Reduction of total lung capacity in obese men: comparison of total intrathoracic and gas volumes

2.50
Hdl Handle:
http://hdl.handle.net/10547/594732
Title:
Reduction of total lung capacity in obese men: comparison of total intrathoracic and gas volumes
Authors:
Watson, R.A.; Pride, N.B.; Thomas, E.Louise; Fitzpatrick, Julie; Durighel, Giuliana; McCarthy, John; Morin, Stanislas X.; Ind, P.W.; Bell, Jimmy D. ( 0000-0003-3804-1281 )
Abstract:
Restriction of total lung capacity (TLC) is found in some obese subjects, but the mechanism is unclear. Two hypotheses are as follows: 1) increased abdominal volume prevents full descent of the diaphragm; and 2) increased intrathoracic fat reduces space for full lung expansion. We have measured total intrathoracic volume at full inflation using magnetic resonance imaging (MRI) in 14 asymptomatic obese men [mean age 52 yr, body mass index (BMI) 35–45 kg/m2] and 7 control men (mean age 50 yr, BMI 22–27 kg/m2). MRI volumes were compared with gas volumes at TLC. All measurements were made with subjects supine. Obese men had smaller functional residual capacity (FRC) and FRC-to-TLC ratio than control men. There was a 12% predicted difference in mean TLC between obese (84% predicted) and control men (96% predicted). In contrast, differences in total intrathoracic volume (MRI) at full inflation were only 4% predicted TLC (obese 116% predicted TLC, control 120% predicted TLC), because mediastinal volume was larger in obese than in control [heart and major vessels (obese 1.10 liter, control 0.87 liter, P = 0.016) and intrathoracic fat (obese 0.68 liter, control 0.23 liter, P < 0.0001)]. As a consequence of increased mediastinal volume, intrathoracic volume at FRC in obese men was considerably larger than indicated by the gas volume at FRC. The difference in gas volume at TLC between the six obese men with restriction, TLC < 80% predicted (OR), and the eight obese men with TLC > 80% predicted (ON) was 26% predicted TLC. Mediastinal volume was similar in OR (1.84 liter) and ON (1.73 liter), but total intrathoracic volume was 19% predicted TLC smaller in OR than in ON. We conclude that the major factor restricting TLC in some obese men was reduced thoracic expansion at full inflation.
Affiliation:
National Heart and Lung Institute; Imperial College London
Citation:
Watson, R.A. et al (2010) 'Reduction of total lung capacity in obese men: comparison of total intrathoracic and gas volumes'. Journal of Applied Physiology 108 (6):1605
Publisher:
American Physiological Society
Journal:
Journal of Applied Physiology
Issue Date:
18-Mar-2010
URI:
http://hdl.handle.net/10547/594732
DOI:
10.1152/japplphysiol.01267.2009
PubMed ID:
20299612
PubMed Central ID:
PMC2886677
Additional Links:
http://jap.physiology.org/cgi/doi/10.1152/japplphysiol.01267.2009
Type:
Article
Language:
en
ISSN:
8750-7587; 1522-1601
Appears in Collections:
Muscle Cellular and Molecular Physiology

Full metadata record

DC FieldValue Language
dc.contributor.authorWatson, R.A.en
dc.contributor.authorPride, N.B.en
dc.contributor.authorThomas, E.Louiseen
dc.contributor.authorFitzpatrick, Julieen
dc.contributor.authorDurighel, Giulianaen
dc.contributor.authorMcCarthy, Johnen
dc.contributor.authorMorin, Stanislas X.en
dc.contributor.authorInd, P.W.en
dc.contributor.authorBell, Jimmy D.en
dc.date.accessioned2016-01-25T10:31:54Zen
dc.date.available2016-01-25T10:31:54Zen
dc.date.issued2010-03-18en
dc.identifier.citationWatson, R.A. et al (2010) 'Reduction of total lung capacity in obese men: comparison of total intrathoracic and gas volumes'. Journal of Applied Physiology 108 (6):1605en
dc.identifier.issn8750-7587en
dc.identifier.issn1522-1601en
dc.identifier.pmid20299612en
dc.identifier.doi10.1152/japplphysiol.01267.2009en
dc.identifier.urihttp://hdl.handle.net/10547/594732en
dc.description.abstractRestriction of total lung capacity (TLC) is found in some obese subjects, but the mechanism is unclear. Two hypotheses are as follows: 1) increased abdominal volume prevents full descent of the diaphragm; and 2) increased intrathoracic fat reduces space for full lung expansion. We have measured total intrathoracic volume at full inflation using magnetic resonance imaging (MRI) in 14 asymptomatic obese men [mean age 52 yr, body mass index (BMI) 35–45 kg/m2] and 7 control men (mean age 50 yr, BMI 22–27 kg/m2). MRI volumes were compared with gas volumes at TLC. All measurements were made with subjects supine. Obese men had smaller functional residual capacity (FRC) and FRC-to-TLC ratio than control men. There was a 12% predicted difference in mean TLC between obese (84% predicted) and control men (96% predicted). In contrast, differences in total intrathoracic volume (MRI) at full inflation were only 4% predicted TLC (obese 116% predicted TLC, control 120% predicted TLC), because mediastinal volume was larger in obese than in control [heart and major vessels (obese 1.10 liter, control 0.87 liter, P = 0.016) and intrathoracic fat (obese 0.68 liter, control 0.23 liter, P < 0.0001)]. As a consequence of increased mediastinal volume, intrathoracic volume at FRC in obese men was considerably larger than indicated by the gas volume at FRC. The difference in gas volume at TLC between the six obese men with restriction, TLC < 80% predicted (OR), and the eight obese men with TLC > 80% predicted (ON) was 26% predicted TLC. Mediastinal volume was similar in OR (1.84 liter) and ON (1.73 liter), but total intrathoracic volume was 19% predicted TLC smaller in OR than in ON. We conclude that the major factor restricting TLC in some obese men was reduced thoracic expansion at full inflation.en
dc.language.isoenen
dc.publisherAmerican Physiological Societyen
dc.relation.urlhttp://jap.physiology.org/cgi/doi/10.1152/japplphysiol.01267.2009en
dc.subjectmagnetic resonance imagingen
dc.subjectrestricted total lung capacityen
dc.subjectlung capacityen
dc.subjectmediastinal volumeen
dc.subjectMRIen
dc.titleReduction of total lung capacity in obese men: comparison of total intrathoracic and gas volumesen
dc.typeArticleen
dc.contributor.departmentNational Heart and Lung Instituteen
dc.contributor.departmentImperial College Londonen
dc.identifier.journalJournal of Applied Physiologyen
dc.identifier.pmcidPMC2886677en

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