Search Results
Results 551 - 600 of 1277
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Tyberg J V - - 1996
We suggest a mechanism by which blood volume changes might explain the hypotension that, after space flight, often accompanies the return to normal gravity. Upon entering microgravity, peripheral veins may collapse and, because of volume redistribution, raise the pressure in the central venous compartment. After some time in space, homeostatic ...
Abu-Yousef M M - - 1996
OBJECTIVE: The purpose of this study was to determine if pulsatile flow in lower limbs as seen on venous Doppler waveforms correlates with increased right atrium pressure. MATERIALS AND METHODS: Of 429 patients who, over a 14-month period, underwent venous Doppler imaging of the lower limb to exclude deep venous ...
Simons P - - 1996
Oedema remains one of the most common causes of hand stiffness. Local venous return is intimately associated with oedema formation and management. To elucidate the underlying mechanisms of venous return, the venous pumping systems in the hand were objectively and quantitatively investigated using Doppler ultrasound, cadaveric dissection and venography. It ...
Veraart J C - - 1996
BACKGROUND: Although medical elastic compression stockings are widely used in venous diseases their effects on the venous system are still largely unclear. OBJECTIVE: To evaluate the pressure of these medical elastic compression stockings on the skin and their edema protective effects. METHODS: On 18 legs the interface pressure of the ...
Nalbantoglu U - - 1996
In this study, peripheral microcirculatory response to arterial and venous cannulation was studied. Eleven Sprague-Dawley rats were evaluated in two groups. Group I was the control group and received no cannulation (N = 6). After cremaster muscle isolation, the following parameters were evaluated at the microcirculatory level: vessel diameters, red ...
Tyberg J V - - 1996
The concept of left ventricular (LV) 'preload' has seemed simple and straightforward. Similarly, the capacitance function of the veins seemed to be defined, in spite of the fact that 'venous return' might be said to be increased in heart failure when it was obvious that cardiac output was substantially decreased. ...
Herts B R - - 1996
PURPOSE: To determine the feasibility of use of a power injector to deliver contrast material through central venous catheters for computed tomographic (CT) examinations. MATERIALS AND METHODS: Ioversol 240 and iothalamate meglumine 43% were separately injected through three 9.6-F Hickman catheters and three 10.0-F Leonard catheters with a power injector ...
Lui A S - - 1996
Nitroglycerine relaxes vascular smooth muscle and is routinely use to treat angina and congestive heart failure. However, in preliminary observations of severe heart failure patients, nitroglycerine did not dilate superficial veins, although the observations were made at the top of the distention-pressure relationship for superficial veins. Hence, the purpose of ...
Robinson R R - - 1996
BACKGROUND: Astronauts conducting extravehicular activities undergo decompression to a lower ambient pressure, potentially resulting in gas bubble formation within the tissues and venous circulation. Additionally, exposure to microgravity produces fluid shifts within the body leading to cardiovascular deconditioning. A lower incidence of decompression illness in actual spaceflight compared with that ...
Schiltenwolf M - - 1996
To confirm the hypothesis that venous congestion plays a role in idiopathic lunate necrosis (Kienböck's disease), intraosseous pressure in 12 normal and 12 necrotic lunates was measured. Intraosseous pressure in the capitate of 12 healthy subjects served as reference measurement. The intraosseous pressure was recorded in neutral position and 60 ...
Luckie A P - - 1996
OBJECTIVE: To assess the rate of change in the central retinal venous closing pressure in central retinal vein obstruction over time, and its relationship to visual acuity improvement and the development of rubeosis iridis. METHODS: Fifty patients presenting with central retinal vein obstruction of less than three months' duration, between ...
Petersen J - - 1996
Serum concentrations of rHuEPO were measured after injection into different sites within the blood lines in patients undergoing hemodialysis. The authors compared the venous port to venous drip chamber injection using two separate delivery systems and their associated blood lines (Cobe Centry 3 [CGH, Lakewood, CO] and Fresenius A2008 [Fresenius ...
