Search Results
Results 351 - 400 of 1598
< 3 4 5 6 7 8 9 10 11 12 13 >
Linder-Ganz E - - 2007
The clinical practice for minimizing the risk of pressure sores (PS) is to relief pressures under bony prominences of immobilized patients by changing their postures frequently. The US Department of Health advises to relief sitting pressures at least every 1 hour, and every 15 minutes for individuals who are body-abled. ...
Green A L - - 2007
In this chapter, we report that blood pressure can be increased or decreased depending on whether an electrode is in ventral or dorsal PAG. We also describe that it is theoretically possible to treat orthostatic hypotension. These are exciting developments not only because they provide an example of direct translational ...
Peralta C - - 2007
To compare frequency and degree of orthostatic hypotension (OH) in Parkinson's disease (PD) and Parkinson's disease with dementia (PDD) and its effect on attention and word fluency, blood pressure (BP) and heart rate changes during tilt were determined in 10 PD and 8 PDD patients. Attention and word fluency were ...
Ohlsson Bodil - - 2007
We have previously demonstrated that patients with Crohn's disease (CD) of long duration have signs of autonomic neuropathy. The aim of this study was to examine whether autonomic neuropathy is an early manifestation of CD, or a sign appearing late in the course. Twenty patients, median age 40 years, with ...
Deegan Brian M T BM Department of Electronic Engineering, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Galway, Ireland. - - 2007
Orthostatic Hypotension is a sudden drop in blood pressure upon assumption of upright posture. This drop in blood pressure is often results in symptoms such as dizziness, light-headedness, blurred vision, and syncope. Since 1986, tilt table testing has become widely used in the diagnosis of Orthostatic Hypotension. In this study, ...
Reisner A T AT Massachusetts General Hospital Dept. of Emergency Medicine, Boston, MA 02114, USA. - - 2007
Reduction in mean arterial pressure (MAP) is a late indictor of progressive circulatory pathology. Non-invasive monitoring methods that are superior indicators of circulatory compromise would be clinically valuable. With IRB approval, 21 healthy volunteers were subjected to progressive lower body negative pressure (LBNP) until the onset of presyncopal symptoms. We ...
Tachtsidis I - - 2007
We have previously used a continuous four-wavelength near-infrared spectrometer to measure changes in the cerebral concentrations of oxy-haemoglobin (Delta[HbO(2)] and deoxy-haemoglobin (Delta[HHb]) during head-up tilt in patients with primary autonomic failure. The measured changes in light attenuation also allow calculation of changes in the concentration of oxidized cytochrome-c-oxidase (Delta[(ox)CCO]), and ...
Morimoto Shigeto - - 2006
The object of this study was to examine blood pressure (BP) variability due to postural change in elderly hypertensive patients. The subjects studied were 154 elderly inpatients in a hospital for the elderly (48 male and 106 female; median age: 82 years), consisting of age- and sex-matched bedridden (n=39) and ...
Claydon Victoria E - - 2006
Individuals with spinal cord injury (SCI) are prone to orthostatic hypotension (OH). We aimed to develop a simple bedside test to evaluate autonomic control following chronic SCI, and to identify those most at risk of OH and cardiovascular dysfunction. We studied 14 subjects with cervical SCI, 11 with thoracic SCI, ...
Masuki Shizue - - 2007
Postural tachycardia syndrome (POTS) is characterized by excessive increases in heart rate (HR) without hypotension during orthostasis. The relationship between the tachycardia and anxiety is uncertain. Therefore, we tested whether the HR response to orthostatic stress in POTS is primarily related to psychological factors. POTS patients (n = 14) and ...
Taneja Indu - - 2007
Upright posture and lower body negative pressure (LBNP) both induce reductions in central blood volume. However, regional circulatory responses to postural changes and LBNP may differ. Therefore, we studied regional blood flow and blood volume changes in 10 healthy subjects undergoing graded lower-body negative pressure (-10 to -50 mmHg) and ...
Tuday Eric C - - 2007
Microgravity (microG)-induced orthostatic intolerance (OI) in astronauts is characterized by a marked decrease in cardiac output (CO) in response to an orthostatic stress. Since CO is highly dependent on venous return, alterations in the resistance to venous return (RVR) may be important in contributing to OI. The RVR is directly ...
