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At least 19 recordsLinked to original sources
PubMed1978

[General and cerebral hemodynamics in atherosclerosis of the cerebral vessels with transient disorders of cerebral circulation].

The authors studied general and cerebral hemodynamics in 51 patients with cerebral atherosclerosis transient disorders of cerebral circulation. The studies demonstrated correlation between the indices of general peripheral resistance of the blood flow, cardiac and pulse indices. The rate of the blood flow in the segment hand-ear was slower. REG studies detected deficit of blood repletion, intrahemispheric asymmetry, a drop in the elasticity of the vascular wall. These data may be used in prescribing pathogenetical treatment to patients with transient disorders of cerebral circulation.

Aged↗
PubMed1979

[State of systemic and cerebral hemodynamics in patients with transient cerebral circulatory disorders].

In 50 patients with transient disorders of cerebral circulation due to hypertensive disease (27 cases), and combinations of hypertensive disease with atherosclerosis (23 cases) the authors by means of diluting Ewans blue stain (T-1824) studied the indices of general hemodynamics compared to that of REG data . For control purposes 10 patients with hypertensive disease in concomitance with atherosclerosis without transient disorders of cerebral circulation and 20 normals were studied. The study permitted to detect signs of disturbed general and cerebral hemodynamics which were most expressed in patients with severe cerebro-vascular crises, accompanied by a drop in the cardiac and pulse index, an increase of the general and specific peripheral resistance, a slowing of the blood flow rate on the segment hand-ear, an increase of the tone and drop of elasticity in the cerebral vessels, a decrease of cerebral blood repletion. Insufficiency of general hemodynamics leads to disorders of cerebral hemodynamics and unfavourably influences the development of the disease and the outcome of cerebrovascular crises.

Adult↗
PubMed1978

Alterations in regional cerebral hemodynamics and metabolism produced by focal cerebral ischemia.

Since diffuse changes in blood flow and metabolism occur in the brain following a focal ischemic insult, changes of cerebral blood flow on the side opposite a cerebral infarction were observed. We have examined the course of the cerebral hemodynamic changes occurring in 15 patients with unilateral acute strokes. In 12 of these patients, significant blood flow changes (over 15%) occurred in the nonischemic hemisphere during the period of observation. A similar time course of change was found in the ischemic hemisphere and the flow changes in the two hemispheres appeared parallel to one another (diaschisis). Thus we have demonstrated a significant reduction in flow in the contralateral cortex following a unilateral ischemic insult. This reduction in flow was of the order of 38% from the control value which agrees quite well with the reduction in cortical glucose consumption of the order of 31%. We postulate that these changes are the hemodynamic and metabolic concomitants of diaschisis and may in part be due to a transneuronal depression of function.

Animals↗
PubMed1978

[Cerebral hemodynamics in the vegetative state patients--relationship between patterns of dysautoregulation and prognosis (author's transl)].