Castini D - - 1996
This study was undertaken to elucidate the still debated question of the relationship between cardiac volume and QRS voltage amplitude. The authors studied 14 healthy men, aged 24-61 years (mean age, 41.2 +/- 12.1 years). They underwent a reduction in venous return, produced by simultaneously inflating sphygmomanometric cuffs placed around ...
Vicol C - - 1996
PURPOSE: The suitability of a rheolytic system for recanalization of aged venous thrombotic occlusions was tested in an animal experiment. METHODS: The system consists of a flush-suction catheter and a high-pressure liquid pump. Thrombosis was experimentally induced in 13 venous segments of 10 adult goats. RESULTS: After a mean period ...
Mayer S - - 1996
A solution algorithm yielding the pressure and flow-rate distributions for steady flow in an arbitrary, tree-like network is provided. Given the tree topology, the conductance of each segment and the pressure distribution at the boundary nodes, the solution is obtained from a simple recursion based on perfect Gauss elimination. An ...
Scott D A - - 1996
We evaluated the resistance to fluid infusion in the veins of 118 adult patients after intravenous catheter insertion prior to elective surgery. Hydraulic resistance in veins was defined as the slope of the pressure-flow relationship obtained by measuring venous pressure at several fluid flow rates. A resistance unit (RU) was ...
Buckey J C JC - - 1996
Gravity affects cardiac filling pressure and intravascular fluid distribution significantly. A major central fluid shift occurs when all hydrostatic gradients are abolished on entry into microgravity (microG). Understanding the dynamics of this shift requires continuous monitoring of cardiac filling pressure; central venous pressure (CVP) measurement is the only feasible means ...
Foldager N - - 1996
Based on the results of head-down simulation studies and the results of parabolic flights, the hypothesis was tested that central venous pressure (CVP) in humans increases during microgravity (weightlessness) compared with during the ground-based supine position. CVP was recorded with an intravascular pressure transducer in seven healthy humans during short ...
Nahum E - - 1996
OBJECTIVE: To determine the accuracy of mean continuous central venous pressure (CVP) measurements in the abdominal vena cava. DESIGN: We simultaneously measured the CVP at the superior vena cava or right atrium and at the abdominal vena cava or common iliac vein. The study was conducted at the pediatric intensive ...
Zamboni P - - 1996
OBJECTIVE: To assess the relationship between in vitro and in vivo venous compliance measurement. DESIGN: Prospective, blind study. MATERIALS AND METHODS: Patients affected by primary varicose veins and classified in accord with the new CEAP criteria (C2-6/S, Ep, AS1-4/p17-18, PR) underwent blind venous compliance measurements using two different methods. 1) ...
Mackay Z - - 1996
Normovolemic hemodilution with 3,5% polygeline was carried out in fourteen ASA (American Society of Anesthesiologists) Class-I patients, who had developed false aneurysms or arteriovenous fistulas following high velocity injury on limbs. At the end of surgical procedure volume of mean blood drained was 1400.00 +/- 194.46 ml, mean surgical blood ...
Joynt G M - - 1996
BACKGROUND: Complications can arise from standard intrathoracic central venous pressure (CVP) measurements in critically ill, mechanically ventilated patients. We have assessed the feasibility of catheterisation by the femoral route to measure CVP in the abdomen (ACVP). We compared measurements by the standard jugular or subclavian route (TCVP) with simultaneous ACVP ...
Hartog E A - - 1996
In eight mechanically ventilated, anaesthetized pigs weighing 10.3 +/- 0.8 kg (mean +/- SD) we studied the effect of the inflation time of the lung on the estimation of the mean systemic filling pressure (Psf) from the changes in venous return and central venous pressure during inflation of the lung. ...
Hausmann H - - 1996
BACKGROUND AND METHODS: In 21 patients intraoperatively receiving coronary revascularization, segments of the saphenous vein were prepared for aortocoronary bypass. Postoperatively, the endothelial intima was subjected to electron microscopy. Venous segments in which an intraluminal mean pressure of 263 mmHg +/- 52 mmHg had been measured during preparation were compared ...