Gasiorowska A - - 2006
Both intensive training and bed confinement impair orthostatic tolerance, however, moderate training may exert beneficial effect on cardiovascular adjustment to gravitational stimuli. It was hypothesized that moderate training attenuates effects of bed rest. To test this assumption 24 healthy male volunteers aged 20.8+/-0.9 yrs were subjected to 6 degrees head ...
Melby Daniel P - - 2007
BACKGROUND: Movement to upright posture may result in marked drop of blood pressure with susceptibility to injury from syncope and falls in patients with orthostatic hypotension. OBJECTIVE: The purpose of this study was to determine if increasing negative intrathoracic pressure by using an inspiratory impedance threshold device before change of ...
Singer Wolfgang - - 2006
The efficacy of current therapeutic measures in orthostatic intolerance (OI) varies among patients and is oftentimes unsatisfactory. New approaches to alleviate symptoms of OI are therefore clearly needed. Recent reports have demonstrated that acetylcholinesterase inhibition is effective in the treatment of orthostatic hypotension with the presumed mechanism of enhancing sympathetic ...
Fu Qi - - 2006
Vasomotor sympathetic activity plays an important role in arterial pressure maintenance via the baroreflex during acute orthostasis in humans. If orthostasis is prolonged, blood pressure may be supported additionally by humoral factors with a possible reduction in sympathetic baroreflex sensitivity. We tested the hypothesis that baroreflex control of muscle sympathetic ...
O'Leary D D - - 2007
Early analysis into the role of genetics on cardiovascular regulation has been accomplished by comparing blood pressure and heart rate in homozygous twins during unstressed, resting physiological conditions. However, many variables, including cognitive and environmental factors, contribute to the regulation of cardiovascular hemodynamics. Therefore, the purpose of this study was ...
Podoleanu Cristian - - 2006
OBJECTIVES: This study sought to assess the efficacy of compression bandage of legs and abdomen in preventing hypotension and symptoms. BACKGROUND: Progressive orthostatic hypotension can occur in elderly people during standing. METHODS: Twenty-one patients (70 +/- 11 years) affected by symptomatic progressive orthostatic hypotension underwent 2 tilt-test procedures, with and ...
Tsai Pei-Shan - - 2006
Vasovagal syncope refers to a reflex cardiovascular depression that gives rise to loss of consciousness with bradycardia and profound vasodilatation. This response commonly occurs during regional anesthesia, hemorrhage or supine inferior vena cava compression in pregnancy. The changes in circulatory response from the normal maintenance of arterial pressure to parasympathetic ...
Lahrmann H - - 2006
Orthostatic (postural) hypotension (OH) is a common, yet under diagnosed disorder. It may contribute to disability and even death. It can be the initial sign, and lead to incapacitating symptoms in primary and secondary autonomic disorders. These range from visual disturbances and dizziness to loss of consciousness (syncope) after postural ...
Kappel Franz - - 2007
This paper considers a model developed to study the cardiovascular control system response to orthostatic stress as induced by two variations of lower body negative pressure (LBNP) experiments. This modeling approach has been previously applied to study control responses to transition from rest to aerobic exercise, to transition to non-REM ...
Ichinose Masashi - - 2006
We tested the hypothesis that arterial baroreflex (ABR)-mediated beat-to-beat control over muscle sympathetic nerve activity (MSNA) is progressively modulated as orthostatic stress increases in humans, but that this control becomes impaired just before the onset of orthostatic syncope. In 17 healthy subjects, the ABR control over MSNA (burst incidence, burst ...
Fessel Joshua - - 2006
Orthostatic hypertension--a rise in blood pressure upon assuming upright posture-is an underappreciated and understudied clinical phenomenon. There is currently no widely agreed-upon definition of clinical orthostatic hypertension, the current definitions being operational within the context of particular studies. The underlying pathophysiology is thought to involve activation of the sympathetic nervous ...
Pathak Atul - - 2006
Blood pressure disorders are highly prevalent in the course of Parkinson's disease (PD). They relate to autonomic failure and are frequently associated with orthostatic hypotension, postprandial hypotension and supine hypertension. Supine hypertension, which may concern up to 50% of patients with PD and autonomic failure, is driven by residual sympathetic ...
Freitas J - - 2007
Orthostatic intolerance (OI) syndromes are frequent and share symptoms like dizziness and orthostatic syncope. Their pathophysiology however seems to be different. The aim of our work was to evaluate autonomic and hemodynamic behaviour in patients with familial amyloidotic polyneuropathy and neurally mediated syncope in supine position and after acute orthostatic ...
