Table 4—

Maximal cardiopulmonary exercise testing in chronic obstructive pulmonary disease patients before and after treatment with sildenafil

BaselineAfter 3-month treatment with sildenafil
Workload max W56±28 (37±17)56±22 (39±27)
Peak V’O2 mL·kg−1·min−112.1±3.6 (44±11)12.4±3.8 (46±13)
Cardiac frequency max beats·min−1122±19 (79±11)124±14 (81±7)
Peak O2- pulse mL·beat−17.1±2 (50±18)7.4±1.4 (53±20)
VE max L·min−138±14 (67±16)39±15 (65±15)
VE/VCO2
  Slope46±2740±17
  At nadir51±1846±15
ΔVO2/Δworkload8.4±1.68.9±1.9
Pa,O2 mmHg
  At rest74±1372±14
  During exercise64±1764±19
Pa,CO2mmHg
  At rest39±636±12
  During exercise42±841±6
Sa,O2%
  At rest95±294±2
  During exercise89±688±6
6MWD m385±135396±116
Borg score6.4±1.76.6±2.2
  • Data are presented as mean±sd (% of predicted±sd) or mean±sd. Max: maximum; V’O2: oxygen uptake; VE: minute ventilation; VCO2: carbon dioxide production; ΔVO2/Δworkload: increase in VO2 with respect to increase in work rate; Pa,O2: arterial oxygen tension; Pa,CO2: carbon dioxide arterial tension; Sa,O2: arterial oxygen saturation; 6MWD: 6-min walk distance.