Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1983-5-27
pubmed:abstractText
To determine the influence of mouthpiece breathing on respiratory responses to sulfur dioxide (SO2), 23 young adult asthmatic volunteers were exposed in a chamber to 0.75 ppm SO2 during heavy exercise, once with breathing unencumbered and once while they wore noseclips and mouthpieces. These conditions (more severe than in typical ambient exposures) were deliberately chosen to produce significant physiological and clinical responses. Similar exposures to clean air served as controls. Exposure studies were separated by 1-week intervals and order was randomized. The protocol consisted of 10 min on a bicycle ergometer (mean load 650 kg-m/min, mean ventilation 40 liter/min), preceded and followed by response testing (body plethysmography, symptom questionnaires, and forced expiratory function tests; the last were performed only postexposure). During clean-air exposures, specific airway resistance (SRaw) and symptoms increased significantly, but no meaningful differences between mouthpiece breathing and unencumbered breathing were observed. Exposures to SO2 under these relatively severe conditions produced greater increases in SRaw than clean-air exposures regardless of the mode of breathing, but the excess increase was significantly greater with mouthpiece than with unencumbered breathing. Symptom changes and postexposure forced expiratory function showed qualitatively the same pattern of decrements with SO2 ad did SRaw, but the excess responses attributable to mouthpiece breathing did not attain statistical significance. Mouthpiece breathing can compromise upper-respiratory defenses against SO2 to the extent that responses are greater than with more natural breathing. The mode of breathing should be taken in account when applying laboratory human exposure data to air-quality risk assessment.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0013-9351
pubmed:author
pubmed:issnType
Print
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
340-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Respiratory effects of 0.75 ppm sulfur dioxide in exercising asthmatics: influence of upper-respiratory defenses.
pubmed:publicationType
Journal Article, Clinical Trial, Controlled Clinical Trial, Research Support, Non-U.S. Gov't