Document Detail


Inspiratory muscle relaxation rate after voluntary maximal isocapnic ventilation in humans.
MedLine Citation:
PMID:  1907603     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have investigated whether the capacity of the inspiratory muscles to generate pressure and flow during a ventilatory load is related to changes in inspiratory muscle relaxation rate. Five highly motivated normal subjects performed voluntary maximal isocapnic ventilation (MIV) for 2 min. Minute ventilation and esophageal, gastric, and transdiaphragmatic pressures were measured breath by breath. We observed that ventilation, peak inspiratory and expiratory pressures, and inspiratory flow rate declined from the start of the run to reach a plateau at 60 s that was sustained for the remainder of the exercise. In a subsequent series of studies, MIV was performed for variable durations between 15 and 120 s. The normalized maximum relaxation rate of unoccluded inspiratory sniffs (sniff MRR, %pressure loss/10 ms) was determined immediately on stopping MIV. Sniff MRR slowed as the duration of MIV increased and paralleled the decline in inspiratory pressure and ventilation observed during the 2-min exercise. No further slowing in MRR occurred when ventilation became sustainable. We conclude that, during MIV, the progressive loss of ventilation and capacity to generate pressure is associated with the early onset and progression of a peripheral fatiguing process within the inspiratory muscles.
Authors:
D A Mulvey; N G Koulouris; M W Elliott; C M Laroche; J Moxham; M Green
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  70     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1991 May 
Date Detail:
Created Date:  1991-09-09     Completed Date:  1991-09-09     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:  2173-80     Citation Subset:  IM    
Affiliation:
Respiratory Muscle Laboratory, Brompton Hospital, London, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Adult
Carbon Dioxide
Electric Stimulation
Fatigue / physiopathology
Female
Humans
Male
Muscle Relaxation / physiology
Phrenic Nerve / physiology
Pressure
Respiratory Mechanics / physiology*
Respiratory Muscles / physiology*
Chemical
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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