Exercise testing in patients with diaphragm paresis.

Bonnevie T, Gravier FE, Ducrocq A, Debeaumont D, Viacroze C,
Cuvelier A, Muir JF, Tardif C.

Respir Physiol Neurobiol. 2018 Jan;248:31-35.

PURPOSE: Diaphragm paresis (DP) is characterized by abnormalities of respiratory
muscle function. However, the impact of DP on exercise capacity is not well
known. This study was performed to assess exercise tolerance in patients with DP
and to determine whether inspiratory muscle function was related to exercise
capacity, ventilatory pattern and cardiovascular function during exercise.
METHODS: This retrospective study included patients with DP who underwent both
diaphragmatic force measurements, and cardiopulmonary exercise testing (CPET).
RESULTS: Fourteen patients were included. Dyspnea was the main symptom limiting
exertion (86%). Exercise capacity was slightly reduced (median VO2peak: 80%
[74.5%-90.5%]), mostly due to ventilatory limitation. Diaphragm and overall
inspiratory muscle function were correlated with exercise ventilation. Moreover,
overall inspiratory muscle function was related with oxygen consumption (r=0.61)
and maximal workload (r=0.68).
CONCLUSIONS: DP decreases aerobic capacity due to ventilatory limitation.
Diaphragm function is correlated with exercise ventilation whereas overall
inspiratory muscle function is correlated with both exercise capacity and
ventilation suggesting the importance of the accessory inspiratory muscles during
exercise for patients with DP. Further larger prospective studies are needed to
confirm these results.