The pathophysiological analysis of cerebral hemodynamic mechanisms and its metabolism in the vegetative patients was not enough until now. It was reported in this paper that the correlation between cerebral hemodynamics, metabolism and neurological function was analysed in 14 patients with vegetative state caused by cerebrovascular disorders. The materials consist of 14 vegetative patients due to 7 hypertensive intracerebral hemorrhage, 6 subarachnoid hemorrhage and one cerebral infarction. In all of them, the cerebral hemodynamics such as cerebral blood flow (CBF), CO2 reactivity and autoregulation, and cerebral metabolism were measured sequencially by 133Xe clearance methods. In the majority of cases, both values of mean hemispheric CBF and cerebral oxygen consumption (CMRO2) were markedly decreased with severe impairments of autoregulation and CO2 reactivity on the bilateral hemispheres but much more significatly on the affected hemispheres. Futhermore, from view points of the pressureflow relationship in the CBF studies, the patterns of dysautoregulation could be classified into 2 types as follows; Type 1 is the complete loss type, which has no plateau formation in all ranging of systemic arterial blood pressure (SABP). Type 2 is the incomplete loss type with 2 subdivisions, in which the abnormal narrowing plateaus are recognized in relatively higher or lower range of SABP (called as the upper or the lower type of incomplete loss type respectively). And then, the phenomen, which we gave a term as "shift-off phenomenon", was recognized in 8 cases that the proper values of resting SABP was seated outside the plateau level of the auto-regulatory capacity. The correlation between CBF dynamics and the grade of vegetative state was analysed. In 2 cases with slight communications (vegetative grade1), mean hemispheric CBF value was 32.5 (ml/100 g/min.) and CMRO2 was 2.01 (ml/100 g/min.) with the normal or the upper type in incomplete loss of dysautoregulation. In 3 cases of vegetative grade 2, who could slightly response to vocal order, mean CBF and CMRO2 showed 27.0 +/- 2.0 and 1.7 +/- 0.08 respectively. In these cases, dysautoregulations with the upper type incomplete loss were recognized. In 3 cases of vegetative grade 3, who had only spontaneous movement of body and slight emotional expression but no response to vocal order, mean CBF was in 22.4 +/- 1.9 and CMRO2 in 1.28 +/- 0.21. The patterns of dysautoregulation showed the lower type of incomplete loss. We had experienced the shift-off phenomenon in all of 5 cases with the upper type of incomplete loss and in 3 of 7 cases with the lower type of incomplete loss dysautoregulation. As conclusion, in cases of vegetative grade 2 or 3 whose patterns of dysautoregulation are the upper or lower type of incomplete loss with the shift-off pnenomenon, it would be a useful therapeutic method to get away from vegetative state that SABP could be corrected and controlled within the proper plateau level of autoregulation by the suitable administration of some vasoactive agents.

Adult↗
PubMed1978

Cerebral hemodynamics and metabolism in pseudotumor cerebri.

A comprehensive analysis of cerebral hemodynamics and metabolism was carried out in 14 patients with pseudotumor cerebri. Tracer techniques were employed to measure cerebral blood flow (CBF) and vascular reactivity to acute changes in arterial carbon dioxide tension and blood pressure, cerebral blood volume (CBV), and the cerebral metabolic rate for oxygen and glucose. There was a small reduction (p less than 0.01) in CBF (44 +/- 7 ml/100 gm/min; normal, 54 +/- 9) with normal vascular reactivity; an increase (p less than 0.005) in CBV (4.8 +/- 0.8 ml/100 gm; normal, 3.6 +/- 0.5), and normal cerebral metabolism. We conclude that an abnormality of the cerebral microvasculature is responsible for an elevation in CBV, but the intracranial hypertension can be explained only by tissue swelling due to an increase in water content. The relationship between the vascular abnormality and the tissue swelling remains to be defined.

Adolescent↗
PubMed1977

Cerebral hemodynamics in migraine.

Clinical and angiographic findings in migraine are briefly reviewed in relation to cerebral hemodynamic changes shown by regional cerebral blood flow (rCBF) studies. Three cases of migraine studied by the intracarotid xenon 133 method during attacks are reported. In classic migraine, with typical prodromal symptoms, a decrease in cerebral blood flow has been demonstrated during the aura. Occasionally, this flow decrease persists during the headache phase. In common migraine, where such prodromata are not seen, a flow decrease has not been demonstrated. During the headache phase of both types of migraine, rCBF has usually been found to be normal or in the high range of normal values. The high values may represent postischemic hyperemia, but are probably more frequently secondary to arousal caused by pain. Thus, during the headache phase rCBF may be subnormal, normal or high. These findings do not exclude the possibility of distension of the larger intracranial arteries during migraine headache, but the angiographic evidence, however limited, does not support this speculation.

Adult↗
PubMedDate not supplied

[Deep hypotension induced by sodium nitroprusside in neurosurgery. II.--Cerebral hemodynamic effects and metabolic rate of oxygen (author's transl)].