Gibbons Christopher H CH Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, - - 2006
To investigate the prevalence, symptoms, and neurophysiologic features of delayed orthostatic hypotension (OH). Blood pressures (BP) were measured at 1-minute intervals on 230 patients during 60 degrees head-up tilt for 45 minutes and standing for 5 minutes. OH was defined as a sustained fall in BP (>or=20 mm Hg systolic ...
Krassioukov A V - - 2006
Prospective assessment of cardiovascular parameters in individuals with spinal cord injury (SCI) in response to harness application and postural changes including orthostatic stress. To evaluate arterial blood pressure and heart rate (HR) with and without harness application during sitting, supine, and standing positions in able-bodied and SCI individuals. Measurements were ...
Shibasaki Manabu M Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, 7232 Greenville Ave., Dallas, TX 75231, - - 2006
Given the large increase in cutaneous vascular conductance (CVC) during whole-body heat stress, this vascular bed is important in the regulation of blood pressure during orthostatic stress. In this thermal state, changes in CVC are reported to be due to withdrawal of active vasodilator activity. The purpose of this study ...
Cutuk Adnan - - 2006
The purpose of this study is to assess cardiovascular responses to lower body positive pressure (LBPP) and to examine the effects of LBPP unloading on gait mechanics during treadmill ambulation. We hypothesized that LBPP allows comfortable unloading of the body with minimal impact on the cardiovascular system and gait parameters. ...
Wilson Thad E TE Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, and Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, 7232 Greenville Ave., Dallas, TX 75231, - - 2006
Orthostatic tolerance is reduced in the heat-stressed human. This study tested the following hypotheses: 1) whole body heat stress reduces cerebral blood velocity (CBV) and increases cerebral vascular resistance (CVR); and 2) reductions in CBV and increases in CVR in response to an orthostatic challenge will be greater while subjects ...
Naschitz Jochanan E - - 2006
OBJECTIVE: To assess the frequency of different orthostatic hypotension (OH) patterns in patients having supine hypertension with OH ('SHOH') versus patients with OH and normal supine blood pressure ('OH alone'); and to relate OH patterns with outcomes on head-up tilt. METHODS: Consecutive patients with nonspecific dizziness were studied with a ...
Green Alexander L - - 2006
OBJECTIVE: Electrical stimulation of the midbrain is known to influence blood pressure in animals. In humans, it is used for the treatment of chronic neuropathic pain. Our aim was to assess whether orthostatic hypotension can be successfully treated with deep brain stimulation of the periventricular/periaqueductal gray areas in humans. METHODS: ...
Mayer Antje F - - 2006
Previous studies suggest that neuronal norepinephrine transporter function may regulate the distribution of sympathetic activity among blood vessels, heart, and kidney; we tested the functional relevance in humans. Sixteen healthy men (26+/-1 years) ingested 8 mg of the selective norepinephrine reuptake transporter inhibitor reboxetine or a matching placebo on 2 ...
Krediet C T Paul - - 2006
Vasovagal syncope is the most common cause of transient loss of consciousness, and recurrent vasovagal fainting has a profound impact on quality of life. Physical countermaneuvers are applied as a means of tertiary prevention but have so far only proven useful at the onset of a faint. This placebo-controlled crossover ...
Convertino Victor A - - 2006
BACKGROUND: Breathing through an impedance threshold device (ITD) might prove effective as a countermeasure against post-spaceflight orthostatic hypotension since it increased blood pressure (BP) and cardiac output in supine human subjects. OBJECTIVE: We tested the hypothesis that spontaneous breathing through an ITD would attenuate the reduction in stroke volume and ...
Berry Narelle M - - 2006
BACKGROUND: The cardiovascular system is highly adaptable to sustained +Gz acceleration. Little is known as to whether the cardiovascular system can adapt to acute, repetitive +Gz exposures. This study tested the hypothesis that the cardiovascular system would adapt to repeated orthostatic challenges in a single session. METHODS: Over a 70-min ...
Momen Afsana - - 2006
Renal circulatory adjustments to stress contribute to blood pressure and volume regulation. Both handgrip (HG) and disengagement of baroreflexes with lower body negative pressure (LBNP) can engage the sympathetic nervous system (SNS). However, the effect of simultaneous HG and LBNP on the renal circulation in humans is not known. Eighteen ...
