Document Detail


The contribution of chemoreflex drives to resting breathing in man.
MedLine Citation:
PMID:  11429624     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The contribution of automatic drives to breathing at rest, relative to behavioural drives such as "wakefulness", has been a subject of debate. We measured the combined central and peripheral chemoreflex contribution to resting ventilation using a modified rebreathing method that included a prior hyperventilation and addition of oxygen to maintain isoxia at a P(ET,O2) (end-tidal partial pressure of oxygen) of 100 mmHg. During rebreathing, ventilation was unrelated to P(ET,CO2) (end-tidal partial pressure of carbon dioxide) in the hypocapnic range, but after a threshold P(ET,CO2) was exceeded, ventilation increased linearly with P(ET,CO2). We considered the sub-threshold ventilation to be an estimate of the behavioural drives to breathe (mean +/- S.E.M. = 3.1 +/- 0.5 l min(-1)), and compared it to ventilation at rest (mean +/- S.E.M. = 9.1 +/- 0.7 l min(-1)). The difference was significant (Student's paired t test, P < 0.001). We also considered the threshold P(CO2) observed during rebreathing to be an estimate of the chemoreflex threshold at rest (mean +/- S.E.M. = 42.0 +/- 0.5 mmHg). However, P(ET,CO2) during rebreathing estimates mixed venous or tissue P(CO2), whereas the resting P(ET,CO2) during resting breathing estimates P(a,CO2) (arterial partial pressure of carbon dioxide). The chemoreflex threshold measured during rebreathing was therefore reduced by the difference in P(ET,CO2) at rest and at the start of rebreathing (the plateau estimates the mixed venous P(CO2) at rest) in order to make comparisons. The corrected chemoreflex thresholds (mean +/- S.E.M. = 26.0 +/- 0.9 mmHg) were significantly less (paired Student's t test, P < 0.001) than the resting P(ET,CO2) values (mean +/- S.E.M. = 34.3 +/- 0.5 mmHg). We conclude that both the behavioural and chemoreflex drives contribute to resting ventilation. Experimental Physiology (2001) 86.1, 109-116.
Authors:
S Mahamed; A F Ali; D Ho; B Wang; J Duffin
Related Documents :
1836824 - Hypercarbia is not the determinant factor of systemic arterial hypertension during carb...
9062614 - The detection of carbon dioxide embolism during laparoscopy in pigs: a comparison of tr...
3080014 - Carbon dioxide clearance and deadspace during high frequency jet ventilation. investiga...
10987394 - Intraoperative evaluation of laparoscopic insufflation technique for quality control in...
7016364 - Responses of pulmonary allograft and cheek pouch arterioles in the hamster to alteratio...
15785804 - Prediction of vapour pressure using descriptors derived from molecular dynamics.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental physiology     Volume:  86     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2001 Jan 
Date Detail:
Created Date:  2001-06-28     Completed Date:  2001-08-09     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  109-16     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adult
Behavior / physiology
Carbon Dioxide
Chemoreceptor Cells / physiology*
Differential Threshold
Female
Humans
Male
Oxygen
Partial Pressure
Reflex / physiology*
Respiratory Physiological Phenomena
Rest
Tidal Volume
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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


Previous Document:  Effects of exposure to high temperature and feeding level on regional blood flow and oxidative capac...
Next Document:  Dynamic ventilatory response to acute isocapnic hypoxia in septuagenarians.