Cerebral autoregulation with changes in arterial and cerebral venous pressure
Conference
·
· Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:5506072
The effect of cerebral venous pressure (Pcv) elevation on cerebral autoregulation has been incompletely studied. The authors compared the effect of decreased cerebral perfusion pressure (CPP) by elevated Pcv and decreased arterial pressure (Pa) on cerebral blood flow (CBF) in a canine modified bypass model. CPP of 80, 70, 60, 50, 40 and 30 mmHg were produced by decreasing Pa with intracranial pressure (ICP) and Pcv maintained at 0 mmHg (group 1, n = 5), or by elevating Pcv as Pa was maintained at 80 mmHg (group 2, n = 5. CBF was measured using radiolabeled microspheres, and CMRO/sub 2/ = CBF times arterial-sagittal sinus O/sub 2/ content difference. Cerebrovascular resistance (CVR) = CPP/CBF. In group 1 CBF (ml/100 gm/min) was unchanged from control (36 +/- 4) as CPP was decreased from 80 to 40 mmHg. As CPP was decreased to 30 mmHg, CBF decreased to 28 +/- 1. CVR (mmHg/ml/min/100 gm) was 2.3 +/- 0.3 and progressively decreased to 1.0 +/- 0.1 at CPP of 30 mmHg. In group 2 CBF was 34 +/- 3 and was unchanged as CPP decreased to 50 mmHg. At CPP of 40 and 30 mmHg CBF decreased to 25 +/- 3 and 22 +/- 2 respectively. Control CRV was 2.4 +/- 0.2 and progressively decreased to 1.4 +/- 0.1 as CPP decreased to 30 mmHg. CMRO/sub 2/ was unchanged from control in both groups. Thus, CBF is maintained to low CPP regardless of whether vascular transmural pressure was decreased (decrease Pa) or increased (increased Pcv) demonstrating that the myogenic mechanism of autoregulation may be unimportant in normoxic dogs.
- Research Organization:
- Johns Hopkins Medical Institution, Baltimore, MD
- OSTI ID:
- 5506072
- Report Number(s):
- CONF-8604222-
- Conference Information:
- Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MODELS
BLOOD FLOW
BLOOD PRESSURE
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DOGS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MICROSPHERES
NERVOUS SYSTEM
ORGANS
RADIOISOTOPES
TRACER TECHNIQUES
VERTEBRATES
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MODELS
BLOOD FLOW
BLOOD PRESSURE
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DOGS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MICROSPHERES
NERVOUS SYSTEM
ORGANS
RADIOISOTOPES
TRACER TECHNIQUES
VERTEBRATES