Table 4– Physiological and perceptual responses to cardiopulmonary exercise testing in pulmonary arterial hypertension (PAH) patients who developed dynamic lung hyperinflation during exercise (PAH-H) and those who did not (PAH-NH)
Restiso-WR 1iso-WR 2Peak
PAH-HPAH-NHPAH-HPAH-NHPAH-HPAH-NHPAH-HPAH-NH
WR W20±020±060±060±090±2598±28
VO2 L·min−1 (% pred)0.26±0.03 (14±5)0.26±0.03 (13±5)0.43±0.08 (22±8)0.49±0.17 (24±10)0.78±0.09 (40±13)0.81±0.20 (40±14)1.25±0.25 (63±18)1.30±0.40 (61±16)
VO2 per kg−13.8±0.74.2±0.96.2±1.27.9±2.911.1±1.312.9±3.117.8±3.020.4±5.3
VCO2 L·min−10.22±0.020.23±0.020.33±0.070.38±0.100.80±0.090.81±0.151.42±0.291.50±0.48
VE L·min−111.3±2.211.6±2.219.0±3.118.7±3.337.7±7.435.1±7.967.5±17.567.9±22.4
VE % MVC12±311±321±618±741±1534±1671±1562±20
fR breaths·min−115±315±521±520±429±726±737±734±7
VT L0.80±0.200.80±0.180.92±0.230.99±0.211.33±0.281.42±0.321.89±0.462.02±0.50
VT/IC %31±634±835±939±1262±1454±1790±9*72±11
IC L2.6±0.72.5±0.62.7±0.72.6±0.62.3±0.72.7±0.72.1±0.7*2.8±0.7
IC/TLC %50±5*44±352±547±443±6*49±340±6*51±4
IRV L1.8±0.61.7±0.61.8±0.61.6±0.70.9±0.61.3±0.80.2±0.3*0.8±0.5
IRV/TLC %34±629±634±729±817±823±94±5*14±6
Dyspnoea Borg units0.0±0.00.0±0.00.6±0.30.4±0.24.3±1.4*2.0±0.87.9±0.9*5.2±1.6
Leg discomfort Borg units0.0±0.00.0±0.00.6±0.50.8±0.63.9±2.03.8±2.46.3±1.87.1±1.9
Pa,O2 mmHg82.3±8.686.0±12.577.2±12.979.0±17.7
Pa,CO2 mmHg32.3±4.133.6±5.229.8±3.731.5±5.2
PET,CO2 mmHg28±429±428±430±527±529±825±526±7
P(a–ET)CO2 mmHg4.8±2.24.2±3.44.9±2.45.0±3.9
VD/VT0.43±0.080.43±0.090.39±0.060.37±0.09
  • Data are presented as mean±sd. iso-WR 1: common standardised exercise work-rate (WR) of 20 W; iso-WR 2: common standardised exercise WR of 60 W; VO2: oxygen uptake; % pred: % predicted; VCO2: carbon dioxide production; VE: minute ventilation; MVC: maximal ventilatory capacity; fR: respiratory frequency; VT: tidal volume; IC: inspiratory capacity; TLC: total lung capacity; IRV: inspiratory reserve volume; Pa,O2: arterial oxygen tension; Pa,CO2: arterial carbon dioxide tension; PET,CO2: end-tidal carbon dioxide tension; P(a–ET)CO2: the gradient between arterial and end-tidal carbon dioxide tension; VD: physiological dead space. *: p<0.05, PAH-H versus PAH-NH at the same measurement point.