Active clinical trials for "Hypotension, Orthostatic"

Levodopa is a precursor of dopamine and is the treatment of choice to treat the motor symptoms of Parkinson's disease (PD); however, the effect of levodopa on cardiovascular autonomic function in PD is poorly understood. Orthostatic hypotension has been documented as a potential side effect of levodopa. As a result, clinicians may be reluctant to prescribe levodopa in patients with PD with neurogenic orthostatic hypotension (PD+OH), which leads to suboptimal management of motor symptoms. On the other hand, other studies failed to show any clear relationship between levodopa and orthostatic hypotension in patients with PD. Important limitations of prior studies include the lack of detailed investigation of baroreflex cardiovagal and sympathetic noradrenergic functions and the fact that the same patients were not tested on and off levodopa. The investigators propose to investigate the effects of levodopa on cardiovascular autonomic function in patients with PD+OH and PD without neurogenic orthostatic hypotension (PD-OH) by performing standardized autonomic testing in the same patients on and off levodopa.

The autonomic nervous system serves multiple regulatory functions in the body, including the regulation of blood pressure and heart rate, gut motility, sweating and sexual function. There are several diseases characterized by abnormal function of the autonomic nervous system. Medications can also alter autonomic function. Impairment of the autonomic nervous system by diseases or drugs may lead to several symptoms, including blood pressure problems (e.g., high blood pressure lying down and low blood pressure on standing), sweating abnormalities, constipation or diarrhea and sexual dysfunction. Because treatment options for these patients are limited. We propose to study patients autonomic failure and low blood pressure upon standing and determine the cause of their disease by history and examination and their response to autonomic testing which have already been standardized in our laboratory. Based on their possible cause, we will tests different medications that may alleviate their symptoms.

Study on orthostatic Hypotension in Parkinson's disease

This will be a Phase II single center, double-blind, randomized, placebo-controlled, efficacy study. Subjects will complete six visits. The first will be a screening visit. There will be four assessment visits: baseline, 2 weeks after the double-blinded trial begins, the end of the blinded trial, and after 4 weeks of washout. There will also be an additional randomization and medication dispensing visit immediately following the dose optimization period and preceding the double-blinded trial.

In the proposed study, the investigators examine in older adults with Type 2 diabetes the impact of beginning insulin therapy on the orthostatic drop in blood pressure as well as the response of arterial blood pressure and Doppler measures of cerebral blood flow during upright tilt. The investigators hypothesize that in older adults with Type 2 diabetes, the cardiovascular effects of insulin would precipitate or worsen orthostatic intolerance not present at baseline.

The purpose of this study is to determine whether Fipamezole is effective in the treatment of orthostatic hypotension and related symptoms in multiple system atrophy and Parkinson's disease.

