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Sahni Manish - - 2005
Orthostatic hypotension is very common in the elderly. It increases morbidity and is an independant predictor of all cause mortality. It is defined as a fall in systolic blood pressure greater than 20 mm Hg or a fall in diastolic blood pressure greater than 10 mm Hg within 3 minutes ...
Russomano T T Microgravity Laboratory/IPCT-Pontifical Catholic University, Porto Alegre, RS, - - 2005
A headward fluid shift occurs during microgravity exposure, which causes the cardiovascular adaptive syndrome. Different countermeasures have been proposed to decrease its symptomatology, like the application of lower body negative pressure (LBNP). A LBNP box with an environment control system was developed, aiming to improve features of LBNP boxes used ...
Ouchi Yasuomi - - 2005
To investigate whether a physiological change in the orthostatic condition is associated with a deterioration of cerebrovascular and metabolic homeostasis in patients with neurocardiovascular compromises, we examined 10 patients with unilateral carotid artery occlusive disease (CVD), 6 CVD patients with coronary artery disease (CVDC), and 10 healthy subjects scanned twice ...
Stage Kurt Bjerregaard Bjerregaard - - 2005
From a clinical point of view, orthostatic hypotension is a significant side effect during antidepressant treatment, particularly in the case of tricyclic antidepressants (TCAs). This prospective, randomized clinical trial evaluated the effects of clomipramine and moclobemide on orthostatic blood pressure during treatment for depression. One hundred and fifteen depressed inpatients, ...
Gupta S C - - 2005
This study anus at determining the effect of transmyringeal ventilation on Eustachian tube functions. Seventy ears clinically diagnosed as having otitis media with effusion or grade I and II retraction of pars-tensa of tympanic membrane were treated with antiallergics, decongestants, mucolytics, and antibiotics as required for maximum upto three months. ...
Lu Hongbing H Member, IEEE, Department of Computer Application, Fourth Military Medical University, Xi'an, Shaanxi 710032, China. phone: 86-29-83374837; fax: 86-29-82534555; e-mail: - - 2005
The aim of this study is to investigate the upper limit of protection afforded by various protective equipment and techniques that used in combination and used individually. A multi-element, nonlinear mathematical model, which was previously used to produce cardiovascular response to +Gz stress and protection afforded by anti-G suits, was ...
Gorelik Oleg - - 2005
Information about orthostatic hypotension (OH) among elderly patients hospitalized for acute conditions in short-term facilities is scarce. Many older inpatients carry various predisposing factors for OH. However, its existence goes frequently unrecognized. In this context, first morning standing up following admission for an acute disease may be dangerous. The aim ...
Hoshide Satoshi - - 2005
To investigate the impact of arterial properties on orthostatic blood pressure (BP) dysregulation in older hypertensives, orthostatic BP dysregulation, a common phenomenon in elderly hypertensives, is associated with target organ damage and falls. However, the mechanism of orthostatic BP dysregulation remains unclear. The pulse wave velocity (PWV), related arterial stiffness, ...
Naylor Justine M - - 2005
BACKGROUND AND PURPOSE: Isolated head-down postural drainage is assumed to acutely load the cardiovascular system. Consequently, it is considered a relative contraindication in the presence of severe cardiovascular disease. Evidence demonstrating that the head-down manoeuvre as used by physiotherapists does significantly load the cardiovascular system is lacking. The present study ...
van Dijk Nynke - - 2005
A 33-year old male patient, with Marfan's syndrome, reported symptoms of orthostatic intolerance and fatigue as a longstanding problem. Orthostatic cardiovascular examination showed poor orthostatic tolerance, with a rise in heart rate and a fall in arterial blood pressure and cerebral blood flow velocity. Self-discovered physical counterpressure manoeuvers improved symptoms, ...
Tachtsidis Ilias - - 2005
The cardiovascular and cerebrovascular responses to head-up postural change are compromised in pure autonomic failure (PAF) patients because of sympathetic denervation. The aim of this study was to characterize the rate of change of systemic mean blood pressure (MBP) and cerebral haemodynamics in response to passive posture changes. Nine PAF ...
Hao Wei-Ya - - 2004
INTRODUCTION: The development of orthostatic hypotension (OH) is complex and multi-factorial. Previous simulation work indicates that myocardial contractility depression (MCD) may increase OH when there is a total blood volume decrease. This paper hypothesized that MCD increased OH in both humans with and without decrease in blood volume. METHODS: A ...
