| Autor: |
Herbert A. Saltzman, Herbert O. Sieker, Albert Heyman, L. J. Klein |
| Rok vydání: |
1964 |
| Předmět: |
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| Zdroj: |
The American Journal of Medicine. 37:263-268 |
| ISSN: |
0002-9343 |
| DOI: |
10.1016/0002-9343(64)90010-5 |
| Popis: |
Various physiologic factors influencing syncope induced by combined Valsalva maneuver and hyperventilation were studied in volunteer subjects. Syncope almost always occurred at a critical level of mean arterial pressure of 51 mm. Hg and arterial blood carbon dioxide tension of 26 mm. Hg. Although a marked reduction in blood pressure alone occasionally resulted in loss of consciousness, a combination of hypotension and hypocapnia was usually necessary for syncope to occur. The inhalation of 100 per cent oxygen or the intravenous administration of 50 per cent glucose failed to prevent or delay the onset of syncope, but occasionally the concomitant electroencephalographic abnormalities were diminished by hyperglycemia. These studies indicate that the reduction in cerebral blood flow associated with hyperventilation is an important predisposing factor in syncope, particularly when associated with a transient decrease in effective blood pressure. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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