Abdelmawla A H - - 1996
We have measured the diameter of the human dorsal hand vein (DHV) in situ and compared the venoconstrictor dose-response curves to locally infused noradrenaline at different venous congestion pressures using the DHV compliance technique. Congestion pressure was defined as the inflation pressure of a sphygmomanometer cuff on the ipsilateral upper ...
Payne S P - - 1996
OBJECTIVES: (1) To evaluate the full spectrum of venous skin damage with respect to ambulatory venous pressure. (2) To determine whether the ambulatory venous pressure/tourniquet test can be used to select patients for superficial venous surgery (eg. long or short saphenous stripping). DESIGN: Prospective study. SETTING: Vascular studies unit. MATERIALS ...
Reed R K - - 1996
The removal rate of high molecular weight (M(r) 3 x 10(6) [3H]hyaluronan has been measured in rabbit paw skin in control and during increased local venous pressure induced by ligation of the femoral vein. The increased venous pressure resulted in a 20% increase of interstitial volume at 4 h after ...
Karahalios D G - - 1996
Pseudotumor cerebri (PTC), or idiopathic intracranial hypertension, is a syndrome associated with multiple clinical conditions. We hypothesize that most if not all etiologies result in an increase in intracranial venous pressure as a final common pathway. We studied 10 patients with PTC. Five had dural venous outflow obstruction as demonstrated ...
Asgeirsson B - - 1996
Elevation of an organ above the heart reduces the arterial and venous hydrostatic pressures in proportion to the height of elevation. Intact autoregulation protects organs, such as the brain and skeletal muscle, from significant alterations in blood flow and hydrostatic capillary pressure due to the decrease in arterial inflow pressure ...
Codner M A - - 1995
The purpose of this study was to evaluate the intraoperative changes in physiologic blood pressure following vascular delay of the TRAM flap. Ligation of the superficial and deep inferior epigastric vessels 2 weeks prior to the TRAM flap was performed. The incidence of fat necrosis was 4.3 percent in 23 ...
Meyer-Schwickerath R - - 1995
BACKGROUND: Does the venous collapse phenomenon provide the possibility of venous dynamometry? METHOD: A technical model is presented which allows analysis of the conditions of the collapse of the central retinal vein in vitro. The conditions of the venous collapse were analysed with regard to intraocular pressure, intravasal pressure in ...
Andersen R - - 1995
BACKGROUND: Intestinal ischaemia may be difficult to recognize in the early stages. Increased urinary recovery of water-soluble contrast medium during and intestinal follow-through has been suggested as a sign of bowel ischaemia. METHODS: Urinary excretion of the isosmolar water-soluble X-ray contrast medium iodixanol was measured after instillation via an orogastric ...
Fevang J - - 1995
While changes in blood flow associated with simple intestinal obstruction have been studied extensively, little is known about blood flow changes associated with strangulation obstruction. Closed loop strangulation was produced in anesthetized cats by means of a baby pressure gasket. Intestinal blood flow was measured by transit time flowmetry. Blood ...
Hasbargen J A - - 1995
We performed a prospective, randomized study of various needle gauges and the effect on recirculation, venous pressure, and puncture site bleeding. All patients (n = 21) in our unit consented and participated. We studied 14, 15, 16, and 17 gauge needles, 2.5 cm in length with a "backeye" conformation. Each ...
Odeberg S - - 1995
Venous admixture as a measure of pulmonary gas exchange was studied before and during laparascopic cholecystectomy in 12 patients with normal healthy cardio-pulmonary function. After induction of anaesthesia the patients were studied by radial and pulmonary arterial catheterization and simultaneous arterial and mixed venous blood gas sampling in the horizontal, ...
Shrier I - - 1995
Previous studies have shown that blood flow through skeletal muscle is regulated by changes in an arteriolar vascular waterfall [critical pressure (Pcrit)] and a proximal (arterial) resistance (Ra) element. To determine whether Pcrit still exists during maximal vasodilation, we pump perfused vascularly isolated canine hindlimbs. We set outflow pressure to ...