Murphy Dennis J - - 2006
INTRODUCTION: Methods most commonly used for detecting susceptibility to orthostatic hypotension in humans include head-up tilt and the application of lower body negative pressure (LBNP). The objective of this study was to evaluate the use of LBNP for detecting drug-induced changes in susceptibility to orthostatic hypotension in conscious monkeys (Macaca ...
Duschek Stefan - - 2006
Alterations in cortical activation processes due to chronic low blood pressure were investigated. In 40 hypotensive subjects and 40 normotensive controls, the contingent negative variation (CNV), induced by a constant foreperiod reaction time task, was assessed at nine scalp sites (F3, Fz, F4, C3, Cz, C4, P3, Pz, P4). Additionally, ...
Wang Xue - - 2006
INTRODUCTION: Recent studies show that cardiorespiratory variables are nonlinearly coupled. In the present study, we tested the feasibility of using bispectral analysis to estimate changes in nonlinear phase coupling. METHODS: We stimulated chemo- and baro-reflexes by switching inspired gas between air and air with 5% CO2 added during supine and ...
Naschitz J E - - 2006
The clinical syndrome of supine hypertension associated with orthostatic hypotension (OH) in given individuals is recognized by specialists, but is underdiagnosed in the community. The objective of this study was to assess supine hypertension associated with hypotensive reactions on head-up tilt (SH-HRT) among patients evaluated for nonspecific dizziness. Consecutive patients ...
Mattace-Raso Francesco U S - - 2006
OBJECTIVE: To investigate whether arterial stiffening, one of the characteristics of the aging vascular system, is associated with orthostatic hypotension. DESIGN: Cross-sectional data of a cohort study in elderly men and women. PARTICIPANTS: We investigated the relationship between arterial stiffness and orthostatic hypotension within the framework of the Rotterdam Study, ...
Raffai Gábor - - 2006
Microgravity and simulated microgravity may cause cardiovascular deconditioning, but mechanisms of instantaneous responses to inverse-orthostasis are not studied. Hence, we investigated transient and steady state cardiovascular changes by combining the tilt technique with cardiovascular telemetry. Normotensive and NO-deprived hypertensive Wistar rats were used to analyze responses of mean arterial blood ...
Guo Hong - - 2006
We sought to determine whether cerebral autoregulation (CA) is compromised during orthostatic stress superimposed with systemic hypotension. Transient systemic hypotension was produced by deflation of thigh cuffs previously inflated to suprasystolic pressure, combined with or without lower body negative pressure (LBNP). Cardiac output (CO) decreased from a baseline of 5.0+/-0.5 ...
Cohen Eytan - - 2006
The study sought to determine the duration of standing needed to detect most cases of orthostatic hypotension (OH) in the emergency room (ER) and to correlate OH with symptoms, hospitalization and survival. Patients attending a tertiary-center ER within a 2-month period underwent orthostatic tests after 1, 3 and 5 min ...
Mathias Christopher J - - 2006
The spinal cord is essential for normal autonomic nervous system regulation of the cardiovascular system as the preganglionic neurons controlling the heart and blood vessels originate in the thoracolumbar spinal segments. The site and extent of a spinal cord injury determine the degree of autonomic involvement in cardiovascular dysfunction after ...
Binzoni Tiziano - - 2006
The interest in, and the need for effective measures to be used in screening, diagnosis, and the follow-up of skeletal pathologies is growing markedly. This paper proposes a completely new and non-invasive technique allowing the study of the human tibia bone marrow (BM) haemodynamics with a time resolution of 1 ...
Vijayalakshmi P - - 2006
There are very few reports on the acute cardiovascular responses to head-down tilt of more than 30 degrees on blood pressure (BP) and heart rate (HR) in human subjects. The aim of the present study was to determine the BP and HR response to five minutes of 30 degrees, 60 ...
Tan Maw Pin - - 2006
Falls in older people can be caused by underlying cardiovascular disorders, either because of balance instability in persons with background gait and balance disorders, or because of amnesia for loss of consciousness during unwitnessed syncope. Pertinent investigations include a detailed history, 12-lead electrocardiography, lying and standing blood pressure, carotid sinus ...
Janský L - - 2006
The aim of this study was to ascertain whether repeated local cooling induces the same or different adaptational responses as repeated whole body cooling. Repeated cooling of the legs (immersion into 12 degrees C water up to the knees for 30 min, 20 times during 4 weeks = local cold ...
< 3 4 5 6 7 8 9 10 11 12 13 >