Document Detail

Effect of severe isolated unilateral and bilateral diaphragm weakness on exercise performance.
MedLine Citation:
PMID:  11991876     Owner:  NLM     Status:  MEDLINE    
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.
Nicholas Hart; Annabel H Nickol; Derek Cramer; Simon P Ward; Frédéric Lofaso; Neil B Pride; John Moxham; Michael I Polkey
Related Documents :
7956406 - Inaccuracy of noninvasive estimates of vd/vt in clinical exercise testing.
17497586 - Ventilatory and lactic thresholds in subjects with sickle cell trait.
9282236 - Influence of inspiratory capacity on bronchodilatation via turbuhaler or pressurized me...
14758156 - Proportional-assist ventilation compared with pressure-support ventilation during exerc...
7559216 - Effect of unweighting on skeletal muscle use during exercise.
7039416 - Oxygenation during high-frequency ventilation compared with conventional mechanical ven...
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    
Respiratory Muscle Laboratory and Lung Function Unit, Royal Brompton Hospital, London, United Kingdom.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Analysis of Variance
Case-Control Studies
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

Previous Document:  Dyspnea and decreased variability of breathing in patients with restrictive lung disease.
Next Document:  ARDSNet lower tidal volume ventilatory strategy may generate intrinsic positive end-expiratory press...