The cerebral hemodynamic effects of sodium nitroprusside (S. N.) have been the object of animal studies mainly. During the only human study performed, the drop in mean arterial pressure (MAP) is limited to 67 mm Hg. The study of the evolution of cerebral blood flow (CBF) in cases of more severe hypotension (MAP less than 45 mm Hg) seems of some interest. The study was composed of the measurement of the CBF using Xenon 133 and the calculation of cerebral vascular resistances (CVR) as well as cerebral metabolic rate of oxygen (CMRO2). Eleven patients with an average age of 37 years underwent surgery for cerebral aneurism 10 to 15 days after the inaugural hemorrhagic accident, under narconeuroleptanalgesia and stable ventilatory conditions. They are divided into 2 groups: Group I, 9 patients with normal levels of consciousness; Group II, 2 patients either agitated or obnubilated. The study is composed of 3 successive measures: (1) (T0) during stable anesthesia just prior to hypotension; (2) (T1) after 5 minutes of hypotension (MAP = 40 +/- 7 MM Hg); (3) (T2) 20 minutes after having stopped S. N. infusion. For the 9 patients in Group I, CBF remains unchanged at T1, the CVR decreases (p less than 0.001) and CMRO2 decreases (p less than 0.05). At T2 all of these parameters return to T0 values. The postoperative clinical evolution is favorable and uncomplicated. For the 2 patients in Group II the CBF, initially higher, falls from 20 to 30 p. cent at T1 with a drastic reduction in CMRO2. Despite the improvement of these parameters at T2, a prolonged postoperative coma is observed. This study suggests that CBF and CMRO2 are important parameters to monitor during controlled severe hypotension. Decrease in MAP must be less than 50 p. cent of control value and time-limited.

Acid-Base Equilibrium↗
PubMed2025

Impact of Chewing Behavior Change on Cognition and Cerebral Hemodynamics.

BACKGROUND: Impaired chewing ability is a recognized risk factor for cognitive decline in older adults, potentially due to reduced neural stimulation in cognition-related brain regions. While short-term studies have demonstrated transient increases in neural activity from chewing, the sustained cognitive and neurophysiological effects of encouraging thorough chewing habits in daily life remain unclear. OBJECTIVE: This randomized controlled trial investigated whether promoting thorough chewing during meals could improve cognitive function and cerebral hemodynamics in older adults. METHODS: Fifty participants aged 65 y or older were randomly assigned to either a 1-mo intervention group, which used a wearable device to monitor and increase chewing strokes during meals, or a control group that maintained usual chewing habits. Chewing behavior, cognitive performance (including memory and executive function via the color Stroop test), and cerebral hemodynamics in the dorsolateral prefrontal cortex (DLPFC) were measured at baseline and after 1 mo. Statistical analyses included t tests, chi-square tests, 2-way analysis of variance with post hoc tests, Pearson correlations, and generalized linear models to evaluate group differences and associations between chewing and cognitive outcomes. RESULTS: Significant time-by-group interactions were observed for memory, F(1, 48) = 6.24, P = 0.043, and hemodynamic responses in the left DLPFC, F(1, 48) = 6.19, P = 0.013. The intervention group showed increased chewing frequency (P = 0.017), improved memory performance, and reduced left DLPFC responses compared with controls. Chewing frequency was positively correlated with Stroop test scores (r = 0.53, P = 0.010) and negatively with hemodynamic changes in the left DLPFC (r = -0.30, P = 0.040). Although improvements in other cognitive outcomes and hemodynamic measures favored the intervention group, these differences did not reach statistical significance. CONCLUSIONS: Promoting intentional chewing habits for 1 mo may enhance memory-related cognitive performance and neural efficiency in the DLPFC during working memory tasks in older adults. This nonpharmacologic, low-burden strategy warrants further research with longer interventions to support cognitive health and dementia prevention. TRIAL REGISTRATION ID: UMIN000044280Knowledge Transfer Statement:This study demonstrates that promoting thorough chewing habits in older adults can improve memory and enhance neural efficiency in the brain. Encouraging intentional mastication is a simple, nonpharmacologic approach that may help maintain cognitive health and prevent dementia, providing a practical strategy for clinicians and policymakers to support healthy aging.

