The Effects of Normalizing Blood Pressure on Cerebral Blood Flow in Hypotensive Individuals With...
Spinal Cord InjuryAutonomic Dysreflexia8 moreDysregulation of blood pressure (BP), secondary to decentralized autonomic nervous system (ANS) control of the cardiovascular system, often results in chronic hypotension and orthostatic hypotension (OH) in persons with spinal cord injury (SCI), particularly in those with high cord lesions (i.e., above T6). While most hypotensive individuals with chronic SCI remain asymptomatic and do not complain of symptoms associated with cerebral hypoperfusion, evidence of reduced resting cerebral blood flow (CBF) has been reported in association with low systemic BP in the SCI and non-SCI populations. Reduced CBF in hypotensive individuals may lead to cognitive dysfunction, and we reported significantly impaired memory and marginally impaired attention processing in hypotensive individuals with SCI compared to a normotensive SCI cohort. Furthermore, we found that CBF was not increased during cognitive testing in individuals with SCI, which may contribute to impaired cognitive function compared to non-SCI controls. Although asymptomatic hypotension may have an adverse impact on cognitive function and quality of quality of life (QOL) clinical management of this condition is extremely low. In fact, we reported that while nearly 40% of Veterans with SCI were hypotensive, less than 1% carried the diagnosis of hypotension or were prescribed an anti-hypotensive medication. The discrepancy between incidence and treatment of asymptomatic hypotension in the SCI population may relate to a paucity of treatment options which are supported by rigorous clinical trials documenting safe and effective use of anti-hypotensive therapy on BP, CBF and cognitive function. We hypothesize these study medications may increase systolic blood pressure to the normal range and improve cerebral blood flow velocity. Results and conclusions will not be removed from the record.
Hypotension Probability Index in Anesthesia
Hip DiseaseHypotension2 moreThe aim of the study is to investigate the value of the Hypotension Probability Index in reducing intraoperative hypotension in patients with primary hip replacement. The measurement of the blood pressure was and is of great interest for the treating physician/anesthesiologist to optimize the peri- and postoperative patients outcome. The non-invasive measurement can scale the blood pressure but not from heartbeat-to-heartbeat, what results in a loss of information. The invasive measurement by a placed catheter in an artery shows the blood pressure with information about the pulse wave form, the ascending angle, and makes it possible to detect hemodynamic changes in a way the non-invasive blood pressure measurement is lacking. The additional informations of the monitoring and a
Clinical Effect of Ampreloxetine (TD-9855) for Treating Symptomatic nOH in Subjects With Primary...
Symptomatic Neurogenic Orthostatic HypotensionA Phase 3 study to evaluate efficacy, safety, and tolerability of ampreloxetine (TD-9855) in subjects with primary autonomic failures (MSA, PD, or PAF) and symptomatic nOH with up to 4 weeks of treatment.
The Exercise Response to Pharmacologic Cholinergic Stimulation in Myalgic Encephalomyelitis / Chronic...
Myalgic Encephalomyelitis/Chronic Fatigue SyndromeChronic Fatigue Syndrome7 moreMyalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS), otherwise known as Chronic fatigue syndrome (CFS) or myalgic encephalomyelitis (ME), is an under-recognized disorder whose cause is not yet understood. Suggested theories behind the pathophysiology of this condition include autoimmune causes, an inciting viral illness, and a dysfunctional autonomic nervous system caused by a small fiber polyneuropathy. Symptoms include fatigue, cognitive impairments, gastrointestinal changes, exertional dyspnea, and post-exertional malaise. The latter two symptoms are caused in part by abnormal cardiopulmonary hemodynamics during exercise thought to be due to a small fiber polyneuropathy. This manifests as low biventricular filling pressures throughout exercise seen in patients undergoing an invasive cardiopulmonary exercise test (iCPET) along with small nerve fiber atrophy seen on skin biopsy. After diagnosis, patients are often treated with pyridostigmine (off-label use of this medication) to enhance cholinergic stimulation of norepinephrine release at the post-ganglionic synapse. This is thought to improve venoconstriction at the site of exercising muscles, leading to improved return of blood to the heart and increasing filling of the heart to more appropriate levels during peak exercise. Retrospective studies have shown that noninvasive measurements of exercise capacity, such as oxygen uptake, end-tidal carbon dioxide, and ventilatory efficiency, improve after treatment with pyridostigmine. To date, there are no studies that assess invasive hemodynamics after pyridostigmine administration. It is estimated that four million people suffer from ME/CFS worldwide, a number that is thought to be a gross underestimate of disease prevalence. However, despite its potential for debilitating symptoms, loss of productivity, and worldwide burden, the pathophysiology behind ME/CFS remains unknown and its treatment unclear. By evaluating the exercise response to cholinergic stimulation, this study will shed further light on the link between the autonomic nervous system and cardiopulmonary hemodynamics, potentially leading to new therapeutic targets.
