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Results 401 - 450 of 1284
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Shykoff B E - - 2001
The diameter-pressure characteristics of dorsal hand veins previously have not been characterized. In this study, the effects of distending pressure with and without infused norepinephrine on diameter and compliance were observed. The elevation needed for venous collapse was measured, and the effects of baseline constriction on venous reactivity were assessed. ...
Kügler C - - 2001
The delicate interplay between the muscle-joint unit and intact venous valves is mandatory for normal venous blood return from the human leg. We have investigated the potential role of (1) muscle activity and joint mobility, and (2) anthropometric factors for peripheral venous pressure physiology. 20 healthy young subjects (10 males, ...
de Graaff J C - - 2001
Compression ultrasonography (CUS) falls short in the diagnosis of deep venous thrombosis in asymptomatic patients and thrombi limited to the calf veins. Alternatively, laser Doppler fluxmetry (LDF) may be useful for this purpose, as it can measure the peripheral vasoconstriction response upon an increase in venous pressure, which is hypothetically ...
Munis J R JR Section of Anesthesia for Neurosurgery, Department of General Anesthesiology, The Cleveland Clinic, Cleveland, Ohio 44195, USA. - - 2001
Neurosurgical patients undergoing either craniotomy or complex spine surgery are subject to wide variations in blood volume and vascular tone. The ratio of these variables yields a pressure that is traditionally measured at the superior vena cava and referred to as "central venous pressure" (CVP). We have investigated an alternative ...
Black I H - - 2000
OBJECTIVE: To determine whether central venous pressure measurements taken from a peripherally inserted central catheter (PICC) correlate with those from a centrally inserted central catheter (CICC). DESIGN: A pilot bench study followed by a prospective, non-blinded, clinical comparison. SETTING: A 16-bed medical coronary intensive care unit and a 30-bed surgical ...
Consolim-Colombo F M - - 2000
No study has been performed on reflexes originating from receptors in the heart that might be involved in the pathological lesions of Chagas' heart disease. Our study was undertaken to analyze the role of cardiopulmonary reflex on cardiovascular control in Chagas' disease. We studied 14 patients with Chagas' disease without ...
Burggraaf J - - 2000
AIMS: To determine the influence of the hand circulation on the determination of venous distensibility with venous occlusion plethysmography. METHODS: In a randomised study, duplicate measurements of forearm venous distensibility, with and without a wrist cuff, were made over occlusion periods of 3 and 12 min in eight volunteers. Treatments ...
Hoffman G M - - 2000
BACKGROUND: Reduction in oxygen delivery can lead to organ dysfunction and death by cellular hypoxia, detectable by progressive (mixed) venous oxyhemoglobin desaturation until extraction is limited at the anaerobic threshold. We sought to determine the critical level of venous oxygen saturation to maintain aerobic metabolism in neonates after the Norwood ...
Macé L - - 2000
To clarify the physiology of venous return (Q(vr)) in Fontan circulations, venous return conductance (G(vr)) and mean circulatory filling pressure (P(mcf)) were determined in pentobarbital sodium-anesthetized pigs. Relationships between Q(vr) and right (biventricular, n = 8) or left (Fontan, n = 8) filling pressures are described by straight lines with ...
Jakob S - - 2000
In intensive care, decision-making is often based on trend analysis of physiological parameters. Artifact detection is a pre-requisite for interpretation of trends both for clinical and research purposes. In this study, we developed and tested three methods of artifact detection in physiological data (systolic, mean and diastolic artery and pulmonary ...
Siekmann R - - 2000
BACKGROUND AND PURPOSE: The rete mirabile in swine has been proposed as an arteriovenous malformation (AVM) model for acute experimental studies through surgical creation of a large carotid-jugular fistula. This report describes two endovascular modifications to simplify the surgical creation and provides hemodynamic parameters for the AVM model. METHODS: An ...
Pang C C - - 2000
The venous system contains about 70% of the blood volume, and approximately 75% of the venous volume is in the small veins and venules. Veins play an active role in the control of cardiac output (CO) and blood pressure. Drugs that interfere with venous tone have profound effects on CO ...
