Role of Microvascular Shunts in the Loss of Cerebral Blood Flow Autoregulation

  • Edwin M. Nemoto
  • Denis E. Bragin
  • Gloria Statom
  • Mark Krasberg
  • Suguna Pappu
  • Bobby Sena
  • Tracey Berlin
  • Kim Olin
  • Howard Yonas
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 812)

Abstract

Historically, determination of the critical cerebral perfusion pressure (CPP) was done in animals by a progressive lowering of arterial pressure yielding a nominal critical CPP of 60 mmHg. Subsequently, it was shown that if the CPP was decreased by increasing intracranial pressure (ICP), critical CPP fell to 30 mmHg. This discrepancy was unexplained. We recently provided evidence that the decrease in critical CPP was due to microvascular shunting resulting in maintained cerebral blood flow (CBF) at a lower CPP. We demonstrated by a progressive increase in ICP in rats using two-photon laser scanning microscopy (2PLSM) that the transition from capillary to microvascular shunt flow is a pathological process. We surmise that the loss of CBF autoregulation revealed by decreasing arterial pressure occurs by dilation of normal cerebral blood vessels whereas that which occurs by increasing ICP is due to microvascular shunting. Our observations indicate that the loss of CBF autoregulation we observed in brain injured patients that changes on an hourly or daily basis reflects an important pathophysiological process impacting on outcome that remains to be determined.

Keywords

Brain Cerebral blood flow Edema Intracranial pressure Microvascular shunts Thoroughfare channels 

Notes

Acknowledgments

Supported in part by: NIH Grants NS061216, NS051639 and UNM HSC COBRE program (P20 RR15636).

References

  1. 1.
    Guillaume J, Janny P (1951) Continuous intracranial manometry; physiopathologic and clinical significance of the method. Presse Med 59(45):953–955PubMedGoogle Scholar
  2. 2.
    Ingvar DH (1964) The regulation of cerebral circulation. Acta Anaesthesiol Scand Suppl 15(15):43–46CrossRefGoogle Scholar
  3. 3.
    Jennett WB, Harper AM, Miller JD et al (1970) Relation between cerebral blood-flow and cerebral perfusion pressure. Br J Surg 57(5):390PubMedGoogle Scholar
  4. 4.
    Waltz AG, Yamaguchi T (1970) Pressure-flow relationships of the cerebral vasculature: autoregulatory responses to changes of perfusion pressure produced without drugs or hemorrhage. Trans Am Neurol Assoc 95:326–327PubMedGoogle Scholar
  5. 5.
    Brain Trauma Foundation, American Association of Neurological Surgeons, Congress of Neurological Surgeons, Joint Section on Neurotrauma and Critical Care, AANS/CNS, Bratton SL, Chestnut RM, Ghajar J et al (2007) Guidelines for the management of severe traumatic brain injury. IX. Cerebral perfusion thresholds. J Neurotrauma 24(1):S1–S116CrossRefGoogle Scholar
  6. 6.
    Miller JD, Stanek A, Langfitt TW (1972) Concepts of cerebral perfusion pressure and vascular compression during intracranial hypertension. Prog Brain Res 35:411–432CrossRefPubMedGoogle Scholar
  7. 7.
    Grubb RL Jr, Raichle ME, Phelps ME et al (1975) Effects of increased intracranial pressure on cerebral blood volume, blood flow, and oxygen utilization in monkeys. J Neurosurg 43(4):385–398CrossRefPubMedGoogle Scholar
  8. 8.
    Johnston IH, Rowan JO, Harper AM, Jennett WB (1972) Raised intracranial pressure and cerebral blood flow: I. Cisterna magna infusion in primates. J Neurol Neurosurg Psychiat 35:285–296CrossRefPubMedPubMedCentralGoogle Scholar
  9. 9.
    Hauerberg J, Juhler M (1994) Cerebral blood flow autoregulation in acute intracranial hypertension. J Cereb Blood Flow Metab 14:519–525CrossRefPubMedGoogle Scholar
  10. 10.
    Bragin DE, Bush RC, Müller WS et al (2011) High intracranial pressure effects on cerebral cortical microvascular flow in rats. J Neurotrauma 28(5):775–785CrossRefPubMedPubMedCentralGoogle Scholar
  11. 11.
    Bragin DE, Bush RC, Nemoto EM (2013) Effect of cerebral perfusion pressure on cerebral cortical microvascular shunting at high intracranial pressure in rats. Stroke 44(1):177–181CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2014

Authors and Affiliations

  • Edwin M. Nemoto
    • 1
  • Denis E. Bragin
    • 1
    • 2
  • Gloria Statom
    • 1
  • Mark Krasberg
    • 1
  • Suguna Pappu
    • 1
  • Bobby Sena
    • 1
  • Tracey Berlin
    • 1
  • Kim Olin
    • 1
  • Howard Yonas
    • 1
  1. 1.Department of NeurosurgeryUniversity of New MexicoAlbuquerqueUSA
  2. 2.BRaIN Imaging CenterUniversity of New MexicoAlbuquerqueUSA

Personalised recommendations