Norepinephrine Transporter Blockade, Autonomic Failure (NETAF)
Neurogenic Orthostatic HypotensionDrug therapy for patients suffering from autonomic failure and neurogenic orthostatic hypotension are scarce and not effective. If left untreated, these patients have the highest risk of syncope, falls and fall-related injuries. The proposed study will determine the clinical benefit of a commercially available drug, atomoxetine, to reduce symptoms associated with neurogenic orthostatic hypotension in patients with autonomic failure.
Cardiac Output Changes During Hyperbaric and Isobaric Bupivacaine in Patients Undergoing Cesarean...
Cardiac OutputHypotension2 moreSpinal block leads to the reduction of systemic vascular resistance (SVR) which may effect the cardiac output. Ngan Kee et al. has showed that spina block with 0.5% hyperbaric bupivacaine for Cesarean section combined with intravenous infusion norepinephrine had higher cardiac output than those who received phenylephrine
The Hemodynamic Effects of Vasopressin in Patients With Fontan Physiology
HypotensionFontan PhysiologyThe goal of this study is to evaluate if vasopressin can elevate systemic arterial blood pressures without having a significant effect on pulmonary arterial pressures. Because patients who have undergone Fontan procedures rely on low pressures across the pulmonary vascular bed to maintain cardiac output, vasoactive agents that concomitantly increase systemic and pulmonary pressures may have a deleterious effect in this specific patient population. Hypothesis: In patients with Fontan physiology, vasopressin will increase systemic BP by 20% above baseline, without increasing the transpulmonary gradient.
Midodrine for Improving Hemodynamics After Spinal Anesthesia
Hypotension After Spinal AnesthesiaNeuraxial blockade such as spinal anaesthesia can cause severe hypotension due to pharmacological sympathectomy resulting in potential deleterious consequences for the patient. Prevention of this spinal anaesthesia induced hypotension is of utmost importance. Techniques currently in use for preventing hypotension include intravenous fluid prehydration, sympathomimetic drugs, and physical methods such as leg bindings and compression stockings. Midodrine is a direct acting α1-adrenoceptor agonist which causes venous and arterial vasoconstriction through stimulation of α1- receptors located in the vasculature. The aim of this study is to evaluate the efficacy and safety of prophylactic midodrine use with preoperative fluid hydration before spinal anesthesia in the prevention of hypotension in patients undergoing elective orthopedic surgery. We hypothesize that intraoperative hypotension would be less in patients given midodrine and intravenous fluid prehydration preoperatively before spinal anesthesia.
Hypotension Prediction With HPI Algorithm During Major Gynecologic Oncologic Surgery
Intraoperative HypotensionHemodynamic Instability1 moreIntraoperative hypotension (IOH) is a rather common event during general surgery, with variable incidence that ranges between 5 and 99% based on the definition used. It is associated to significant complications including acute renal failure, myocardial damage, stroke and overall increased mortality, reason why the prevention and the reduction of hypotensive events through an appropriate proactive approach can potentially improve the patient's outcome. The Hypotension Prediction Index (HPI) is an algorithm derived from the analysis of the arterial waveform and it is expressed as an absolute value from 0 to 100. It has been demonstrated that the HPI is able to predict the occurrence of hypotensive events of patients undergoing major surgery under general anesthesia, providing also a guide for the appropriate treatment based on further calculated secondary hemodynamic variables that estimate patient's preload, cardiac contractility and afterload. Aim of this prospective randomized study is to compare the incidence of IOH during major gynecologic oncologic surgery among two groups of patients receiving standard hemodynamic monitoring versus HPI monitoring. The primary hypothesis is that hemodynamic management HPI-guided reduces the incidence, entity and duration of intraoperative hypotensive events, defined as mean arterial pressure (MAP) lower than 65 mmHg lasting more than one minute.
Tilt-Table Study of the Clinical Efficacy of Midodrine in Symptomatic Orthostatic Hypotension
Orthostatic HypotensionThe purpose of this study is to determine whether midodrine works against the symptoms of orthostatic hypotension caused by being on a tilt table.