Waddell L S - - 2000
Veterinary care has continued to advance by implementing more of the equipment and techniques that are commonly used in human medicine. This includes the placement of arterial catheters and pulmonary artery catheters and continuous monitoring of arterial pressure, central venous pressure, and pulmonary artery pressure. This article describes the technique ...
Nishinaka T - - 2000
We investigated changes in the cerebral metabolism with long-term reduced pulse pressure. Nine goats underwent pulsatile left heart bypass (LHB) for 2 weeks while awake, and nonpulsatile LHB was subsequently conducted for 4 weeks. The average pulse pressure during nonpulsatile LHB (13, 10, 11, and 11 mm Hg at the ...
Firstenberg M S - - 2000
The simplified Bernoulli equation relates fluid convective energy derived from flow velocities to a pressure gradient and is commonly used in clinical echocardiography to determine pressure differences across stenotic orifices. Its application to pulmonary venous flow has not been described in humans. Twelve patients undergoing cardiac surgery had simultaneous high-fidelity ...
Recek C - - 2000
Neovascularization is an important cause of venous reflux recurrence after high ligation of the long saphenous vein. The pathogenesis of this phenomenon is so far obscure. It is possible that a hemodynamic factor--a pressure gradient between the femoral vein and the residual long saphenous vein--could be the trigger initiating the ...
Fu Q - - 2000
In aged people, decreases in stroke volume and cardiac output during orthostatic challenge are less. It is suggested that the stiffness of blood vessels is greater in the elderly, blunting leg venous pooling and drop in central blood volume in an upright position. Leg venous hemodynamics plays an important role ...
Morita M - - 2000
The purpose of this study is to examine the efficiency of venous air removal with a new cardiopulmonary bypass (CPB) circuit design for conventional open-heart surgeries. A main concern with a closed circuit for open-heart surgeries is air entrainment into the venous line. A venous filter was placed proximal to ...
Neglen P - - 2000
The purpose of this study was to describe a method for measuring the deep venous pressure changes in the lower extremity and compare it with those obtained in the dorsal foot vein. After cannulation of the posterior tibial vein, a catheter with a pressure transducer in its tip was inserted ...
Labropoulos N - - 2000
OBJECTIVES: this study was designed to determine whether an intermittent pneumatic compression device (IPC) with an increased maximal inflation pressure, a decreased time to maximal pressure and a longer duration of compression would improve venous return compared to a standard IPC device. METHODS: thirty limbs in 15 volunteers without evidence ...
Pfister M - - 2000
Accessory hemodialysis equipment, including dialysis cannulas, usually lack controlled and independent testing before being introduced onto the market. The aim of this study is a prospective comparison of a newly designed curved-tip dialysis cannula with a standard dialysis cannula of the same size from the same manufacturer. Fifteen chronic dialysis ...
Bergan J J - - 2000
Non-elastic compression has been used to treat venous insufficiency of the lower extremities for more than 150 years. The best and most recognized example is the Unna boot. When compared with other dressings, the Unna boot has performed as well as or better than other forms of compression. While the ...
Delis K T - - 2000
OBJECTIVE: intermittent pneumatic compression (IPC) of the foot (IPC(foot)), calf (IPC(calf)) or both (IPC(foot+calf)) augments calf inflow, and improves the walking ability and peripheral haemodynamics of claudicants (IPC(foot), IPC(foot+calf)), largely due to venous outflow enhancement. This cohort study, using direct pressure measurements in healthy limbs, determines the optimal combination of ...
Naschitz J E - - 2000
Prior observations showed that the consequences of venous hypertension depend not only on the magnitude of the venous pressure but also on the efficiency of compensatory mechanisms that protect against the effects of excessive pressures on the microcirculation. Pulsatile venous insufficiency (PVI) associated with severe tricuspid regurgitation (TR) provides the ...
van Geest A J - - 2000
BACKGROUND: Medical elastic compression stockings are widely used in venous diseases. Their effects on the venous system have been shown in the past. Up to now, little is known about the slope or stiffness factor of stockings. OBJECTIVE: To evaluate the effect of different slope and stiffness factors of medical ...
