View clinical trials related to Cerebral Hemodynamics.
Filter by:Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Some researchers proposed that the dysregulated response or organ dysfunction can be lessened by reducing the stress response, which further reduce complication and mortality rates of sepsis. Dexmedetomidine is alpha adrenergic receptor agonist, presenting sympatholytic action in certain parts of the brain with anxiolytic, sedative, and pain killing effects. In the experiments of sepsis animal model, dexmedetomidine have been proved to improve serum lactate clearance and the microcirculation. Dexmedetomidine may inhibit inflammation, as it enhances the activity of the immune system while reducing its systemic reaction and lowering cytokine concentrations. There are also evidences in clinical trials with definite safety that dexmedetomidine reduced inflammation, reduced vasopressor requirements and improved organ function. The beta antagonist esmolol has been proposed as a therapy to lower heart rate, thereby improving diastolic filling time, and improving cardiac output, resulting in a reduction in vasopressor support. A recent meta-analysis of 8 randomized studies using esmolol suggested that the 32% risk ratio decreased 28-day mortality, and a meta-analysis of 7 studies using esmolol in patients with sepsis and septic shock was associated with 32% lower 28-day mortality. However, the effect of anti-stress drugs on cerebral hemodynamics is unknown. In this study, investigators are going to apply the technique of transcranial Doppler to assess the reaction of cerebral blood flow in anti-stress group and control group.
One of the challenges in pediatric anesthesiology is to ensure adequate cerebral perfusion pressure to prevent cerebral ischemia or hyperemia from pressure-passive perfusion. However, there is no optimal tool for longitudinally monitoring cerebral perfusion under general anesthesia (GA). In addition, the safe limits of blood pressure that maintains adequate cerebral perfusion in infants and children are not clear. Furthermore, patients with neurological impairments may have impaired cerebral auto-regulation (CA) function which may associated with functional outcomes. To address the critical public health issues associated with the safe use of general anesthesia in during neurosurgery, monitoring cerebral perfusion and oxygenation continuously during the peri-operative period. The investigators have pioneered a novel technology, diffuse correlation spectroscopy (DCS), to optically measure cerebral blood flow (CBF) non-invasively and demonstrated that it is safe and practical as a bedside CBF monitor in the NICU. Blood flow is distinct from blood oxygenation, but both are important for brain health. Clinical near infrared spectroscopy (NIRS) devices are available to monitor oxygenation by light absorption, but CBF must be monitored by light scattering, which is only available with research DCS devices. While the physical principles of the methods are different, the sensors for both techniques are very similar. The investigators have therefore combined DCS with advanced frequency-domain NIRS (FDNIRS) in a single device to simultaneously monitor cerebral tissue oxygen saturation (cStO2), blood volume (CBV), CBF and oxygen metabolism (CMRO2), which cannot be monitored with existing clinical devices. The investigators have previously shown that these measures are far more sensitive than cStO2 alone in several infant brain pathologies. In this study, the investigators aim to test the feasibility of integrating the FDNIRS-DCS technology into perioperative monitoring to study cerebral hemodynamics and oxygen metabolism continuously in children during general anesthesia and surgery. Additionally, the investigators will determine how anesthesia-related events affect cerebral hemodynamic instability and how anesthetic level correlates with CA functions in children.
The investigators are looking to determine the effects of PEMFs device on cerebral blood flow and cognition in healthy volunteers. Through in vitro tests and in vivo animal studies, the investigators have shown that at an extremely low flux density (strength) of 1 millitesla (mT) and with short exposures of 10 minutes a week, PEMFs can recapitulate many of the healthful benefits of exercise without imparting a mechanical stress on the tissues and cells. In the first-in-man study, 10 healthy volunteers were exposed to PEMFs for 6 weeks with 10 minutes of field exposure per week, and experienced an average increase of 30% in leg strength. No side effects were reported. In this study, the investigators aim to understand the cerebral effects of an exercise mimetic (PEMFs) via the muscle milieu.