Despite being studied less than half as frequently, autonomic dysfunction is a greater priority than walking again in spinal cord injury. One autonomic condition after spinal cord injury is orthostatic hypotension, where blood pressure dramatically declines when patients assume the upright posture. Orthostatic hypotension is associated with all-cause mortality and cardiovascular incidents as well as fatigue and cognitive dysfunction, and it almost certainly contributes to an elevated risk of heart disease and stroke in people with spinal cord injury. In addition, autonomic dysfunction leads to bladder, bowel, sexual dysfunctions, which are major contributors to reduced quality and quantity of life. Unfortunately, the available options for treating this condition, are primarily limited to pharmacological options, which are not effective and are associated with various side effects. It has been recently demonstrated that spinal cord stimulation can modulate autonomic circuits and improve autonomic function in people living with spinal cord injury. Neuroanatomically, the thoracolumbar sympathetic pathways are the primary spinal cord segments involved in blood pressure control. Recently, a pilot study has been published demonstrating that transcutaneous spinal cord stimulation of thoracolumbar afferents can improve cardiovascular function. However, some studies have shown that lumbosacral transcutaneous spinal cord stimulation can also elicit positive cardiovascular effects. Therefore, there is no consensus on the optimal strategy in order to deliver transcutaneous spinal cord stimulation to improve the function of the autonomic system, and it may be that lumbosacral (i.e. the stimulation site being used most commonly for restoring leg function is sufficient). Another key knowledge gap in terms of transcutaneous spinal cord stimulation is whether or not the current is directly or indirectly activating these spinal circuits. Last but not least, the effects of epidural spinal cord stimulation on the function of cardiovascular, bladder, bowel and sexual system in spinal cord injury have been investigated in no study yet. AIMS AND HYPOTHESES: Aim 1. To examine the effects of short-term (one session) transcutaneous spinal cord stimulation on the frequency and severity of episodes of orthostatic hypotension/autonomic dysfunction, and bladder, bowel, and sexual functions. These effects will be compared at two sites of stimulation. Hypothesis 1.1: Short-term transcutaneous mid-thoracic cord stimulation will mitigate the severity and frequency of orthostatic hypotension/autonomic dysfunction. Hypothesis 1.2: Lumbosacral transcutaneous spinal cord stimulation will improve bladder, bowel, and sexual functions. Aim 2. To examine the effects of long-term (one month) transcutaneous spinal cord stimulation on the severity and frequency of orthostatic hypotension/autonomic dysfunction. Hypothesis 2.1: Long-term stimulation of the mid-thoracic cord will result in sustained improvements in mitigated severity and frequency of orthostatic hypotension/autonomic dysfunction that is not dependent on active stimulation. Hypothesis 2.2: Long-term lumbosacral transcutaneous spinal cord stimulation will result in sustained improvements in bowel, bladder, and sexual function that is not dependent on active stimulation. Aim 3: To examine the effects of short-term (one session) epidural spinal cord stimulation on the severity and frequency of orthostatic hypotension/autonomic dysfunction, and bladder, bowel, and sexual functions. Hypothesis 3.1: Epidural spinal cord stimulation will mitigate the severity and frequency of orthostatic hypotension/autonomic dysfunction and improve bladder, bowel, and sexual function. Hypothesis 3.3: There is no significant difference between immediate effects of lumbosacral transcutaneous spinal cord stimulation and epidural spinal cord stimulation on bladder, bowel, and sexual function. For aim 1, 14 participants with spinal cord injury and no implanted electrodes on the spinal cord will be recruited. Participants will randomly receive one-hour stimulation under each of the two stimulation conditions in a crossover manner: Mid-thoracic and Lumbosacral. For aim 2, 28 individuals with spinal cord injury and no implanted electrode will be pseudo-randomized (1:1) to one of two stimulation sites. Participants will receive one-hour stimulation, five sessions per week for four weeks. Cardiovascular and neurological outcomes will be measured before the first stimulation session and after the last stimulation session. For aim 3, 4 participants with spinal cord injury with implanted electrodes on the spinal cord will be recruited to study the immediate effects of invasive epidural spinal cord stimulation. All outcomes will be measured in two positions: a) Supine, b) ~ 70° upright tilt-test. Additionally, bowel, bladder, and sexual functions in project 2 will be assessed weekly.

This study looks to characterize autonomic nervous system dysfunction after spinal cord injury and identify the potential role that transcutaneous spinal cord stimulation may play at altering neuroregulation. The autonomic nervous system plays key parts in regulation of blood pressure, skin blood flow, and bladder health- all issues that individuals with spinal cord injury typically encounter complications. For both individuals with spinal cord injury and uninjured controls, experiments will utilize multiple parallel recordings to identify how the autonomic nervous system is able to inhibit and activate sympathetic signals. The investigators anticipate that those with autonomic dysfunction after spinal cord injury will exhibit abnormalities in these precise metrics. In both study populations, transcutaneous spinal cord stimulation will be added, testing previously advocated parameters to alter autonomic neuroregulation. In accomplishing this, the investigators hope to give important insights to how the autonomic nervous system works after spinal cord injury and if it's function can be improved utilizing neuromodulation.

Vasoplegic syndrome is characterized clinically by reduced systemic vascular resistance and normal or increased cardiac output. It is principally observed in cardiovascular and orthopedic interventions and is characterized by a systemic inflammatory response with the inability of the vascular endothelial muscles to contract and a resistance to the action of vasoactive drugs. This event extends the length of stay in the critical care area due to the need of vasoactive drugs. The investigators aim to assess the standardized application of midodrine in postoperative patients without sepsis and need of vasoactive drugs in order to reduce the length of stay in critical care area and for extension in hospital.

Suspension syndrome refers to a potentially life-threatening condition that can occur in unconscious persons after prolonged suspension in a harness. To date, our understanding of the pathophysiology and appropriate treatment is based primarily on case reports and expert opinion. The main pathophysiological hypothesis implicates blood pooling in the lower extremity and lack of return via muscle pumping. However, a recent French study could not support this hypothesis. Other mechanisms, such as a central vagal reflex may play a role in the pathophysiology of suspension syndrome. The aim of this study is to better understand the pathophysiological basis of suspension syndrome and to develop practical recommendations for prevention and treatment.