Fronek A - - 2000
The purpose of this study was to develop a physiologic method to measure outflow and inflow from the lower extremities and thus to quantify the degree of venous valvular insufficiency and venous obstructive disease. Calibrated photoplethysmography was used in combination with passive changes in hydrostatic pressure, by leg elevation followed ...
Iwama H - - 2000
PURPOSE: The aim of this study was to examine whether intermittent pneumatic compression (IPC) increases peripheral circulation locally in order to assess the use of IPC for prevention of deep venous thrombosis. MATERIALS AND METHODS: Seventy adult patients receiving major gastrointestinal surgery were studied. On postoperative day 1, calf-length garments ...
Jellinek H - - 2000
To study the effect of positive airway pressure (Paw) on the pressure gradient for venous return [the difference between mean systemic filling pressure (Pms) and right atrial pressure (Pra)], we investigated 10 patients during general anesthesia for implantation of defibrillator devices. Paw was varied under apnea from 0 to 15 ...
Walsh J T - - 2000
Inferior vena caval pressures were measured in 60 patients undergoing cardiac catheterization and compared with central venous pressure from within the right atrium. Mean pressures within the abdominal inferior vena cava were essentially the same as mean right atrial pressure, suggesting that the inferior vena cava provides a useful safe ...
Wecht J M - - 2000
The effects of autonomic disruption and inactivity were studied on the venous vascular system. Forty-eight subjects, 24 with spinal cord injury (SCI) and 12 sedentary and 12 active able-bodied controls, participated in this study. Peripheral autonomic data were obtained to estimate sympathetic vasomotor control [low-frequency component of systolic blood pressure ...
Hahn T L - - 2000
PURPOSE: To evaluate the role of intercellular adhesion molecule 1 (ICAM-1) in cutaneous leukocyte trapping in venous disease, we used our rodent model of venous hypertension (VH). MATERIALS AND METHODS: VH was created in adult rats by ligation of the inferior vena cava, bilateral common iliac veins, and bilateral common ...
Binzoni T - - 2000
The purpose of this study is to develop a new method for the measurement in humans of the compliance of the microvascular superficial venous system of the lower limb by near-infrared spectroscopy (NIRS). This method is complementary to strain-gauge plethysmography, which does not allow compliance between deep and superficial venous ...
Blackman D J - - 2000
BACKGROUND: Although nitric oxide (NO) is known to play an important part in the regulation of arterial tone, little is known about its role in veins. The aim of this study was to investigate the role of basal and stimulated NO activity in the regulation of tone of the human ...
Milhaud D - - 2000
Dural puncture with corticosteroid could be a predisposing factor for cerebral venous thrombosis (CVT). A 35-year-old woman using oral contraception was treated with corticosteroid epidural infiltration for L5 radiculalgia. The following day a postural headache developed and accidental dural puncture was suspected. Four days later, she presented with fever and ...
Motoyama S - - 2000
This study investigates whether the pressure parameters obtained from the Swan-Ganz catheter (SGC) accurately reflect the circulating blood volume just after en bloc resection of the thoracic esophagus with regional lymph node dissection. It is well known that this operation induces severe hemodynamic changes and although the pressure parameters obtained ...
Mehlsen J - - 2000
Cardiac output is largely controlled by venous return, the driving force of which is the energy remaining at the postcapillary venous site. This force is influenced by forces acting close to the right atrium, and internally or externally upon the veins along their course. Analogue models of the venous system ...
Piccoli A - - 2000
OBJECTIVE: To assess the relationship between central venous pressure values and bioelectrical impedance vector analysis (BIVA), which may be used as complementary methods in the bedside monitoring of fluid status. DESIGN: Cross-sectional evaluation of a consecutive sample. SETTING: Intensive care unit of a university hospital. PATIENTS: One hundred and twenty-one ...
