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Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry
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Cerebral blood flow autoregulation in early experimental S. pneumoniae meningitis

Michael Pedersen1, Christian T Brandt, Gitte M Knudsen

  • 1Department of Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. m.pedersen@dadlnet.dk

Journal of Applied Physiology (Bethesda, Md. : 1985)
|September 30, 2006
PubMed

Insights

Cerebral blood flow autoregulation is lost in rats with Streptococcus pneumoniae meningitis. This impairment occurs before intracranial pressure rises and may be temporarily restored by hypocapnia.

Area of Science:

  • Neurology
  • Infectious Diseases
  • Physiology

Background:

  • Bacterial meningitis, particularly Streptococcus pneumoniae, can lead to severe neurological complications.
  • Cerebral blood flow (CBF) autoregulation is crucial for maintaining stable brain perfusion.
  • Understanding CBF autoregulation during meningitis is vital for managing intracranial pressure (ICP).

Purpose of the Study:

  • To investigate the impact of Streptococcus pneumoniae meningitis on CBF autoregulation and ICP in a rat model.
  • To assess the effects of normocapnia and hypocapnia on CBF autoregulation and ICP during meningitis.

Main Methods:

  • Induction of meningitis via intracisternal injection of Streptococcus pneumoniae in rats.
  • Measurement of mean arterial blood pressure (MAP), ICP, cerebral perfusion pressure (CPP), and laser-Doppler CBF.
  • Controlled manipulation of CPP and ventilation (normocapnia and hypocapnia).

Main Results:

  • Intracranial pressure (ICP) increased significantly at 24 hours post-inoculation in infected rats.
  • Cerebral blood flow (CBF) autoregulation was lost in infected rats by 12 hours and remained impaired at 24 hours.
  • Acute hypocapnia partially restored CBF autoregulation in infected rats without altering ICP.

Conclusions:

  • Streptococcus pneumoniae meningitis leads to a significant loss of CBF autoregulation.
  • Impairment of CBF autoregulation precedes the rise in ICP during meningitis.
  • Hypocapnia may serve as a potential intervention to temporarily improve CBF autoregulation in meningitis.

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