Document Detail

Control of breathing patterns and abdominal muscles during graded loads and tilt.
MedLine Citation:
PMID:  7928873     Owner:  NLM     Status:  MEDLINE    
Tilting from supine to upright purportedly enhances both segmental and pulmonary proprioceptive feedback, whereas an expiratory threshold load (ETL) preferentially enhances pulmonary feedback. To test this we studied 13 adults when supine and 60 degrees and 90 degrees head up. We measured tidal volume, inspiratory duration (TI), and expiratory duration (TE) from flow; estimated end-expiratory lung volume from inspiratory capacity; and determined burst amplitudes and durations from abdominal electromyograms (EMGs). ETLs were incremented from 0 (control) to 25 cmH2O in 5-cmH2O steps. Tidal volume was significantly increased by ETL but was unaffected by body position. Every load prolonged TE, whereas TI remained unchanged. When subjects were supine, abdominal EMGs were silent but became tonically active when subjects were upright. During ETL, abdominal activity became rhythmical and phase locked to expiration. Bursts amplitudes were enhanced with each increment in ETL, but burst durations did not change even though TE was prolonged. The altered breathing pattern and active expiration augmented inspiratory flow and decreased end-tidal PCO2. Responses were greatest when subjects were 90 degrees head up. The load-related increments in abdominal recruitment, with no change in burst durations, fit the concept of two central pattern generators: one controlling pattern and the other controlling rhythm of the central respiratory drive.
J Barrett; F Cerny; J A Hirsch; B Bishop
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  76     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1994 Jun 
Date Detail:
Created Date:  1994-11-01     Completed Date:  1994-11-01     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2473-80     Citation Subset:  IM; S    
Department of Physiology, State University of New York at Buffalo, 14214.
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MeSH Terms
Abdominal Muscles / physiology*
Carbon Dioxide / blood
Feedback / physiology
Middle Aged
Pleura / physiology
Proprioception / physiology*
Pulmonary Stretch Receptors / physiology
Respiratory Function Tests
Respiratory Mechanics / physiology*
Stomach / physiology
Tidal Volume / physiology
Vagus Nerve / physiology
Reg. No./Substance:
124-38-9/Carbon Dioxide

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

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