| Unventilated airway is time-dependently constricted in paralyzed dogs. | |
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MedLine Citation:
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PMID: 11748409 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Apnea has been reported to produce bronchoconstriction and to cause hypoxia, hypercapnia, and modulation of vagal afferent nerves, which also change airway tone. In this study, the authors determined the mechanism of apnea-induced bronchoconstriction. METHODS: Twenty-eight dogs anesthetized and paralyzed were assigned to four groups (n = 7 each): apnea after artificial ventilation with 50% and 100% O2 groups (apnea-50% O2 and apnea-100% O2 groups, respectively), an apnea plus vagotomy group (fraction of inspired oxygen [FiO2] = 1.0), and a one-lung ventilation group (FiO2 = 1.0). The trachea was intubated with a single- or double-lumen tube in the three apnea groups or the one-lung ventilation group, respectively. The bronchial cross-sectional area (BCA) was assessed by the authors' bronchoscopic method. In the apnea-100% O2 and apnea plus vagotomy groups, a respirator was turned off for 5 min to produce apnea. In the apnea-50% O2 group, apnea was produced for 3 min. In the one-lung ventilation group, the right lumen was blocked for 5 min, and 15 min later, the left lumen was blocked for 5 min. BCA, arterial oxygen tension (PaO2), and arterial carbon dioxide tension (PaCO2) were assessed every minute. RESULTS: The BCA in intact dogs time-dependently decreased by approximately 20% and 40% at 3 and 5 min after apnea started, respectively, whereas they did not in vagotomized dogs. In the apnea-50% O2 and apnea-100% O2 groups, bronchoconstriction could occur without hypoxemia, although hypercapnia was observed in all dogs. In the one-lung ventilation group, despite the fact that PaCO2 increased by only 2 mmHg without hypoxemia, unventilated BCA time-dependently decreased by 33.6 +/- 10.3%, whereas ventilated BCA did not. CONCLUSION: The current study suggests that the unventilated airway may constrict spontaneously. In addition, the airway constriction could be vagally mediated but not due to hypoxia and hypercapnia. |
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Authors:
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K Hirota; E Hashiba; S Kabara; H Yoshioka; H Ishihara; A Matsuki |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Anesthesiology Volume: 95 ISSN: 0003-3022 ISO Abbreviation: Anesthesiology Publication Date: 2001 Dec |
Date Detail:
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Created Date: 2001-12-18 Completed Date: 2002-01-07 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 1300217 Medline TA: Anesthesiology Country: United States |
Other Details:
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Languages: eng Pagination: 1480-4 Citation Subset: AIM; IM |
Affiliation:
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Department of Anesthesiology, University of Hirosaki School of Medicine, Japan. masuika@cc.hirosaki-u.ac.jp |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Apnea / physiopathology Blood Gas Analysis Bronchi / pathology, physiopathology Carbon Dioxide / blood Constriction, Pathologic / pathology, physiopathology* Dogs Hydrogen-Ion Concentration Oxygen / blood Paralysis / pathology, physiopathology* Respiratory Mechanics / physiology Vagotomy |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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