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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1998-11-20
pubmed:abstractText
The effect of stimulus frequency on the in vivo pressure generating capacity of the human diaphragm is unknown at lung volumes other than functional residual capacity. The transdiaphragmatic pressure (Pdi) produced by a pair of phrenic nerve stimuli may be viewed as the sum of the Pdi elicited by the first (T1 Pdi) and second (T2 Pdi) stimuli. We used bilateral anterior supramaximal magnetic phrenic nerve stimulation and a digital subtraction technique to obtain the T2 Pdi at interstimulus intervals of 999, 100, 50, 33, and 10 ms in eight normal subjects at lung volumes between residual volume and total lung capacity. The reduction in T2 Pdi that we observed as lung volume increased was greatest at long interstimulus intervals, whereas the T2 Pdi obtained with short interstimulus intervals remained relatively stable over the 50% of vital capacity around functional residual capacity. For all interstimulus intervals, the total pressure produced by the pair decreased as a function of increasing lung volume. These data demonstrate that, in the human diaphragm, hyperinflation has a disproportionately severe effect on the summation of pressure responses elicited by low-frequency stimulations; this effect is distinct from and additional to the known length-tension relationship.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
8750-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
85
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1322-8
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Influence of acute lung volume change on contractile properties of human diaphragm.
pubmed:affiliation
Respiratory Muscle Laboratory, King's College School of Medicine and Dentistry, London SE5 9PJ, United Kingdom. michael.polkey@kcl.ac.uk
pubmed:publicationType
Journal Article