Document Detail


Ventilatory sensitivity to single breaths of CO2 around the control point in man.
MedLine Citation:
PMID:  7777703     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We used single inspiratory capacity breaths of 5, 6 or 8% CO2 in air to obtain ventilatory responses in normal subjects, with ensemble averaging of repeated runs to define stimulus and response (Protocol 1). We also compared the effect of an inspiratory capacity (IC) breath of 8% CO2 with that of two tidal volumes (TV) at the same concentration (Protocol 2). The ventilatory response was defined first as the ratio of peak changes in ventilation and end-tidal PCO2, and secondly by the ratio of their integrals. We obtained group mean values of 0.21 L min-1 mmHg-1 for the peak method and 0.80 L min-1 mmHg-1 for integrals (Protocol 1). There was no significant difference between IC and TV response values (Protocol 2) either by the peak method (0.17 vs 0.19 L min-1 mmHg-1) or by integrals (0.47 vs 0.53 L min-1 mmHg-1). A significant decrease in ventilation was seen in the second tidal volume 8% CO2 breath, even though the stimulus was unperceived by four out of five subjects. CO2 responses can be obtained from these techniques, but the necessary analysis is too cumbersome for general use. Taking a deep breath had no detectable separate effect, but CO2 in the airway may depress ventilation even at concentrations which the subject cannot detect.
Authors:
S S Fernando; K B Saunders
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Respiration physiology     Volume:  99     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  1995 Feb 
Date Detail:
Created Date:  1995-07-07     Completed Date:  1995-07-07     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  205-14     Citation Subset:  IM    
Affiliation:
Department of Medicine, St. George's Hospital Medical School, London, UK.
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MeSH Terms
Descriptor/Qualifier:
Administration, Inhalation
Adult
Carbon Dioxide / administration & dosage*
Female
Humans
Male
Mass Spectrometry
Respiration / drug effects,  physiology*
Respiratory Function Tests
Sensitivity and Specificity
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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