Document Detail

Neural respiratory drive, pulmonary mechanics and breathlessness in patients with cystic fibrosis.
MedLine Citation:
PMID:  21285244     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Neural respiratory drive (NRD) measured from the diaphragm electromyogram (EMGdi) reflects the load/capacity balance of the respiratory muscle pump and is a marker of lung disease severity. EMGdi measurement is invasive, but recording the EMG from the parasternal intercostal muscles using surface electrodes (sEMGpara) could provide a non-invasive method of assessing NRD and disease severity. Objectives To test the hypothesis that NRD measured by sEMGpara correlates with EMGdi, to provide an index of disease severity in cystic fibrosis (CF) and to relate to exercise-induced breathlessness.
METHODS: 15 patients with CF (mean forced expiratory volume in 1 s (FEV(1)) 53.5% predicted) and 15 age-matched healthy controls were studied. sEMGpara and EMGdi were recorded at rest and during exercise. sEMGpara was recorded using surface electrodes and EMGdi using a multipair oesophageal electrode catheter. Signals were normalised using the peak EMG recorded during maximum respiratory manoeuvres and expressed as EMG%max. The respiratory pattern, metabolic data, oesophageal and gastric pressures and Borg scores were also recorded.
RESULTS: Mean (SD) resting sEMGpara%max and EMGdi%max were higher in patients with CF than in controls (13.1 (7)% and 18.5 (7.5)% vs 5.8 (3)% and 7.5 (2)%, respectively, p<0.001). In the patients with CF, resting sEMGpara%max and EMGdi%max were related to the degree of airways obstruction (FEV(1)) (r = -0.91 and r = -0.82, both p<0.001), hyperinflation (r = 0.63 and r = 0.56, both p<0.001) and dynamic lung compliance (r = -0.53 and r = -0.59, both p<0.001). During exercise, sEMGpara%max and EMGdi%max were strongly correlated with breathlessness in the patients with CF before (r = 0.906, p<0.001) and after (r = 0.975, p<0.001) the onset of neuromechanical dissociation.
CONCLUSION: sEMGpara%max provides a non-invasive marker of neural drive, which reflects disease severity and exercise-induced breathlessness in CF.
Charles C Reilly; Katie Ward; Caroline J Jolley; Alan C Lunt; Joerg Steier; Caroline Elston; Michael I Polkey; Gerrard F Rafferty; John Moxham
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-02-01
Journal Detail:
Title:  Thorax     Volume:  66     ISSN:  1468-3296     ISO Abbreviation:  Thorax     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-02-21     Completed Date:  2011-04-04     Revised Date:  2014-02-20    
Medline Journal Info:
Nlm Unique ID:  0417353     Medline TA:  Thorax     Country:  England    
Other Details:
Languages:  eng     Pagination:  240-6     Citation Subset:  IM    
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MeSH Terms
Cystic Fibrosis / complications*,  physiopathology*
Diaphragm / physiopathology
Dyspnea / etiology*,  physiopathology
Electromyography / methods
Exercise / physiology
Exercise Test / methods
Forced Expiratory Volume / physiology
Intercostal Muscles / physiopathology
Reproducibility of Results
Respiratory Mechanics / physiology*
Severity of Illness Index
Vital Capacity / physiology
Young Adult
Grant Support
G0500411//Medical Research Council; //Medical Research Council

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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