| Ventilatory response to 8 h of isocapnic and poikilocapnic hypoxia in humans. | |
| | |
MedLine Citation:
|
PMID: 7775303 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Almost all studies of the effects of prolonged hypoxia on ventilation (VE) in humans have been performed with the end-tidal PCO2 (PETCO2) left uncontrolled. The purpose of this study was to compare the effects of 8 h of hypoxia with PETCO2 held constant with 8 h of hypoxia with PETCO2 left uncontrolled. Ten subjects completed the study. Each was seated inside a chamber in which the inspired gas could be controlled so as to maintain the desired partial pressures of end-tidal gases (sampled via nasal catheter) constant (see L.S.G.E. Howard et al. J. Appl. Physiol. 78:1088-1091, 1995.). Three 8-h protocols were employed: 1) isocapnic hypoxia, at an end-tidal PO2 of 55 Torr with PETCO2 held at the subject's resting value; 2) poikilocapnic hypoxia, at the same end-tidal PO2; and 3) control, where the inspired gas was air. VE was measured (over 3 min) at 0 and 20 min and at hourly intervals between 1.5 and 7.5 h. There was a rise in VE during isocapnic hypoxia [from an initial VE of 16.2 +/- 1.3 (SE) l/min to a final VE of 24.8 +/- 1.6 l/min], which was significant compared with poikilocapnic hypoxia and control values (P < 0.001, analysis of variance). There was no significant progressive rise in VE during poikilocapnic hypoxia compared with control values. These results show that isocapnic hypoxia produces a progressive increase in VE when sustained over an 8-h period. The onset of this response is faster than has been noted in studies of the progressive rise in VE associated with the poikilocapnic hypoxia of altitude. |
| | |
Authors:
|
L S Howard; P A Robbins |
Related Documents
:
|
8442773 - The effect of hypoxia and acidosis on propranolol clearance in the isolated perfused ra... 8964753 - Predominant role of peripheral chemoreceptors in the termination of apnea in maturing n... 6696343 - Exercise testing in the evaluation of the patient with chronic cardiac failure. |
Publication Detail:
|
Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 78 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1995 Mar |
Date Detail:
|
Created Date: 1995-07-11 Completed Date: 1995-07-11 Revised Date: 2009-09-29 |
Medline Journal Info:
|
Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 1092-7 Citation Subset: IM |
Affiliation:
|
University of Oxford, University Laboratory of Physiology, United Kingdom. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adaptation, Physiological Adolescent Adult Anoxia / physiopathology* Female Humans Hypocapnia / physiopathology* Male Respiration* Tidal Volume Time Factors |
| Grant Support | |
ID/Acronym/Agency:
|
//Wellcome Trust |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Chamber for controlling end-tidal gas tensions over sustained periods in humans.
Next Document: Alterations in respiratory control during 8 h of isocapnic and poikilocapnic hypoxia in humans.