Regional cerebrovascular responses to progressive hypotension after traumatic brain injury in cats

D. S. DeWitt, D. S. Prough, C. L. Taylor, J. M. Whitley, D. D. Deal, S. M. Vines

Research output: Contribution to journalArticle

75 Scopus citations

Abstract

We investigated the effects of hypotension on cerebral blood flow (CBF) after traumatic brain injury (TBI) in cats. Isoflurane-anesthetized cats were prepared for TBI and for microsphere measurements of total (T) and regional (r) CBF. Four groups were studied: sham injury (group I, n = 6); TBI (group II, n = 6); isoflurane anesthesia, no TBI or hypotension (group III, n = 4); and isoflurane and TBI, no hypotension (group IV, n = 8). After TBI or sham trauma, mean arterial pressure (MAP) was reduced to 80, 60, and 40 mmHg by hemorrhage. Group I TCBF did not change significantly from baseline until MAP reached 40 mmHg, but rCBF was more dependent on MAP in anterior hemispheric than in brain stem regions. Group II TCBF was significantly lower than baseline, and group I TCBF at all levels of hypotension and autoregulation was impaired at higher MAP levels in anterior than in posterior brain regions. Groups III and IV indicated that decreases in TCBF were not due to duration of the preparation or to TBI in the absence of hemorrhagic hypotension. We conclude that global and regional autoregulation are absent in response to hemorrhagic hypotension after TBI.

Original languageEnglish (US)
Pages (from-to)H1276-H1284
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume263
Issue number4 32-4
DOIs
StatePublished - 1992

Keywords

  • central nervous system
  • cerebral blood flow
  • hemorrhagic shock
  • hemorrhagic trauma
  • radioactive microspheres

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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