Search Results
Results 301 - 350 of 1595
< 2 3 4 5 6 7 8 9 10 11 12 >
Thijs Roland D - - 2007
We evaluated the use of strain gauge plethysmography (SGP) for the assessment of orthostatic fluid shifts during head up tilt (HUT). Subjects wore a parachute harness fixed to the tilt table to avoid muscle tension in the lower limbs during HUT. 22 Healthy subjects (9 women) were tilted for 5 ...
Alexandrova N P - - 2007
Effects of central hypervolemia on respiratory function and compensatory capabilities of the respiratory system were studied in the anesthetized, vagally intact or vagotomized rats. Central hypervolemia was induced by a head-down tilt on -30 degree rotation. The tilt evoked an elevation of central venous pressure (from -2+/-0.4 cmH2O to 3.9+/-0.8 ...
Krediet C T Paul - - 2007
IOH (initial orthostatic hypotension) comprises symptoms of cerebral hypoperfusion caused by an abnormally large transient MAP (mean arterial pressure) decrease 5-15 s after arising from a supine, sitting or squatting position. Few treatment options are available. In the present study, we set out to test the hypothesis that LBMT (lower ...
Claybaugh John R - - 2007
INTRODUCTION: Hyperbaria-induced diuresis is accompanied by decreased basal and stimulated release of arginine vasopressin (AVP) and decreased blood volume possibly contributing to the reported orthostatic intolerance. Since hyperosmolality is not a consistent finding, the explanation of blood volume reduction at hyperbaria must involve an osmotic component to the diuresis. Investigations ...
Mehlsen Jesper - - 2008
AIMS: Cardioinhibitory syncope (CS) is a neurally mediated response causing bradycardia or asystole. This study reports on changes in blood pressure, heart rate variability (HRV), and ECG patterns before and after syncope with asystole. METHODS AND RESULTS: Thirty-five patients with CS and a matched control group were submitted to 60 ...
Porta C - - 2008
OBJECTIVE: To analyse the influence of breathing activity on cerebrovascular dynamics during presyncope. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: 38 subjects developing neurocardiogenic syncope (syncope group), and 61 age-matched control subjects with negative tilt. INTERVENTIONS: Middle cerebral artery mean blood flow velocity (MCFV), continuous non-invasive blood pressure (BP), end-tidal ...
Deegan B M T - - 2007
Orthostatic hypotension (OH) is a clinical condition, which frequently results in symptoms such as syncope, dizziness during standing, weakness, blurred vision and fatigue. It is defined as a sustained drop in blood pressure exceeding 20 mmHg systolic or 10 mmHg diastolic occurring within 3 min of assuming upright posture, and ...
Gupta Vishal - - 2007
Orthostatic hypotension is a common problem among elderly patients, associated with significant morbidity and mortality. While acute orthostatic hypotension is usually secondary to medication, fluid or blood loss, or adrenal insufficiency, chronic orthostatic hypotension is frequently due to altered blood pressure regulatory mechanisms and autonomic dysfunction. The diagnostic evaluation requires ...
Maggi R - - 2007
Syncope is a transient, self-limited loss of consciousness, usually leading to falling. The underlying mechanism is a transient global cerebral hypoperfusion. Since there are many causes of syncope, a specific treatment cannot be administered without knowing of the exact mechanism responsible of loss of consciousness. Drugs are ineffective. The main ...
Wilson T E - - 2007
Central venous pressure (CVP) provides information regarding right ventricular filling pressure, but is often assumed to reflect left ventricular filling pressure. It remains unknown whether this assumption is correct during thermal challenges when CVP is elevated during skin-surface cooling or reduced during whole-body heating. The primary objective of this study ...
Ramsey Michael W - - 2007
The purpose of this investigation was to determine mean arterial pressure (MAP) and regional vascular conductance responses in young and aged Fisher-344 rats during orthostatic stress, i.e., 70 degrees head-up tilt (HUT). Both groups demonstrated directionally different changes in MAP during HUT (young, 7% increase; aged, 7% decrease). Vascular conductance ...
