Document Detail


Effect of severe isolated unilateral and bilateral diaphragm weakness on exercise performance.
MedLine Citation:
PMID:  11991876     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Patients with isolated diaphragm paralysis depend on recruitment of extradiaphragmatic respiratory muscles to increase ventilation, but little is known about exercise performance or the response of the inspiratory muscles to loaded breathing. By convention, unilateral diaphragm paralysis is regarded as a trivial condition whereas bilateral paralysis is considered to be potentially life-threatening. In fact, no data exist concerning exercise performance under these conditions. We studied incremental treadmill exercise performed by eight patients with bilateral diaphragm paralysis, eight patients with unilateral diaphragm paralysis, and eight age-matched control subjects. Respiratory muscle endurance (RME) was also measured by an inspiratory threshold loading method. Exercise time, compared with control subjects (671 seconds), was moderately reduced in unilateral diaphragm paralysis (512 seconds, p = 0.07) and further reduced in bilateral diaphragm paralysis (456 seconds, p = 0.02). Similarly, peak minute ventilation was lower in patients with unilateral diaphragm paralysis (84 L x min(-1), p = 0.01) and in patients with bilateral diaphragm paralysis (69 L x min(-1), p = 0.001) compared with control subjects (114 L x min(-1)). However, patients with unilateral diaphragm paralysis and patients with bilateral diaphragm paralysis had increased ratios of peak oxygen consumption to peak minute ventilation compared with control subjects (p = 0.0007 and p < 0.0001, respectively). Nine patients had normal RME; exercise time was moderately increased in these patients (502 seconds) compared with seven patients with reduced RME (461 seconds). In conclusion, although exercise performance is impaired in bilateral diaphragm paralysis, these patients can sustain a reasonable exercise load, particularly if RME is preserved and compensatory mechanisms have developed. In addition, exercise tolerance is diminished in patients with unilateral diaphragm paralysis.
Authors:
Nicholas Hart; Annabel H Nickol; Derek Cramer; Simon P Ward; Frédéric Lofaso; Neil B Pride; John Moxham; Michael I Polkey
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of respiratory and critical care medicine     Volume:  165     ISSN:  1073-449X     ISO Abbreviation:  Am. J. Respir. Crit. Care Med.     Publication Date:  2002 May 
Date Detail:
Created Date:  2002-05-06     Completed Date:  2002-06-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9421642     Medline TA:  Am J Respir Crit Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1265-70     Citation Subset:  AIM; IM    
Affiliation:
Respiratory Muscle Laboratory and Lung Function Unit, Royal Brompton Hospital, London, United Kingdom. drnhart@aol.com
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Analysis of Variance
Case-Control Studies
Exercise*
Humans
Male
Middle Aged
Physical Endurance
Respiratory Mechanics
Respiratory Muscles / physiopathology
Respiratory Paralysis / physiopathology*

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


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