Use of Accelerometer for Quantification of Neurogenic Orthostatic Hypotension Symptoms
Orthostatic; HypotensionNeurogenic5 moreThe objective of this study is to find a more objective and accurate way to assess the efficacy of the treatment for neurogenic orthostatic hypotension. For this purpose, the investigators will use an activity monitor to determine the amount of time patients spend in the upright position (standing and walking; upright time) during 1 week of placebo (a pill with no active ingredients) and 1 week of their regular medication for orthostatic hypotension (midodrine or atomoxetine at their usual doses). Total upright time (i.e. tolerance to standing and walking) will be compared between placebo and active treatment to test the hypothesis that it can be used to assess the efficacy of the treatment for orthostatic hypotension and whether this outcome is superior to the assessment of symptoms using validated questionnaires.
Effects of Midodrine and Droxidopa on Splanchnic Capacitance in Autonomic Failure
Autonomic FailurePure Autonomic Failure3 moreThe purpose of this study is to learn more about the effects of midodrine and droxidopa, two medications used for the treatment of orthostatic hypotension (low blood pressure on standing), on the veins of the abdomen of patients with autonomic failure. The study will be conducted at Vanderbilt University Medical Center, and consists of 2 parts: a screening and 2 testing days. The total length of the study will be about 5 days. About 34 participants will be screened for the study.
Hemodynamic Mechanisms of Abdominal Compression in the Treatment of Orthostatic Hypotension in Autonomic...
Orthostatic HypotensionPure Autonomic Failure2 moreCompression garments have been shown to be effective in the treatment of orthostatic hypotension in autonomic failure patients. The purpose of this study is to determine the hemodynamic mechanisms by which abdominal compression (up to 40 mm Hg) improve the standing blood pressure and orthostatic tolerance in these patients, and to compare them with those of the standard of care midodrine. The investigators will test the hypothesis that abdominal compression will blunt the exaggerated fall in stroke volume and the increase in abdominal vascular volume during head up tilt.
Histamine as a Molecular Transducer of Adaptation to Exercise
Postexercise HypotensionThis study is investigating the role of histamine in generating adaptation to exercise
Evaluation of the Early Use of Norepinephrine in Major Abdominal Surgery on Postoperative Organ...
NorepinephrineHypotension2 moreHemodynamic instability is frequent during surgery and intraoperative hypotension is associated with excess morbidity and excess mortality in high-risk patients. In major abdominal surgery the incidence of intraoperative hypotension remains high. For the past few years, some teams have proposed evaluating norepinephrine as a first-line drug in the presence of hypotension or even before hypotension occurs Thus in obstetrics, the preventive use of norepinephrine for cesareans performed under spinal anesthesia was associated with a reduction in the incidence of hypotension per operative without deleterious effect for the newborn or parturient. In the absence of any observed complications, several teams began to use noradrenaline prophylactically in other surgery. However, no study has demonstrated its benefit, particularly the term of surgical complication in abdominal surgery. The objective of this work is to assess the preventive use of norepinephrine in major abdominal surgery on the occurrence of intraoperative hypotension, postoperative organ dysfunction and postoperative medical and surgical complications.
Lower Body Muscle Pre-activation in Initial Orthostatic Hypotension
Orthostatic IntoleranceSyncope2 moreThis study is aimed primarily at providing a simple and effective form of treatment to reduce the symptoms of Initial Orthostatic Hypotension (IOH) and prevent syncope. We will first characterize the physiology of IOH, and then we will study four sit-to-stand maneuvers, each with a different stress tests to identify the role of sympathetic activity vs. simple muscle contraction in IOH. Then we will complete an additional two sit-to-stands with interventions designed to decrease the blood pressure drop (and hopefully symptoms) with initial stand. These consist of physical counter maneuvers, which may be a possible treatment that can be used to mitigate the drop in blood pressure (BP) seen in IOH during a stand and relieve presyncope symptoms.
Enhancing the Cardiovascular Safety of Hemodialysis Care (Dialysafe)
Kidney FailureEnd Stage Renal Disease3 moreThe purpose of this study is reduce episodes of intradialytic hypotension, low blood pressure during a hemodialysis session, in patients with End Stage Renal Disease (ESRD). Recruitment will take place on the clinic level rather than the patient level.
Leg Elevation to Prevent Hypotension During Labor
HypotensionLabor ComplicationWhen hypotension is related to epidural placement, this can occur within 15-60 minutes after placement. The purpose of this study is to build upon this preliminary work and to use a randomized controlled trial to examine the effectiveness of leg elevation in preventing hypotension among a larger sample of laboring women who receive an epidural analgesia. This study will use a randomized, non-blinded, controlled design with two arms: Arm 1: Patient will be put in a left tilt position with her hip on a wedge and both legs elevated on a peanut ball. She'll remain in this position for approximately 40 minutes. Arm 2: Patient will be put in a left tilt position with her hip on a wedge and no leg elevation. She'll remain in this position for approximately 40 minutes.
VBI-S for the Treatment of Hypotension in Hypovolemic Septic Shock Patients
Septic ShockSepsis1 moreThis study is being conducted to evaluate the safety and effectiveness of VBI-S in elevating the blood pressure of septic shock patients with absolute or relative hypovolemia.
Cardiovascular Effects of Exercise in Patients With Parkinson's Disease
Parkinson DiseaseOrthostatic HypotensionAbnormalities in the regulation of cardiovascular system due to autonomic nervous system (ANS) dysfunction may lead to a sudden decline in blood pressure (BP) upon standing, sitting or performing activities/exercises in patients with Parkinson's Disease (PD). This sudden decline in BP is known as 'orthostatic hypotension' (OH). OH may cause dizziness and/or black-outs, which may increase the risk of falls. As falls are potentially dangerous and disabling, it is important to prevent their occurrence. Keeping BP within normal range upon change of posture or with activities is therefore of great significance. Pooling of blood in the abdominal blood vessels may be one of the reasons for OH to happen. This research focuses on strengthening the weak abdominal muscles of the participants so that the compressive action of these muscles can help decrease such pooling. Therefore, the researchers hypothesize that strengthening the abdominal muscles shall prove to be helpful in controlling orthostatic hypotension by preventing a sudden decline in blood pressure of the participants upon assumption of upright posture. The secondary hypothesis is that there exists a significant difference in the response of the cardiovascular system to a variety of postures/activities/exercises when patients of PD having cardiovascular autonomic dysfunction are compared with patients of PD with normal ANS function. This study has two parts - stage 1 and stage 2. Only stage 2 is a randomized controlled trial. Stage 1 involves testing the functional integrity of the autonomic nervous system, and observation of the cardiovascular responses of the participants to different postures/activities/exercises and to the use of an abdominal binder (which is a compressive garment worn around the abdomen). Findings of stage 1 shall help the researchers better understand the cardiovascular abnormalities present in such patients at rest and with activity. Stage 2 involves strength training for the abdominal muscles that is to be done by the participant at her/his residence for a period of 3 months followed by a second round of autonomic function testing and observation of the cardiovascular responses to the use of abdominal binder. Findings of stage 2 shall help the researchers determine if strength training of the abdominal muscles can be a useful strategy to counter the cardiovascular abnormalities found in the participants during the testing in stage 1.