Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1993-12-20
pubmed:abstractText
Continuous negative airway pressure (CNAP) causes a decrease in lung volume, which is known to increase upper airway resistance by itself. We studied how this lung volume change could modify upper airway collapsibility with five normal awake subjects. In a first trial, pressure in a nasal mask (Pm) was progressively decreased in 3- to 5-cmH2O steps (CNAP). In a second trial, changes in lung volumes resulting from CNAP were prevented by applying simultaneously an equivalent level of negative extrathoracic pressure into a poncho-type respirator [isovolumetric CNAP (CNAPisovol)]. For each trial, we examined the relationship between the maximal inspiratory airflow of each flow-limited inspiratory cycle and the corresponding Pm by least-squares linear regression analysis and determined the critical pressure. We also determined the Pm threshold corresponding to the first Pm value below which flow limitation occurred. Flow limitation was observed in each subject with CNAP but in only two subjects with CNAPisovol. In these two subjects, the Pm threshold values were -20 and -9 cmH2O with CNAP and -39 and -16 cmH2O with CNAPisovol, respectively. Critical pressures for the same two subjects were -161 and -96 cmH2O with CNAP and -202 and -197 cmH2O with CNAPisovol, respectively. We conclude that CNAP-induced decreases in lung volume increase upper airway collapsibility.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
8750-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
75
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1222-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Effects of continuous negative airway pressure-related lung deflation on upper airway collapsibility.
pubmed:affiliation
Unité de Recherche, Centre de Pneumologie de l'Hôpital Laval, Université Laval, Quebec, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't