; Paco2, arterial carbon dioxide tension; HCO3−, bicarbonate. | |||||
| Dyspnoea (Borg) | 3.9 (0.4) | 2.5 (0.4)* | 2.4 (0.4)* | 2.1 (0.5)* | <0.0005 |
| Leg discomfort (Borg) | 3.4 (0.4) | 2.9 (0.4) | 2.5 (0.4)* | 2.6 (0.4)* | 0.054 |
| Heart rate (beats/min) | 118 (4) | 118 (4) | 111 (4)*† | 114 (4)*† | <0.0005 |
| Sao2 (%) | 93 (1) | 93 (1) | 97 (1)*† | 98 (0)*† | <0.0005 |
| V̇co2 (l/min) | 1.10 (0.11) | 1.16 (0.12) | 1.13 (0.12) | 1.16 (0.14) | 0.463 |
| V̇e, (l/min) | 37.8 (3.0) | 40.0 (3.3) p = 0.06 v RA+PL | 34.5 (2.6)*† | 36.7 (3.5)† | <0.0005 |
| V̇e/V̇co2 | 36.5 (1.8) | 36.5 (1.8) | 32.6 (1.6)*† | 33.7 (1.7)*† | <0.0005 |
| F (breaths/min) | 34 (2) | 31 (2)* | 29 (2)* | 29 (2)*† | <0.0005 |
| Ti (s) | 0.75 (0.03) | 0.84 (0.04)* | 0.84 (0.04)* | 0.88 (0.05)* | <0.0005 |
| Te (s) | 1.09 (0.05) | 1.21 (0.08)* | 1.25 (0.07)* | 1.31 (0.09)*† | <0.0005 |
| Vt (l) | 1.15 (0.09) | 1.33 (0.11)* | 1.19 (0.09)*† | 1.30 (0.11)*‡ | <0.0005 |
| IC (l) | 1.53 (0.11) | 1.78 (0.13)* | 1.57 (0.10)† | 1.74 (0.12)*‡ | <0.0005 |
| IRV (l) | 0.37 (0.04) | 0.45 (0.07) | 0.38 (0.04) | 0.45 (0.04) | 0.310 |
| EELV (l) | 5.15 (0.21) | 4.80 (0.22)* | 5.20 (0.22)† | 4.84 (0.20)*‡ | <0.0005 |
| EILV (%TLC) | 94 (1) | 93 (1) | 94 (1) | 93 (1) | 0.242 |
| Petco2 (mm Hg) | 46.3 (1.4) | 44.9 (1.2) | 51.0 (1.4)*† | 48.2 (1.7)†‡ | <0.0005 |
| Paco2 (mm Hg) | 41.9 (1.1) | 40.8 (1.8) | 44.7 (1.1)† | 45.0 (1.9)*† | 0.109 |
| HCO3− (mmol/l) | 23.0 (0.5) | 22.1 (0.5)* | 24.2 (0.5)*† | 23.3 (0.5)† | 0.002 |
| pH | 7.36 (0.01) | 7.36 (0.02) | 7.36 (0.01) | 7.34 (0.02) | 0.636 |
| Base excess (mmol/l) | −1.94 (0.44) | −2.71 (0.63)* | −1.05 (0.46)†p = 0.09 v RA+PL | −2.25 (0.54) | 0.038 |