Chronicle obstructive pulmonary disease is a worldwide cause of mortality and morbidity.
This systemic disease progressively leads to dyspnea, muscle wasting and exercise
capacity impairment.
Pulmonary rehabilitation is a cornerstone in the management of these systemic effects.
Unfortunately, access to pulmonary rehabilitation is limited for many people who would
benefit from it, primarily because of a lack of pulmonary rehabilitation and assessment
centers. Optimal assessment should include an incremental cardiopulmonary exercise
testing. This test allows to evaluate the factors contributing to exercise intolerance by
linking performance and physiological parameters to the underlying metabolism. Moreover,
it is the standard test to determine both the optimal training settings as well as any
cardiopulmonary contraindications to pulmonary rehabilitation. However, this test is not
available in most centers and when it is, consultations are limited. Therefore, pulmonary
rehabilitation is often delayed for several weeks and patients can lose motivation.
In order to promote pulmonary rehabilitation, the incremental cardiopulmonary exercise
testing could be replaced by field tests to individualize pulmonary rehabilitation
prescription.
The six-minute stepper test is a new field tool. Its sensitivity and reproducibility have
previously been reported in patients with chronicle obstructive pulmonary disease. It is
easy to set up in the clinical setting and could be used to individualize pulmonary
rehabilitation.
The main drawback when using field test is that they only provide a non specific
assessement of the functional capacity because cardiopulmonary parameters and gaz
exchanges are not monitored.
Although the performance during the 6-minute stepper test is moderately related with the
maximal oxygen consumption during the incremental cardiopulmonary exercise testing
performed on a cycloergometer, a direct comprehensive comparison of cardiopulmonary
parameters and gaz exchanges during these two tests have never been performed.
Moreover, stepping is more closely related with activities of daily life (requiring a
repetitive transition from rest to submaximal exercise intensity) than the maximal
incremental exercise on cycloergometer and could provide further insight on the
disability of patients during their usual activities, such as stair climbing (which is
frequently avoided). Additionally, on-transient phase two oxygen consumption kinetic is
particularly relevant because it evaluation is independent of the patient's motivation or
criteria used to terminate exercise.
Therefore, the aim of this study is to compare the cardiorespiratory parameters, the gaz
exchanges and the maximality between the six-minute stepper test and the incremental
cardiopulmonary exercise testing performed on a cycloergometer.
The secondary objective was to compare the on-transient oxygen consumption phase two
kinetic parameters (time constant, span and steady state) according to the severity of
the disease.