Chang Angela T - - 2004
OBJECTIVE: To investigate the effect of standing with assistance of the tilt table on ventilatory parameters and arterial blood gases in intensive care patients. DESIGN: Consecutive sample. SETTING: Tertiary referral hospital. PARTICIPANTS: Fifteen adult patients who had been intubated and mechanically ventilated for more than 5 days (3 subjects successfully ...
Young T M - - 2004
BACKGROUND: Oral ingestion of water increases seated blood pressure in patients with chronic autonomic failure by mechanisms that remain unclear. As orthostatic hypotension is common in chronic autonomic failure, and is not always adequately controlled by medication, the potential benefits of water ingestion on standing blood pressure were studied in ...
Romano Salvatore M - - 2004
OBJECTIVES: The aim of this study was to noninvasively define the hemodynamic profile characterizing the early response to tilting. BACKGROUND: The mechanisms causing orthostatic intolerance have not been fully elucidated. Usually, patients undergoing tilt test are studied in a time-consuming way. Moreover, the test can cause discomfort to the patient ...
Hinghofer-Szalkay Helmut - - 2004
INTRODUCTION: The purpose of this study was to identify the combinations of head down tilt (HDT) and lower body negative pressure (LBNP) that would counterbalance each other's effects on cardiovascular and endocrine variables to produce a "neutral point" (NP). METHODS: We conducted 8 30-min experiments in 14 normotensive subjects (2 ...
Ichinose Masashi - - 2004
We tested the hypothesis that orthostatic stress would modulate the arterial baroreflex (ABR)-mediated beat-by-beat control of muscle sympathetic nerve activity (MSNA) in humans. In 12 healthy subjects, ABR control of MSNA (burst incidence, burst strength, and total activity) was evaluated by analysis of the relation between beat-by-beat spontaneous variations in ...
Otto M E B - - 2004
The first minutes of the time course of cardiopulmonary reflex control evoked by lower body negative pressure (LBNP) in patients with hypertensive cardiomyopathy have not been investigated in detail. We studied 15 hypertensive patients with left ventricular dysfunction (LVD) and 15 matched normal controls to observe the time course response ...
Fu Qi - - 2004
BACKGROUND: We tested the hypothesis that individual variability in orthostatic tolerance is dependent on the degree of neural and vasomotor reserve available for vasoconstriction. METHODS AND RESULTS: Muscle sympathetic nerve activity (MSNA) and hemodynamics were measured in 12 healthy young volunteers during 60 degrees head-up tilt (HUT), followed by a ...
Mori R L RL Univ. of Pittsburgh, School of Medicine, Dept. of Otolaryngology, Rm. 519, Pittsburgh, PA 15213, - - 2005
The vestibular system participates in cardiovascular regulation during postural changes. In prior studies (Holmes MJ, Cotter LA, Arendt HE, Cas SP, and Yates BJ. Brain Res 938: 62-72, 2002, and Jian BJ, Cotter LA, Emanuel BA, Cass SP, and Yates BJ. J Appl Physiol 86: 1552-1560, 1999), transection of the ...
Hainsworth Roger - - 2004
Syncope or near-syncope is a not uncommon effect of gravitational or other stresses and it occurs when cerebral blood flow falls to below about half the normal value. It is not necessarily abnormal, and individuals who are usually asymptomatic show the same reaction if a stress is sufficiently great to ...
Evans Joyce M - - 2004
INTRODUCTION: Exposure to spaceflight or simulations of microgravity reduce human postflight orthostatic tolerance. Exercise training and volume loading can reduce associated losses of plasma volume and muscle strength, but are not successful in maintaining postflight orthostatic tolerance. A preliminary study (16) indicated that short bouts of artificial gravity (AG) training ...
Bogert Lysander W J - - 2004
INTRODUCTION: In patients with recurrent syncope, monitoring of intra-arterial pressure during orthostatic stress testing is recommended because of the potentially sudden and rapid development of hypotension. Replacing brachial arterial pressure (BAP) by the non-invasively obtained finger arterial pressure (FinAP) has advantages because catheterization in itself may provoke a syncope. OBJECTIVE: ...
Bjarnegård N - - 2004
AIMS: The mechanical properties of arteries play a major role in the regulation of blood pressure and cardiac performance. The effect of sympathetic stimulation on the mechanical properties of the proximal brachial artery was analysed in 18 healthy volunteers, nine young (25 +/- 2 years) and nine elderly (69 +/- ...
