Linked Life Data

17932301

Source:http://linkedlifedata.com/resource/pubmed/id/17932301

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2007-12-6
pubmed:abstractText
We hypothesized that chronic intermittent hypoxia (CIH) would induce a predisposition to apnea in response to induced hypocapnia. To test this, we used pressure support ventilation to quantify the difference in end-tidal partial pressure of CO(2) (Pet(CO(2))) between eupnea and the apneic threshold ("CO(2) reserve") as an index of the propensity for apnea and unstable breathing during sleep, both before and following up to 3-wk exposure to chronic intermittent hypoxia in dogs. CIH consisted of 25 s of Pet(O(2)) = 35-40 Torr followed by 35 s of normoxia, and this pattern was repeated 60 times/h, 7-8 h/day for 3 wk. The CO(2) reserve was determined during non-rapid eye movement sleep in normoxia 14-16 h after the most recent hypoxic exposure. Contrary to our hypothesis, the slope of the ventilatory response to CO(2) below eupnea progressively decreased during CIH (control, 1.36 +/- 0.18; week 2, 0.94 +/- 0.12; week 3, 0.73 +/- 0.05 l.min(-1).Torr(-1), P < 0.05). This resulted in a significant increase in the CO(2) reserve relative to control (P < 0.05) following both 2 and 3 wk of CIH (control, 2.6 +/- 0.6; week 2, 3.7 +/- 0.8; week 3, 4.5 +/- 0.9 Torr). CIH also 1) caused no change in eupneic, air breathing Pa(CO(2)); 2) increased the slope of the ventilatory response to hypercapnia after 2 wk but not after 3 wk compared with control; and 3) had no effect on the ventilatory response to hypoxia. We conclude that 3-wk CIH reduced the sensitivity of the ventilatory response to transient hypocapnia and thereby increased the CO(2) reserve, i.e., the propensity for apnea was reduced.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
8750-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
103
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1942-9
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Chronic intermittent hypoxia increases the CO2 reserve in sleeping dogs.
pubmed:affiliation
The John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural