Table 6

Association between Borg breathlessness scores and measured variables during exercise in 15 patients with cystic fibrosis following the onset of neuromechanical dissociation (70% of total exercise time to exhaustion)

ParameterSpearman (r)95% CIp Value
EMGdi%max0.9750.660 to 0.998<0.001
sEMGpara%max0.9750.660 to 0.998<0.001
V′o2/kg (ml.min.kg)0.9750.660 to 0.998<0.001
V′o2 (l/min)0.9750.660 to 0.998<0.001
V′co2 (l/min)0.9750.660 to 0.998<0.001
RER0.9750.660 to 0.998<0.001
MV (l/min)0.872−0.044 to 0.9910.053
PTPoes (cm H2O.s.l/min)0.872−0.044 to 0.9910.053
PTPdi (cm H2O.s.l/min)0.820−0.223 to 0.9880.886
TTI0.820−0.223 to 0.9880.886
Petco2 (mm Hg)−0.658−0.975 to 0.5350.227
IC (l)−0.410−0.949 to 0.7400.493
  • EMG, electromyogram; EMGdi%max, diaphragm EMG activity normalised to maximal evoked EMG during inspiratory manoeuvres; IC, inspiratory capacity; MV, minute ventilation; Petco2, end tidal carbon dioxide; PTPoes, oesophageal pressure time product; PTPdi, diaphragm pressure time product; RER, respiratory exchange ratio; sEMGpara%max, surface parasternal EMG activity normalised to maximal evoked EMG during inspiratory manoeuvres; TTI, tension time index; V′co2, carbon dioxide production; V′o2, oxygen uptake.