Cybulski G - - 2004
The aim of the study was to compare stroke volume (SV), ejection time (ET) and pre-ejection period (PEP) measurements obtained using a central haemodynamics ambulatory monitoring device based on impedance cardiography (ICG), in supine and tilted positions (60 degrees), with pulsed Doppler echocardiography as a non-invasive reference method. The Holter-type ...
Mathias C J - - 2004
Water drinking recently has been shown to raise blood pressure in normal subjects and in patients with autonomic failure who have orthostatic hypotension. However, in normal young subjects, ingestion of approximately 500 ml has no pressor effect; but in older subjects there is an increase in blood pressure. An even ...
Weisbrod Cara J - - 2004
We compared haemodynamic and peripheral vasomotor responses to lower body negative pressure (LBNP) in cardiac transplant recipients who had undergone bicaval anastomoses, involving right atrial deafferentation (-RA), and the conventional procedure in which some atrial baroreceptor afferents remain intact (+RA). We measured mean forearm blood flow (FBF) responses using Doppler/ultrasound ...
Gisolf Janneke - - 2004
OBJECTIVES: We set out to determine the effect of sublingual nitroglycerin (NTG), as used during routine tilt testing in patients with unexplained syncope, on hemodynamic characteristics and baroreflex control of heart rate (HR) and systemic vascular resistance (SVR). BACKGROUND: Nitroglycerin is used in tilt testing to elicit a vasovagal response. ...
Sahul Zakir H - - 2004
BACKGROUND: Tachypacing has been suggested to compensate for drop in blood pressure as a technique to improve symptoms in patients with severe orthostatic hypotension secondary to autonomic dysfunction. To date, however, no randomized controlled studies have been performed to validate the approach. METHODS AND RESULTS: Six patients with severe orthostatic ...
Pitt Marjorie S - - 2004
Crouching then standing induces large changes in arterial blood pressure. Ingestion of carbohydrate and water are known to have contrasting effects on cardiovascular control in patients with various forms of autonomic dysfunction. We tested the hypothesis that, in patients with attacks of posturally related (neurogenic or vasovagal) syncope, postural maneuvers ...
Edwards Michael R - - 2004
Electrodermal activity (EDA) increases during arousal, emotional stimuli or thermoregulatory sweating and is sometimes apparent in unfiltered ECG recordings. We hypothesized that changes in EDA precede any change in blood pressure (BP) or cerebral blood velocity (CBV) observed at syncope. Data from 70 patients referred for recurrent syncope were retrospectively ...
Singh K - - 2004
Systolic time intervals (STI) are sensitive indices of myocardial function. The present study was conducted to evaluate the effect of orthostatic stress on STI before and after 70 degrees head up tilt (HUT) in rabbits. Electrocardiogram (ECG), phonocardiogram and carotid arterial pulse were recorded simultaneously on four channel polyrite (INCO). ...
Balocchi R - - 2004
Orthostatic intolerance is the most serious symptom of cardiovascular deconditioning induced by microgravity. We have showed that in symptomatic subjects the baroreflex control of sinus node is affected by short term simulated microgravity. At present the influence of the respiration on the cardiovascular system in this condition is not clear. ...
Young Trudie - - 2004
Manual repositioning of patients by nursing staff is a recognised technique for preventing pressure ulcer formation. The 30 degree tilt is a method of positioning patients that, in the laboratory setting, reduced the contact pressure between the patient and the support surface. A randomised controlled trial was used to examine ...
Maurer Mathew S - - 2004
BACKGROUND: Orthostatic hypotension (OH) is traditionally defined as a decline in systolic or diastolic blood pressure of >20 or >10 mm Hg, respectively, after 1 or 3 minutes of upright posture. OH is common in the elderly, but has not been consistently demonstrated to be an independent risk factor for ...
Claydon V E - - 2004
Orthostatic tolerance is a measure of the ability to prevent hypotension during gravitational stress. It is known to be dependent on the degree of vasoconstriction and the magnitude of plasma volume, but the possible influence of packed cell volume (PCV) is unknown. High altitude residents have high haematocrits and probably ...
Yamazaki Fumio - - 2004
To test the hypothesis that tolerance to central hypovolemic stress is diminished with a reduced sensitivity of cardiac baroreflex in young and old men, twenty-four healthy elderly male subjects (67.5+/-0.9 yrs) and 24 young male subjects (22.4+/-0.4 yrs) underwent a 21 min bout of ramped lower body negative pressure (LBNP) ...
