View clinical trials related to Cerebral Blood Flow.
Filter by:Oral supplements containing exogenous ketones have recently become available and represent a novel tool for increasing plasma ketone bodies without the need for dietary restriction. Early evidence suggests that oral ketone supplements may enhance cerebral blood flow (CBF). However, a higher dose of a ketone monoester has been shown to slightly lower blood pH and reduce end-tidal CO2 (PetCO2) due to compensatory hyperventilation, which is accompanied by parallel reductions in CBF. Whether reductions in PetCO2 causes reductions in CBF is currently unknown. The purpose of this study is to investigate the effect of manipulating PetCO2 at normocapnia (PetCO2 maintained at baseline) or poikilocapnia (no PetCO2 targeting; breathing room air), following the ingestion of a dose of a ketone monoester on CBF and cerebrovascular reactivity to CO2 in young adults.
The cognitive trajectory varies among non-demented older adults. In a 12-year follow-up study, we found approximately 5% participants presented rapid cognitive decline. Cardiovascular diseases increased the risk of cognitive decline. However, the influence of cardiovascular risk factors on cognitive decline remained inconsistent. Besides, the potential mechanism of the cardiovascular risk factors and cognitive function has not been fully investigated. Therefore, the proposed program will include two sub-studies. The first sub-study will use the longitudinal data from the Chinese Longitudinal Healthy Longevity Survey to evaluate the influence of cardiovascular risk factors on the trajectories of cognitive function. The second sub-study will recruit cognitive intact older adults with different levels of cardiovascular risk factors. The association among cardiovascular risk factors, cerebral blood flow, brain functional connectivity and cognitive function will be investigated with structural equation modeling. The findings of the proposed program will provide novel insight on preventing cognitive decline from the angle of maintaining healthy vascular function, and will provide evidence in elucidating the potential neurovascular mechanism between cardiovascular risk factors and cognitive function.
A randomized controlled trial will be conducted. Patients with asymptomatic intracranial / carotid stenosis will be randomized into two arms (1:1): an intervention arm and a control arm. Patients in the intervention arm will be treated with standard medical treatment combined with Natto Products V, whereas Patient in the control arm will be treated with only standard medical treatment . And the impact of Natto Products V on improving cerebral blood flow and cognitive function in patients with asymptomatic intracranial / carotid stenosis will be assessed by neuropsychological scale and multimode magnetic resonance imaging.
Although spontaneous hyperventilation patients with aneurysmal subarachnoid hemorrhage closely associated with poor outcomes, the standard therapy remains unavailable. Remifentanil has the pharmacological characterization of respiratory inhibition, mainly prolonging the expiratory time and decreasing the respiratory rate while preserving the respiratory drive. The investigators hypothesis that spontaneous hyperventilation could be corrected by titrating the dose of remifentanil and cerebral blood flow will augment during this process.
Cerebral blood flow measurement, which is applied to patients with cerebrovascular-related diseases, provides useful information about hemodynamic status. There was a method using Doppler ultrasound and phase contrast (PC) MRI, but it was not widely used in clinical practice due to limitations in reproducibility between examiners, complexity of procedure, and time-intensive protocol. We intend to measure cerebral blood flow through the signal-intensity gradient (SIG) technique using Time-of-Flight (TOF) of brain magnetic resonance imaging, which can compensate for the shortcomings of the existing research methods. In addition, by analyzing the correlation with the previous methods, Doppler ultrasound and PC MRI, we will evaluate the effectiveness of our new method.
Little is known about how implementation of pneumoperitoneum contributes to cerebral blood flow in pediatrics. We investigated this question in patients undergoing laparoscopic surgery, hypothesizing that cardiorespiratory changes during this procedure would reduce cerebral perfusion.
We planned to evaluate cerebral blood flow and its association with age, blood pressure, and end tidal carbon dioxide in small pediatric using transfontanelle ultrasound during general anesthesia.
To investigate the effect of levcromakalim/placebo infusion on cranial arteries after glibenclamide administration.
Preterm infants often need peripheral artery catheters for invasive blood pressure recording and to facilitate blood sampling. Near infrared spectroscopy is a method to evaluate cerebral oxygenation and as well as cerebral blood flow. Sampling procedures with identical sampling volumes are performed at a short (40 seconds) and a long (70 seconds) time intervall while changes of cerebral oxygenation are measured. The investigators hypothesise that slower sampling decrease changes in cerebral blood flow.