Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1983-4-15
pubmed:abstractText
Five series of breath-hold (BH) experiments were conducted on eight male subjects with the purpose of partitioning the effects of apnea per se, hypercapnia, and hypoxia on the development and maintenance of BH bradycardia. All BH were 90 s in duration and were achieved by face immersion at room temperature. Of the five series of BH, one was a continuous BH and the remaining included rebreathing at 15-s intervals while the face remained immersed. Comparison of heart rate (HR) responses between the continuous BH with air and that interrupted every 15 s by rebreathing without improving the alveolar gas composition yields the attenuating effect of respiratory activity. The hypercapnic effect was calculated from the difference in HR responses between two series of BH with O2, in which hypoxia was not present and rebreathing was common to both; in one rebreathing was through a CO2 scrubber thus creating different alveolar CO2 levels in the two series. The effect of hypoxia was deduced by finding the difference between the total bradycardial response (continuous BH) and the summed effects of hypercapnia and apnea per se. By this procedure, it was found that apnea and hypoxia reduced the HR by 19 and 18%, respectively, from the pre-BH value, and hypercapnia increased HR by 6% from the pre-BH level, thus accounting for the total 31% reduction in HR in a continuous BH.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0161-7567
pubmed:author
pubmed:issnType
Print
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
166-71
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Effects of hypercapnia, hypoxia, and rebreathing on heart rate response during apnea.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't