Smit Adrianus A J - - 2004
The aim of this study was to investigate in patients with neurogenic orthostatic hypotension the mechanism and usefulness of abdominal compression to increase standing blood pressure. In three protocols, 23 patients underwent abdominal compression. Protocol 1 evaluated in a 40-60 degrees head-up-tilt position, the effect of abdominal compression on caval ...
Platts Steven H - - 2004
Many astronauts exhibit post-spaceflight orthostatic hypotension due to inadequate norepinephrine release when in an upright posture. We hypothesized that an alpha1-adrenergic agonist, midodrine, would be an effective countermeasure. A female astronaut, who had problems with postflight orthostatic hypotension after a previous flight, consumed 10 mg midodrine after a subsequent flight, ...
Yanagiya Yusuke - - 2004
A bionic baroreflex system (BBS) is a computer-assisted intelligent feedback system to control arterial pressure (AP) for the treatment of baroreflex failure. To apply this system clinically, an appropriate efferent neural (sympathetic vasomotor) interface has to be explored. We examined whether the spinal cord is a candidate site for such ...
Convertino Victor A - - 2004
We measured various hemodynamic responses and muscle sympathetic nerve activity (MSNA) in human subjects during a graded lower-body negative pressure (LBNP) protocol to test the hypotheses that: (1) reduced stroke volume (SV) is linearly related to increased MSNA; and (2) the onset of symptoms of impending cardiovascular collapse is associated ...
Sun Biao - - 2004
This study was designed to clarify whether simulated microgravity-induced differential adaptational changes in cerebral and hindlimb arteries could be prevented by daily short-period restoration of the normal distribution of transmural pressure across arterial vasculature by either dorsoventral or footward gravitational loading. Tail suspension (Sus) for 28 days was used to ...
O'Leary Deborah D - - 2004
Beat-by-beat estimates of total peripheral resistance (TPR) can be obtained from continuous measurements of cardiac output by using Doppler ultrasound and noninvasive mean arterial blood pressure (MAP). We employed transfer function analysis to study the heart rate (HR) and vascular response to spontaneous changes in blood pressure from the relationships ...
Harinath Kasiganesan - - 2004
OBJECTIVES: To evaluate effects of Hatha yoga and Omkar meditation on cardiorespiratory performance, psychologic profile, and melatonin secretion. SUBJECTS AND METHODS: Thirty healthy men in the age group of 25-35 years volunteered for the study. They were randomly divided in two groups of 15 each. Group 1 subjects served as ...
Lee Kichang - - 2004
The reproducibility of heart rate variability (HRV) measures during graded lower body negative pressure (LBNP) have not been studied in sufficient detail. Active college age men (n=14) underwent an orientation exposure and two trials of graded LBNP to presyncope or -100 mmHg, separated by 1 week. Heart rate, stroke volume ...
Ichinose Masashi - - 2004
We tested the hypothesis that in humans, carotid-baroreflex dynamic responses (evaluated by examining the time course of the carotid-baroreflex-induced alterations in muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP) and heart rate (HR)) would be altered during mild orthostatic stress in ways that serve to limit orthostatic hypotension. ...
Seymour Roger S - - 2004
Changes in orientation in a gravitational field markedly alter the patterns of blood pressure and flow in animals, especially tall or long ones such as giraffes or snakes. Vertical orientation tends to reduce blood flow and pressure in the head for two major reasons. First, the increased vertical blood column ...
Hannerz Jan - - 2004
OBJECTIVE: To investigate the mechanisms behind the increase of chronic tension-type headache during head-down tilt. BACKGROUND: The pathophysiology of chronic tension-type headache is unknown. DESIGN AND METHODS: Ten patients suffering from chronic tension-type headache and 10 age- and sex-matched controls were studied with respect to pain intensity and alterations in ...
Cui Jian - - 2004
The purpose of this project was to test the hypothesis that increases in muscle sympathetic nerve activity (MSNA) during an orthostatic challenge is attenuated in heat-stressed individuals. To accomplish this objective, MSNA was measured during graded lower body negative pressure (LBNP) in nine subjects under normothermic and heat-stressed conditions. Progressive ...
Gotoh Taro Miyahara - - 2004
To examine acute hemodynamic responses to microgravity (microG) in the head, we measured carotid artery pressure (CAP) and jugular vein pressure (JVP) to calculate cephalic perfusion pressure (CPP = CAP - JVP) and recorded images of microvessels in the iris to evaluate capillary blood flow velocity (CBFV) and capillary diameter ...
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