Fischer D - - 2007
This study tested the hypothesis that cardiovascular and hormonal responses to lower body negative pressure (LBNP) would be altered by 4-h head down bed rest (HDBR) in 11 healthy young men. In post-HDBR testing, three subjects failed to finish the protocol due to presyncopal symptoms, heart rate was increased during ...
Vaddadi Gautam - - 2007
Postural syncope is a transient loss of consciousness secondary to a reduction in cerebral blood flow and is typically precipitated by standing. It is the commonest cause of recurrent transient loss of consciousness. Recurrent unexplained postural syncope is most often due to one of the five disorders of circulatory control: ...
Choi Yong Seon - - 2007
OBJECTIVE: During one-lung ventilation, surgical positions significantly affect deterioration of oxygenation, and the lateral decubitus position is superior in preventing dangerous hypoxemia compared with the supine position. However, additional head-down tilt causes more compression of the dependent ventilated lung by the abdominal contents and may result in dangerous hypoxemia, as ...
Naschitz Jochanan E - - 2007
According to the 1996 consensus definition, orthostatic hypotension (OH) is diagnosed when a fall in systolic blood pressure of at least 20 mm Hg and/or diastolic blood pressure of at least 10 mm Hg within 3 min of standing is recorded. The elements of orthostatic blood pressure drop that are ...
Hoeldtke Robert D - - 2007
The purpose of this study was to determine whether autonomic neuropathy and the postural tachycardia syndrome can be treated with octreotide LAR (Long Acting Release). This was an open-label pilot project. Protocol 1 Patients with autonomic neuropathy (n = 4) were given increasing doses of octreotide LAR once a month ...
Deegan B M T - - 2007
AIMS: Orthostatic hypotension (OH) is a common condition, which is defined as a reduction in systolic blood pressure of >or=20 mmHg or diastolic blood pressure of >or=10 mmHg within 3 min of orthostatic stress. Utilizing total peripheral resistance (TPR) and cardiac output (CO) measurements during tilt-table testing (Modelflow method), we ...
Chan Gregory S H - - 2007
OBJECTIVE: Traditional vital signs such as heart rate (HR) and blood pressure (BP) are often regarded as insensitive markers of mild to moderate blood loss. The present study investigated the feasibility of using pulse transit time (PTT) to track variations in pre-ejection period (PEP) during progressive central hypovolaemia induced by ...
Schoffer Kerrie L - - 2007
There is limited evidence for the treatment of orthostatic hypotension in idiopathic Parkinson's disease. The objective of this study was to determine the efficacy of three treatments (nonpharmacological therapy, fludrocortisone, and domperidone). Phase I assessed the compliance, safety, and efficacy of nonpharmacological measures. Phase II was a double-blind randomized controlled ...
Petrofsky Jerrold - - 2007
BACKGROUND AND METHODS: Twenty-two subjects with type II diabetes and 30 control subjects participated in a 1-year study to examine the effect of rosiglitazone on heart rate variability at rest and the blood pressure, heart rate, and blood flow changes during a change in body position from horizontal to the ...
Ramírez-Marrero Farah A - - 2007
We evaluated the association between cardio-vagal baroreflex sensitivity (BRS; assessed with modified Oxford technique) and catecholamine response to 5 min 60 degrees head-up tilt (HUT) in 46 young healthy adults. HUT increased HR, mean arterial pressure, and NE (P < 0.05 for all). BRS was negatively correlated with NE response ...
Oka Hisayoshi - - 2007
We assessed the relations of visual hallucinations (VH) to cardiovascular autonomic dysfunction in patients with Parkinson's disease (PD). The subjects were 37 patients without VH (VH(-)) and 31 with VH (VH(+)). Autonomic function was evaluated on the basis of cardiac 123-radioiodinated metaiodobenzylguanidine (123I-MIBG) uptake and hemodynamic testing with Valsalva maneuver. ...
Karemaker John M - - 2007
In 2 ESA-cosmonauts we compared the 24-hr profiles in blood pressure (BP) and heart rate (HR) to those that we had observed in an earlier head-down tilted (HDT) bed rest study. In view of the lack of gravitational stress, an attenuated profile was expected, as in HDT. To obtain a ...
