Studies using additional methods to assess the presence of a certain limitation to exercise
| Publication type | First author [ref.] (year) | Study population (n) | Study design | CPET method | Limitation(s) to exercise | Study methods | Results and conclusion |
|---|---|---|---|---|---|---|---|
| Research article | Markowitz [62] (2004) | Unexplained exertional dyspnoea and fatigue (130) | P | CE | Pulmonary vascular limitation (defined as pulmonary vascular resistance at maximum exercise >120 dynes⋅s⋅cm−5 and peak-exercise systemic oxygen delivery <80% predicted, without pulmonary mechanical limit (BR <11 L·min−1) or poor effort | Patients underwent invasive CPET with pulmonary and radial artery catheter | The combined use of VʹO2peak <58% pred, VʹO2 at AT <38% of VʹO2peak pred, maximal BR >8 L·min−1 and VʹE/VʹCO2 at AT >34 to identify pulmonary vascular limitation resulted in an accuracy of 85% with a sensitivity of 79% and a specificity of 88% |
| Research article | Chin [63] (2013) | Mild COPD (GOLD stage I) (20) versus age-matched healthy controls (20) | P | CE | Ventilatory limitation | Patients completed two symptom-limited incremental cycle exercise tests, in randomised order: unloaded control and added dead space of 0.6 L | Adding dead space resulted in achievement of significant (p<0.05) lower average maximal work rate while average peak ventilation did not significantly increase in both groups, providing evidence that the respiratory system reached or approached its limit under control conditions The average BR did not decline below 26% in the two groups without or with added dead space, but important mechanical constraints at peak exercise were present (inability to decrease EELV, a high EILV/TLC and a low IRV) |
AT: anaerobic threshold; BR: breathing reserve; CE: cycle ergometer; CPET: cardiopulmonary exercise testing; EELV: end expiratory lung volume; EILV: end inspiratory lung volume; GOLD: Global Initiative for Chronic Obstructive Lung Disease; IC: inspiratory capacity; IRV: inspiratory reserve volume; P: prospective; TLC: total lung capacity; VʹE/VʹCO2: minute ventilation/carbon dioxide production slope; VʹO2: oxygen uptake; VʹO2peak: peak oxygen uptake.