RT Journal Article
SR Electronic
T1 Unilateral diaphragmatic paralysis: inspiratory muscles, breathlessness and exercise capacity
JF ERJ Open Research
JO erjor
FD European Respiratory Society
SP 00357-2019
DO 10.1183/23120541.00357-2019
VO 7
IS 1
A1 Mayra Caleffi Pereira
A1 Letícia Z. Cardenas
A1 Jeferson G. Ferreira
A1 Vinícius C. Iamonti
A1 Pauliane Vieira Santana
A1 André Apanavicius
A1 Pedro Caruso
A1 Angelo Fernandez
A1 Carlos R.R. de Carvalho
A1 Daniel Langer
A1 André L.P. de Albuquerque
YR 2021
UL http://openres.ersjournals.com/content/7/1/00357-2019.abstract
AB Background Patients with unilateral diaphragmatic paralysis (UDP) may present with dyspnoea without specific cause and limited ability to exercise. We aimed to investigate the diaphragm contraction mechanisms and nondiaphragmatic inspiratory muscle activation during exercise in patients with UDP, compared with healthy individuals.Methods Pulmonary function, as well as volitional and nonvolitional inspiratory muscle strength were evaluated in 35 patients and in 20 healthy subjects. Respiratory pressures and electromyography of scalene and sternocleidomastoid muscles were continuously recorded during incremental maximal cardiopulmonary exercise testing until symptom limitation. Dyspnoea was assessed at rest, every 2 min during exercise and at the end of exercise with a modified Borg scale.Main results Inspiratory muscle strength measurements were significantly lower for patients in comparison to controls (all p<0.05). Patients achieved lower peak of exercise (lower oxygen consumption) compared to controls, with both gastric (−9.8±4.6 cmH2O versus 8.9±6.0 cmH2O) and transdiaphragmatic (6.5±5.5 cmH2O versus 26.9±10.9 cmH2O) pressures significantly lower, along with larger activation of both scalene (40±22% EMGmax versus 18±14% EMGmax) and sternocleidomastoid (34±22% EMGmax versus 14±8% EMGmax). In addition, the paralysis group presented significant differences in breathing pattern during exercise (lower tidal volume and higher respiratory rate) with more dyspnoea symptoms compared to the control group.Conclusion The paralysis group presented with exercise limitation accompanied by impairment in transdiaphragmatic pressure generation and larger accessory inspiratory muscles activation compared to controls, thereby contributing to a neuromechanical dissociation and increased dyspnoea perception.The exercise capacity limitation in patients with unilateral diaphragmatic paralysis is characterised by an inefficient hemidiaphragm contraction. Consequently, there is a neuromechanical dissociation with an overload of inspiratory accessory muscles and higher breathlessness. https://bit.ly/2XxAR4K