Humans↗
PubMed1976

Cerebral hemodynamic crisis. Physiology, pathophysiology, and approach to therapy.

The physiology and pathophysiology of the cerebral circulation have been discussed in relation to treatment of the cerebral hemodynamic crisis. Data are presented to show how cerebral vascular resistance, the intracranial compartments, and brain metabolic demand may be manipulated to effect internal decompression and raise local perfusion pressures. It is quite apparent that irreversibility occurs rapidly in cases of complete ischemia and therapeutic success is often limited by this fact. Application of sound therapeutic principles will limit the extent of cellular destruction. Of particular importance to the general surgeon treating the multiply injured patient, is the effect of anesthesia on intracranial pressure in patients with compromised intracranial volume reserve.

Adrenal Cortex Hormones↗
PubMed1977

The effect of intraarterial administered aminophylline on cerebral hemodynamics in man.

The dose-effect relationship of intracarotid administered aminophylline on cerebral hemodynamics in man was investigated by means of an intraarterial 133Xenon injection method. A dose dependent vasoconstriction was clearly demonstrated. The maximum efficacy expressed as measured decreased in global cerebral blood flow was 21.9 per cent +/- 6.2 SD. Administration of as little as 1 mg aminophylline produced a measureable vasoconstriction.

Aged↗
PubMed1979

Methylprednisolone in the prevention of cerebral hemodynamic and metabolic disorders during endotoxin shock in the dog.

These results provide evidence that steroid pretreatment and subsequent post-treatment prevent cerebral hemodynamic and metabolic alterations during four hours of Escherichia coli endotoxin shock in the dog. However, in this study, no data are provided on how the steroid prevents an increase in cerebral vascular resistance, and no clear answer is available in the literature. While active vasodilation or alpha-adrenergic blocking properties, or both, have been attributed to glucocorticoids, recent evidence does not support these findings during normal conditions or circulatory shock. If the increase in cerebral vascular resistance is passive, steroids may help by preventing platelet aggregation, cell disruption and subsequent microvascular plugging. Intravenously administered fluids, dextran-saline solution, while in themselves are probably not important to survival, may augment cerebral blood flow during shock through a blood dilutional effect. Finally, it is possible that steroids act to permit normal, long term cerebral auto-regulation, which is apparently impaired during endotoxin shock in the dog.

Animals↗
PubMedDate not supplied

Cerebral hemodynamics in Shy-Drager syndrome: variability of cerebral blood flow dysautoregulation and the compensatory role of chemical control in dysautoregulation.

Cerebrovascular autoregulation and CO2 reactivity were measured repeatedly in 3 patients with the multiple system atrophy type of autonomic insufficiency (Shy-Drager syndrome) by means of the 133Xe injection method. The degree of cerebral blood flow (CBF) dysautoregulation showed day-to-day variations in 2 of the 3 patients. The CO2 reactivity was normal or supernormal in the supine position in patients with impaired autoregulation. In the head-up position the response to CO2 was slightly suppressed in 2 of the patients, suggesting that chemical control may have tended to compensate for CBF dysautoregulation. It is concluded that the mechanism of chemical control of the cerebrovasculature is different from that which controls autoregulation and may have partially compensated for CBF dysautoregulation.

Carbon Dioxide↗
PubMed1979

Cerebral hemodynamic changes during plateau waves in brain-tumor patients.

The plateau wave, one of the wave forms observed in patients with increased intracranial pressure, has previously been extensively investigated, but its pathophysiological aspect is as yet unclear. The authors undertook a study of cerebral hemodynamic changes while the plateau waves were observed in five brain-tumor patients. Although the number of cases studied was small, a remarkable decrease in cerebrovascular resistance was seen in all patients during the plateau waves. It is suggested that the plateau waves are caused by a marked cerebral vasodilatation. The present results support the thesis that cerebral blood volume is increased during the plateau waves. The plateau waves are closely related to the intrinsic vasomotor control of cerebral circulation, and can occur as long as cerebral vasodilating ability is maintained, irrespective of the existence of cerebral autoregulation.