Miyasaka Y - - 2000
BACKGROUND: The present study was designed to determine whether there is a physiological explanation for the predisposition of patients with certain angiographic characteristics to haemorrhage from cerebral arteriovenous malformations (AVMs). METHODS: Intra-operative measurement of feeding artery pressure (FAP) and intravascular pressures in the draining venous system [draining vein pressure (DVP) ...
Constant J - - 2000
External jugulars are not reliable as an indication of right atrial pressure because of their passage through two right angles and also because they are often not visible. The top level of internal jugular pulsations which are transmitted to the skin of the neck serves as a pulsation manometer. A ...
Jünger M - - 2000
The elevated ambulatory pressure in the peripheral venous system of chronic venous insufficiency (CVI) patients manifests itself not only in the form of disturbed macrocirculation but also and particularly in microangiopathic changes. For this reason, it is closely correlated with trophic disorders of the skin and can ultimately lead to ...
Durán W - - 2000
One of the hallmarks of chronic venous insufficiency (CVI) is an elevated venous pressure. However, no direct link at the cellular and molecular levels between venous hypertension and actual tissue damage in CVI has been established. Evidence for generations of an inflammatory reaction and several molecular alterations in the development ...
Santoro A - - 2000
Convective transport across the dialysis membrane has long been known to be a good alternative to diffusion. Among the advantages of haemofiltration over conventional haemodialysis is a better cardiovascular stability. Haemofiltration has a more physiological response to fluid removal than haemodialysis: (i) blood volume may be better preserved, especially in ...
Fronek A - - 2000
In view of the resemblance of exercise-induced plethysmographic changes with those obtained by direct venous pressure measurement, we decided to use a combination of photoplethysmography (PPG) and hydrostatic pressure calibration to determine the PPG/pressure relationship. A standard foot dorsiflexion exercise involving stepwise position changing was performed which induced hydrostatic pressure ...
Ipsiroglu O S - - 1999
Up until recently the evaluation of CVR (analysis of pulsatility) had been a priority in Doppler sonography. In preterm and term infants with open fontanels and sutures this information is restricted despite its value in extreme situations. Continuous Doppler sonography allows a new approach to monitoring pathophysiologic processes. In connection ...
Ead D N - - 1999
The purpose of this study was to obtain objective information on the necessity of invasive anesthetic monitoring during radical prostatectomy. We reviewed retrospectively the charts of 257 patients undergoing radical prostatectomy on an established pathway which did not include the intraoperative use of an arterial line or central venous catheter. ...
Buhs C L - - 1999
We evaluated the effects of wearing 20 to 30 mm Hg gradient thigh-length stockings during daily activity on the lower leg venous system. Twenty-one healthy women volunteers, aged 39 +/- 12 years, were examined. One subject was clinical class 4, one was class 2, two were class 1, and the ...
Ben-Haim M - - 1999
The application of laparoscopic technique has gained popularity in the past decade. Numerous studies have qualified and quantified the systemic impact of acutely elevated intra-abdominal pressure during pneumoperitoneum at time of laparoscopy. The major hemodynamic effects are increased central venous pressure, increased systemic vascular resistance and systemic hypertension. Reductions in ...
Boland R A - - 1999
Swelling, or increased volume, secondary to venous congestion is thought to be a factor in some upper limb conditions. This study aimed to establish a safe, easily applied method of inducing a transitory increase in forearm and hand volume that could be used as a symptom provocation test for upper ...
Wideman R F RF - - 1999
We evaluated the hypothesis that venous congestion (increased venous volume), as reflected by venous hypertension (increased venous pressure), can arise when the right ventricle is unable to elevate the pulmonary arterial pressure sufficiently to propel the cardiac output through an anatomically inadequate or inappropriately constricted pulmonary vasculature. Changes in venous ...
Tevaearai H T - - 1999
Blood return into the cardiotomy reservoir is usually reduced when a cardiopulmonary bypass (CPB) is initiated through a peripheral access, even if the tip of the venous cannula is pushed into the right atrium. A centrifugal pump can be placed on the venous line to increase the negative pressure. Surgery ...
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