| Cerebral venous and tissue gases and arteriovenous shunting in the dog. | |
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MedLine Citation:
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PMID: 10475305 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Cerebral venous blood gas values have been used to indicate brain tissue oxygenation. However, it is not clear how cerebral tissue and venous measures may vary under physiologic conditions caused by arteriovenous shunt. The purpose of this study was to measure brain tissue and local cerebral venous oxygen (PO2) and carbon dioxide (P(CO2)) partial pressure during changes in ventilation and to calculate shunt fraction. Eight dogs were anesthetized with isoflurane. After a craniotomy, a Neurotrend probe (Diametrics Inc., St. Paul, MN) that measures P(O2), P(CO2), pH, and temperature was inserted into brain tissue, and a small vein that drained the same tissue was catheterized. Arterial, cerebral venous, and brain tissue P(O2) and Pco2 were measured during random changes in ventilation to produce five different levels of inspired oxygen (room air, 40%, 60%, 80%, 95%) at each of three different end-tidal Pco2 (20 mm Hg, 40 mm Hg, 60 mm Hg). Arteriovenous shunt was calculated from oxygen and C(O2) content in artery, vein, and tissue, representing capillary. Tissue P(CO2) was 8 mm Hg greater than vein Pco2 during hypocapnia and this difference increased to 20 mm Hg during hypercapnia. Vein P(O2) was 8 mm Hg higher than tissue P(O2) during hypocapnia, and this difference increased to 40 mm Hg during hypercapnia. Shunt fraction increased from 10%-20% during hypocapnia to 50%-60% during hypercapnia. These results show that brain vein and tissue P(O2) and P(CO2) differ because of arteriovenous shunting and this difference is increased as end-tidal P(CO2) increases. IMPLICATIONS: We found, in dogs, that the gradient between brain venous and tissue P(O2) and PCO2 is increased with increased arterial P(CO2). The divergence between tissue and venous gases can be described by arterial to venous shunting. |
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Authors:
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G Edelman; W E Hoffman |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Anesthesia and analgesia Volume: 89 ISSN: 0003-2999 ISO Abbreviation: Anesth. Analg. Publication Date: 1999 Sep |
Date Detail:
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Created Date: 1999-09-17 Completed Date: 1999-09-17 Revised Date: 2003-11-14 |
Medline Journal Info:
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Nlm Unique ID: 1310650 Medline TA: Anesth Analg Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 679-83 Citation Subset: AIM; IM |
Affiliation:
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Department of Anesthesiology, University of Illinois at Chicago, 60612, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Arteriovenous Shunt, Surgical* Blood Gas Analysis Body Temperature / physiology Brain Chemistry / physiology* Carbon Dioxide / blood Cerebral Veins Cerebrovascular Circulation / physiology* Dogs Hydrogen-Ion Concentration Oxygen / blood Respiratory Mechanics / physiology |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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