Beavers K R - - 2007
Twenty-four (24) healthy women from 25-40 years of age underwent orthostatic tolerance tests consisting of passive tilt and lower body negative pressure before and after completing 60-days of continuous -6 degree head down tilt bed rest (HDBR). Prior to HDBR, participants were assigned to one of three groups: control, exercise ...
Dorogovtsev V N - - 2007
Gravitation plays the important role in a pathogeny of the essential hypertension (EH). Modifications of hydrostatic pressure during body position changes, related to gravitational action, produce the significant hemodynamics shifts. Discordance of the orthostatic hemodynamics reactions with gravitational action can lead to orthostatic hypotension or proceed without any clinical signs ...
Sheldon Robert S - - 2007
BACKGROUND: Transient bradycardic hypotensive events occur in resting rabbits. If the hypotension is due to vasodepression, these events may be a model for vasovagal syncope. OBJECTIVES: To determine whether these events are responses to brief stimuli and whether the hypotensive episodes are solely due to rapid-onset bradycardia. METHODS: Rabbits were ...
Nishimura Naoki - - 2007
We investigated the effect of change in intrathoracic pressure by total body negative pressure (TBNP) or positive pressure (TBPP) on thermoregulatory responses during -6 degree head-down bed rest (HDBR). Eight healthy male subjects participated to three of the following interventions in a randomised sequence: 1) HDBR, 2) HDBR with TBNP ...
Broskey Justin - - 2007
A significant fraction of astronauts experience postflight orthostatic intolerance (POI) during 10-min stand tests conducted on landing day. The average time that nonfinishers can stand is about 7 min. This phenomenon, including the delay in occurrence of presyncope, was studied with a five-compartment model of the cardiovascular system incorporating compartments ...
Zamir M - - 2007
The current view of neurogenic vasomotor control in skeletal muscle is based largely on changes in vascular bed resistance. The purpose of this study was to determine to what extent vascular bed compliance may also play a role in this regulation. For this purpose, pressure waveforms (Millar and Finometer) and ...
van der Velde Nathalie - - 2007
OBJECTIVE: The role of orthostatic hypotension in falls in older people is generally accepted. Because of the high degree of intra- and interobserver variability in conventional measurements of orthostatic hypotension, application of continuous measurement systems has been proposed. The clinical relevance of a blood pressure drop lasting one heartbeat, however, ...
Olgar S - - 2007
Midodrine hydrochloride is a potent peripherally-acting alpha1 agonist that is well absorbed and rapidly metabolized to its active metabolite. It has been used for the treatment of refractory syncope but has the important side effect of supine hypertension. A 10-year-old boy with severe symptomatic orthostatic hypotension was treated with midodrine. ...
Carter Jason R - - 2007
The purpose of this study was to examine the effect of dimenhydrinate on resting muscle sympathetic nerve activity (MSNA), the vestibulosympathetic reflex, and the baroreflexes. Sixteen subjects participated in two double-blinded studies that measured mean arterial pressure (MAP), heart rate (HR), and MSNA responses before and after oral administration of ...
Cooke William H - - 2007
INTRODUCTION: Vestibular activation of semicircular canals has been linked to increased activity of parasympathetic neurons and has been proposed as a contributing factor to orthostatic intolerance. However, the functional consequences of head yaw rotation during orthostasis on human autonomic function have not been documented. The purpose of this study was ...
Nowak Lorenz - - 2007
BACKGROUND: The pathophysiology of neurocardiogenic syncope is heterogeneous. This study aim was to analyze whether extended monitoring during tilt-table testing provided additional information on the hemodynamic and vegetative state prior to neurocardiogenic syncope. METHODS: This retrospective analysis is based on data of head-up tilt-table testing of 40 unselected consecutive patients ...
Sheriff Don D - - 2007
Tolerance to +G(z) gravitational stress is reduced when +G(z) stress is preceded by exposure to hypogravity (fraction, 0, or negative G(z)). For example, there is an exaggerated fall in eye-level arterial pressure (ELAP) early on during +G(z) stress (head-up tilt; HUT) when this stress is immediately preceded by -G(z) stress ...
Pugliatti Pietro - - 2008
Head-up tilt testing is an important tool in the diagnosis of syncope. Several different protocols are in use. We describe the case of a 70-year-old Italian woman admitted to our observation. The patient was in antihypertensive treatment with carvedilol and with a combination of lisinopril and hydrochlorothiazide. A simplified Italian ...
