Table 3 Post-dose cardiorespiratory and perceptual responses at the highest equivalent isotime and at the symptom-limited peak of constant work rate exercise at 75% Wmax (53 (4) Watts)
IsotimePeak
PlaceboFurosemidePlaceboFurosemide
Time (min)10.2 (8.7)10.2 (8.7)10.9 (9.0)12.6 (10.0)*
Dyspnoea (Borg)4.9 (2.1)4.1 (2.2)†5.2 (2.2)5.2 (2.6)
Leg discomfort (Borg)5.6 (2.5)5.0 (2.6)6.3 (2.7)6.3 (2.4)
HR (beats/min)115 (21)115 (19)116 (19)116 (19)
O2 pulse (ml/beat)9.5 (3.1)9.9 (3.7)9.7 (3.2)10.2 (3.1)*
V̇o2 (ml/kg/min)13.6 (3.8)14.1 (3.7)14.0 (3.7)14.8 (3.3)*
V̇co2 (ml/kg/min)13.2 (4.1)14.0 (4.2)*13.9 (4.0)14.8 (3.7)*
VE (l/min)34.8 (10.2)36.2 (11.9)36.1 (10.3)37.9 (10.5)*
Vt (l)1.17 (0.30)1.24 (0.33)*1.18 (0.30)1.24 (0.31)
fR (breaths/min)30.5 (7.8)29.6 (7.4)31.4 (8.1)31.2 (7.2)
Ti (s)0.79 (0.20)0.82 (0.19)0.78 (0.20)0.77 (0.18)
Te (s)1.29 (0.32)1.30 (0.31)1.28 (0.34)1.27 (0.28)
Ti/Ttot (%)38.0 (4.1)38.4 (4.0)*38.6 (5.4)38.4 (4.2)
Vt/Ti (l/s)1.53 (0.46)1.56 (0.48)1.58 (0.47)1.65 (0.42)
Vt/Te (l/s)0.94 (0.29)1.00 (0.34)*0.96 (0.29)1.01 (0.30)*
IC (l)1.78 (0.46)1.90 (0.45)*1.76 (0.43)1.84 (0.47)
ΔIC from rest (l)−0.61 (0.38)−0.60 (0.47)−0.61 (0.42)−0.65 (0.44)
IRV (l)0.61 (0.30)0.66 (0.29)0.58 (0.27)0.61 (0.32)
Petco2 (mm Hg)37.6 (3.7)38.4 (4.2)37.7 (4.2)38.0 (4.5)
Spo2 (%)93.6 (2.5)93.8 (2.9)93.6 (2.7)93.6 (3.0)

  • Values are mean (SD).

  • fR, breathing frequency; HR, heart rate; IC, inspiratory capacity; ΔIC, change in IC from rest (ie, extent of dynamic hyperinflation); IRV, inspiratory reserve volume; Petco2, partial pressure of end tidal CO2; Spo2, oxygen saturation measured by pulse oximetry; Te, expiratory time; Ti, inspiratory tine; Ti/Ttot, inspiratory duty cycle; Ttot, total time; V̇co2, carbon dioxide production; VE, minute ventilation; V̇o2, oxygen uptake; Vt, tidal volume; Vt/Te, mean expiratory tidal flow; Vt/Ti, mean inspiratory tidal flow.

  • *p<0.05, †p<0.01 furosemide vs placebo at same stage of exercise.