Experimental cerebral hemodynamics

Dewey, Richard C.; Pieper, Heinz P.; Hunt, William E.

doi:10.3171/jns.1974.41.5.0597

Cited by 161 publications

(29 citation statements)

References 12 publications

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“…However, Aaslid and Newell [19]reported the same trends using 8 normal subjects, and Dewey et al [12]found a similar relationship for 25% of monitored anaesthetised monkeys.…”

Section: Discussionmentioning

confidence: 61%

“…The average value for both the baseline phase and the slopes of the transient phases were compared to similar phases from the other groups for the variables MCAV, BP, resistance area product (RAP) and critical closing pressure (CrCP). RAP is defined as RAP = (ABP – CrCP)/CBFV [11]and CrCP is defined as the BP value at which the CBF (or CBFV) becomes zero [12]. Baseline and gradients were compared using the Student t test.…”

Section: Methodsmentioning

confidence: 99%

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Cerebrovascular Response to Dynamic Changes in pCO<sub>2</sub>

et al. 1999

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Fifty-six subjects with carotid artery disease were assessed by measuring the cerebral blood flow velocity (CBFV) change in response to inhalation of 5% CO₂ in air whilst continuously monitoring the blood pressure (BP). Coherent averaging of the data characterised differences in CBFV, BP, resistance area product and critical closing pressure during changes in end-tidal CO₂ (ETCO₂). The results primarily demonstrate that the augmentation of ETCO₂ increases the CBFV and BP, causing a pressure autoregulatory response, and allows the processes of pressure autoregulation and cerebral vascular reserve to be differentiated.

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“…However, Aaslid and Newell [19]reported the same trends using 8 normal subjects, and Dewey et al [12]found a similar relationship for 25% of monitored anaesthetised monkeys.…”

Section: Discussionmentioning

confidence: 61%

Section: Methodsmentioning

confidence: 99%

Cerebrovascular Response to Dynamic Changes in pCO<sub>2</sub>

et al. 1999

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“…We initially hypothesized that Brain Fog is due to orthostatic reductions of cerebral blood flow (CBF) impairing neuronal activation 9 . Although CBF decreases excessively in POTS compared to controls 10 , we later showed mean CBF was abnormally reduced only in some during rapid orthostasis 11 .…”

Section: Introductionmentioning

confidence: 99%

Oscillatory Cerebral Blood Flow Is Associated With Impaired Neurocognition and Functional Hyperemia in Postural Tachycardia Syndrome During Graded Tilt

et al. 2015

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We hypothesize upright cognitive impairment in Postural Tachycardia Syndrome is due to reduced cerebral blood flow. Cerebral blood flow velocity measured by transcranial Doppler ultrasound decreased excessively during 70° tilt in a minority of patients with intermittent hyperpnea/hypocapnia. Incremental tilt showed no difference in mean cerebral blood flow velocity. But, N-Back memory tasking indicated progressive compromised memory, reduced functional hyperemia and reduced neurovascular coupling. Orthostasis caused slow oscillations in cerebral blood flow velocity linked to oscillations in arterial pressure in Postural Tachycardia Syndrome. We also hypothesize that oscillatory cerebral blood flow velocity degrades neurovascular coupling. We performed 2-Back testing supine and during incremental tilts to 15°, 30°, 45° and 60° in 11 Postural Tachycardia Syndrome and 9 controls. Oscillatory arterial pressure, oscillatory cerebral blood flow velocity and neurovascular coupling were similar supine. Oscillatory arterial pressure increased 31, 45, 67, and 93% in Postural Tachycardia Syndrome during tilt, remaining unchanged in control. Oscillatory cerebral blood flow velocity increased by 61, 82, 161, and 264% in Postural Tachycardia Syndrome during tilt remaining unchanged in control. Functional hyperemia decreased from 4.1% to 3.0, 1.1, 0.2, to 0.04% in Postural Tachycardia Syndrome but was unchanged at 4% in control. Percent correct N-Back responses decreased from 78% to 33% in Postural Tachycardia Syndrome while remaining at 89% in controls. In Postural Tachycardia Syndrome, oscillatory cerebral blood flow velocity was linearly correlated with functional hyperemia (r2=0.76). Increased oscillatory cerebral blood flow is associated with reduced neurovascular coupling and diminished cognitive performance in Postural Tachycardia Syndrome.

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“…Critical closing pressure refers to the value of arterial blood pressure below which blood flow in a vessel ceases [8, 9]. There has been debate regarding the existence of, and best method of measuring, critical closing pressure in the cerebral circulation [10, 11, 12].…”

Section: Introductionmentioning

confidence: 99%

A Case of Arrhythmia-Induced Transient Cerebral Hyperaemia

Carey¹,

Eames²,

Panerai

et al. 2000

Cerebrovasc Dis

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Transient cerebral hyperaemia following an arrhythmia has not been previously demonstrated in humans. We report the effects of head-up tilt on a 78-year-old man with neurocardiogenic syncope. During tilt, an asymptomatic arrhythmia caused arterial blood pressure and transcranial Doppler-recorded cerebral blood flow velocity to fall markedly. Upon spontaneous resumption of sinus rhythm, cerebral blood flow velocity increased to values greater than those prior to the arrhythmia. This occurred prior to a full recovery of arterial blood pressure, indicating spontaneous transisent hyperaemia. Pressure-flow velocity graphs support current methods of measuring critical closing pressure and demonstrate a rise in critical closing and a fall in resistance-area product after the arrhythmia.

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Experimental cerebral hemodynamics

Cited by 161 publications

References 12 publications

Cerebrovascular Response to Dynamic Changes in pCO<sub>2</sub>

Cerebrovascular Response to Dynamic Changes in pCO<sub>2</sub>

Oscillatory Cerebral Blood Flow Is Associated With Impaired Neurocognition and Functional Hyperemia in Postural Tachycardia Syndrome During Graded Tilt

A Case of Arrhythmia-Induced Transient Cerebral Hyperaemia

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