Adult↗
PubMed1979

Central and cerebral hemodynamics and metabolism of the healthy man during head-down tilting.

Experiments on six healthy test volunteers, who underwent simultaneous catheterization of different cardiovascular compartments, were carried out to study the effect of head-down tilting at an angle of -20 degrees on the central and cerebral hemodynamics and metabolism. By the third hour of exposure, the test subjects showed a decrease in the systolic arterial pressure and increases in the systolic pressure of the right ventricle, heart rate, cardiac output, and oxygen intake. They also displayed a trend for an increase in the content of adenosine triphosphate, a decrease in the content of pyruvic acid, and essentially no changes in the concentration of lactic acid and activity of lactate dehydrogenase in the arterial blood and in the blood flowing out from the brain. The oxygen arteriovenous difference for the systemic and cerebral circulation decreased by 24% and 13%, respectively. The above circulatory and metabolic changes seem to reflect processes of adaptation of the human body to functioning under conditions of cephalad fluid shifts.

Acid-Base Equilibrium↗
PubMed1979

[State of general and cerebral hemodynamics in patients with ischemic strokes].

In 64 patients with ischemic strokes that occurred on the background of atherosclerosis (33) and a combination of atherosclerosis with arterial hypertension (31) using the dilution method of Evans's blue the authors studied indices of general hemodynamics compared to rheoencephalographic data. Twenty similar patients without signs of brain circulation disturbances and 20 healthy persons were taken as control groups. In 69% of the patients with ischemic strokes deep disturbances of general hemodynamics were observed. An increase of tonus, a decrease of elasticity of cerebral vessels and deficit of pulse blood repletion were determined rheoencephalographically. Insufficiency of general hemodynamics in conditions of changed autoregulation of brain circulation promotes development of ischemic disorders of brain circulation and unfavourably influences the course and outcome of the stroke.

Adult↗
PubMed1978

Althesin in neurosurgical patients: effects on cerebral hemodynamics and metabolism.

The effect of althesin 0.5 ml/10 kg on arterial blood pressure, intracranial pressure, cerebral blood flow and oxygen uptake was studied on 19 occasions in 16 patients with varied cerebral pathology. Cerebral blood flow (CBF) was measured using the intracarotid 133xenon method and a 35-channel scintillation detector after cannulation of the internal carotid artery, the internal jugular bulb and the lateral cerebral ventricle. Arterial and intracranial pressures were recorded continuously. Blood gas tensions were measured in simultaneously drawn samples from the internal carotid artery and the jugular bulb. Cerebral oxygen uptake was calculated from the product of CBF and arteriovenous oxygen content difference. Control values were obtained with the patients under a basic general anesthesia, consisting of N2O/O2 pancuronium. The effect of a bolus injection of althesin was then studied 1 and 20 min after the injection. A significant reduction in intracranial pressure, cerebral blood flow and metabolism at 1 min was found to have essentially subsided 20 min after the injection. In patients with focal brain damage, regional flow analysis revealed a paradoxical increase in flow after althesin in the areas corresponding to the focus.

Adolescent↗
PubMed1979

Intraoperative evaluation of cerebral hemodynamics using directional Doppler technique. Part 1: Arteriovenous malformations.

The use of a pulsed echo Doppler technique during surgery for cerebral arteriovenous malformation is described. The equipment and the methods employed are presented. The main advantages are easy determination of flow direction and pattern of the vasculature involved, allowing a precise discrimination between inflow and outflow channels. Deep-seated malformations, not visible at the brain surface, can be located with the Doppler technique. The ultrasound probe was placed on the brain surface with a slight pressure on the intact pia mater. The precise direction and depth of the malformation could be determined in relation to the recording site. This facilitated the planning of cortical incisions, identification of vessels involved, and the vascular procedure to be employed.

Adolescent↗