Discussion of presentation by A.G.B. Kovach

  • James A. SpathJr.
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 78)


Autoregulatory mechanisms tend to maintain cerebral blood flow during hemorrhagic shock. Cerebral blood flow is not significantly altered until the perfusion pressure falls below 70 mm Hg during hemorrhage. The mechanism of cerebral autoregulation during hemorrhagic hypotension is unclear, although both metabolic and myogenic components appear to mediate cerebral autoregulation.1 Investigations by Dr. Kovach and others have observed that although total cerebral blood flow may only be moderately decreased in hemorrhage, areas of severe ischemia may be adjacent to more normally perfused tissue.2 Such studies define the need for measuring regional cerebral blood flows as well as total cerebral blood flow in hemorrhagic shock. Using hydrogen washout and thermodilution techniques, Kovach et al. 2,3 demonstrated a 60% reduction in hypothalamic flow after hemorrhage to 35 mm Hg. The authors concluded that autoregulation in the hypothalamus during hemorrhage differed from other regions of the brain. In contrast, Slater et al. 4 using radioactive microspheres reported similar patterns of blood flow alterations in cerebellum, gray matter, white matter, and the hypothalamus of conscious dogs subjected to hemorrhage.


Cerebral Blood Flow Hemorrhagic Shock Regional Cerebral Blood Flow Cerebral Autoregulation Cerebral Vasculature 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Betz E: Cerebral blood flow: Its measurement and regulation. Physiol. Rev. 52:595–630, 1972.PubMedGoogle Scholar
  2. 2.
    Kovach AGB, Sandor P: Cerebral blood flow and brain function during hypotension and shock. In Knovil E, Sonnerschein RR, Edelman IS (Editors): Annual Review of Physiology. Palo Alto, Annual Reviews Inc, 1976, pp 571–796.Google Scholar
  3. 3.
    Kovach AGB: The function of the central nervous system during hemorrhage. J. Clin. Pathol. 23 Suppl. 4:202–212, 1970.CrossRefGoogle Scholar
  4. 4.
    Slater G, Viadeck BC, Bassin R, Brown RS, Shoemaker WC: Sequential changes in cerebral blood flow and distribution of flow within the brain during hemorrhagic shock. Ann. Surg. 181: 1–4, 1975.PubMedCrossRefGoogle Scholar
  5. 5.
    Marcus ML, Heistad DD, Erhardt JC, Abboud FM: Total and regional cerebral blood flow measurement with 7–10-, 15-, 25-, and 50-µm microspheres. J. Appl. Physiol. 40:501–507, 1976.PubMedGoogle Scholar
  6. 6.
    Fitch W, MacKenzie ET, Harper AM: Effects of decreasing arterial pressure on cerebral blood flow in the baboon. Circ. Res. 37:550–557, 1975.PubMedCrossRefGoogle Scholar
  7. 7.
    Reivich M: Arterial PCO2 and cerebral hemodynamics. Am. J. Physiol. 206:25–35, 1964.PubMedGoogle Scholar
  8. 8.
    Emerson TE Jr, Parker JL: Cerebral hemodynamics during endotoxin shock in the dog. Circ. Shock 3:21–29, 1976.Google Scholar
  9. 9.
    Reivich M, Kovach AGB, Spitzer JJ, Sandor P: Cerebral blood flow and metabolism in hemorrhagic shock in baboons. In Kovach AGB, Stoner HB, Spitzer JJ (Editors): Neurohumeral and Metabolic Aspects of Injury. New York, Plenum Press, 1973, pp 19–26.Google Scholar

Copyright information

© Plenum Press, New York 1977

Authors and Affiliations

  • James A. SpathJr.
    • 1
  1. 1.Jefferson Medical CollegePhiladelphiaUSA

Personalised recommendations