Kimmerly D S - - 2007
The cortical regions representing peripheral autonomic reactions in humans are poorly understood. This study examined whether changes in forebrain activity were associated with the altered physiological responses to lower body negative pressure (LBNP) following a single bout of dynamic exercise (POST-EX). We hypothesized that, compared with the nonexercised condition (NO-EX), ...
Nishiyasu Takeshi - - 2007
We tested the hypothesis that peripheral vascular responses (in the lower and upper limbs) to application of lower body positive pressure (LBPP) are dependent on the posture of the subjects. We measured heart rate, stroke volume, mean arterial pressure, leg and forearm blood flow (using the Doppler ultrasound technique), and ...
Iida Haruko - - 2007
The application of an orthostatic stress such as lower body negative pressure (LBNP) has been proposed to minimize the effects of weightlessness on the cardiovascular system and subsequently to reduce the cardiovascular deconditioning. The KAATSU training is a novel method to induce muscle strength and hypertrophy with blood pooling in ...
Esch Ben T A - - 2007
Lower body negative pressure (LBNP) is an established and important technique used to physiologically stress the human body, particularly the cardiovascular system. LBNP is most often used to simulate gravitational stress, but it has also been used to simulate hemorrhage, alter preload, and manipulate baroreceptors. During experimentation, the consequences of ...
Mihci Ebru - - 2007
PURPOSE: To assess the effects of the tilt test on cerebral blood flow velocity (CBFV), blood pressure, and heart rate in patients with Parkinson's disease (PD) without symptomatic orthostatic dysautonomia. METHODS: Thirty patients with idiopathic PD and 15 healthy controls were included. Mean middle cerebral artery blood flow velocity (CBFV) ...
Zhang Rong - - 2007
BACKGROUND AND PURPOSE: The underlying mechanisms for reductions in cerebral blood flow (CBF) during orthostasis are not completely understood. This study tested the hypothesis that sympathetic activation causes cerebral vasoconstriction leading to reductions in CBF during lower body negative pressure (LBNP). METHODS: CBF velocity, arterial pressure, and end-tidal CO(2) were ...
Wyller Vegard Bruun - - 2007
Hemodynamic dysfunction is documented in chronic fatigue syndrome (CFS). This study was conducted to investigate cardiovascular responses to orthostatic stress in adolescents with CFS, using a novel procedure for tilt-table testing. A total of 27 adolescents with CFS and 33 healthy control subjects with equal age and gender distribution underwent ...
Møller Søren - - 2007
In cirrhosis, arterial vasodilatation leads to central hypovolemia and activation of the sympathetic nervous and renin-angiotensin-aldosterone systems. As the liver disease and circulatory dysfunction may affect baroreflex sensitivity (BRS), we assessed BRS in a large group of patients with cirrhosis and in controls who were all supine and some after ...
Steiner L A - - 2007
BACKGROUND: Compensated clinically silent hypovolaemia may lead to low cardiac output, hypoperfusion and ischaemia. We investigated the cardiovascular effects of simulated hypovolaemia to determine whether it caused mesenteric ischaemia detectable by gastric tonometry. METHODS: Thirteen healthy volunteers, aged 21-36 years, were investigated. Lower body negative pressure (LBNP) was used to ...
Fernandez-de-las-Peñas César - - 2007
DESIGN: Case-control, descriptive pilot study. OBJECTIVE: To describe the differences in the performance of the craniocervical flexion test (CCFT) between individuals with chronic tension-type headache (CTTH) and healthy controls. To assess the relationship between the CCFT, forward head posture, and several clinical variables related to the intensity and temporal profile ...
Pursiainen V - - 2007
OBJECTIVES: Parkinson's disease (PD) frequently affects both the extrapyramidal system and the autonomic nervous system (ANS), the latter also being sometimes disturbed by PD medications. Specifically selegiline is known to disturb cardiovascular ANS functions and may cause or enhance orthostatic hypotension. METHODS: In order to study the effect of the ...
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 ...
< 2 3 4 5 6 7 8 9 10 11 12 >