Document Detail

In normal subjects bracing impairs the function of the inspiratory muscles.
MedLine Citation:
PMID:  10414407     Owner:  NLM     Status:  MEDLINE    
Normal subjects can increase their capacity to sustain hyperpnoea by bracing their arms on fixed objects, a procedure which is also known to reduce dyspnoea in patients with chronic obstructive pulmonary disease (COPD). In the present study, it was tested whether bracing per se could improve the function of the diaphragm. The effect of bracing on diaphragm function was studied in six normal subjects by recording changes in oesophageal (delta Poes) and transdiaphragmatic (delta Pdi) pressure during inspiratory capacity (IC) manoeuvres in the seated and upright postures, and in the seated posture, also during bilateral phrenic nerve stimulation (BPNS) at functional residual capacity (FRC). The pattern of ribcage motion and deformation associated with bracing and with diaphragm contraction was also evaluated using inductance plethysmography and magnetometers. Bracing increased FRC by >300 mL and reduced IC by approximately 200 mL, in both postures. Delta Pdi during BPNS decreased on average by 15% indicating an impaired diaphragmatic function. The ribcage was deformed with bracing and was more distortable during BPNS. In conclusion, in normal subjects, bracing impairs the function of the inspiratory muscles and reduces ribcage stability. These negative effects cannot explain the improved capacity to sustain hyperpnoea when the arms are braced.
E Prandi; J Couture; F Bellemare
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The European respiratory journal     Volume:  13     ISSN:  0903-1936     ISO Abbreviation:  Eur. Respir. J.     Publication Date:  1999 May 
Date Detail:
Created Date:  1999-09-03     Completed Date:  1999-09-03     Revised Date:  2013-05-23    
Medline Journal Info:
Nlm Unique ID:  8803460     Medline TA:  Eur Respir J     Country:  DENMARK    
Other Details:
Languages:  eng     Pagination:  1078-85     Citation Subset:  IM    
Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Université de Montréal, Québec, Canada.
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MeSH Terms
Diaphragm / physiology*
Functional Residual Capacity
Muscle Contraction / physiology
Phrenic Nerve / physiology
Posture / physiology
Respiratory Function Tests
Respiratory Mechanics / physiology*
Ribs / physiology

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