Christen Y - - 1995
BACKGROUND: The effects of surgical pneumoperitoneum on lower-limb venous hemodynamics have already been studied; however, the effects of intermittent compression boots are not known in such venous-stasis conditions. METHODS: In 12 volunteers and 12 patients, the venous hemodynamic effects of intermittent leg compression were studied under external abdominal pressure or ...
Willemsen J J - - 1995
An HPLC separation method combined with fluorometric detection was extended to enable simultaneous assessment of plasma 3H-labeled and endogenous epinephrine (E) and norepinephrine (NE). Forearm fractional extraction (FFE) of 3H-labeled E and NE and of endogenous E was measured in 40 healthy volunteers who were receiving a continuous infusion of ...
van Kuijk W H - - 1995
BACKGROUND: The present study was performed to assess the role of the extracorporeal blood temperature in the disparate cardiovascular response between isolated ultrafiltration and combined ultrafiltration-haemodialysis. METHODS: In twelve stable dialysis patients (21-77 years), blood pressure and heart rate (Finapres) as well as forearm vascular resistance and venous tone (strain-gauge ...
Morris W P - - 1995
BACKGROUND: Continuous venous air emboli have been detected in the inferior vena cava and smaller veins using transesophageal echocardiography in patients with positive pressure ventilation and associated pulmonary barotrauma. The authors hypothesized that gas entered the venous circulation, following dissection of small vessels at several sites in the subcutaneous or ...
Drieu la Rochelle C - - 1995
1. The role of vasoconstrictor 5-HT1-like receptors in the control of vascular reactivity in vivo has been relatively little studied, particularly with regards to venous function. Using an anaesthetized dog model, we have investigated the haemodynamic profile of the selective 5-HT1-like agonist, sumatriptan, focussing on the reactivity of the saphenous ...
Hanna G B - - 1995
A variable model of venous hypertension was used to examine the immediate effect on skin oxygenation and blood flow. Measurements were carried out using laser Doppler flowmetry, transcutaneous oximetry and both macro- and micro-lightguide spectrophotometry to measure haemoglobin saturation (SO2). Assessments were performed on 20 normal subjects and in ten ...
Pierri A - - 1995
BACKGROUND: The operative treatment of a large abdominal incisional hernia increases intra-abdominal pressure (IAP). This study was done to verify if this IAP elevation acts on the cardiocirculatory function. STUDY DESIGN: Hemodynamic measurements were performed in five patients who underwent massive incisional hernioplasty before and after abdominal wall closure. RESULTS: ...
Yung M - - 1995
OBJECTIVE: To determine whether pressure in the inferior vena cava (IVC) is similar to central venous pressure. METHODOLOGY: Prospective measurement of both central venous pressure (CVP) and inferior vena cava pressure (IVCP) in the same child; each child had to have both catheters in situ. Two measurements of each pressure ...
Virolainen J - - 1995
To investigate the effect of a sustained fall in intrathoracic pressure (Mueller manoeuvre) on blood flow through the right heart and on systemic venous dynamics, 16 patients were studied using thermodilution, cinevenograms and simultaneous pressure recordings with two micromanometric transducers. The reductions in airway pressure (median [range]) during two graded ...
Geroulakos G - - 1995
The venous system plays an important role in the determination of cardiac output and venous return. Venous tone is a property of the venous system which reflects the venous resistance and pressure. An increased venous tone caused by venoconstriction leads to an increased net capillary filtration by increasing the venous ...
Fagrell B - - 1995
Insufficiency of the deep venous system of the leg may cause severe disturbances of the skin microcirculation. The pressure in the deep venous system increases markedly during walking when the venous valves are destroyed. This pressure increase is transmitted out through the ankle perforators into the superficial veins of the ...
Beck J R - - 1995
A simple heparin-bonded circuit to facilitate a femoral vein to femoral artery shunt for the treatment of right-sided circulatory failure is proposed. Desaturated venous blood is shunted to the left-sided circulation to increase systemic blood pressure at the expense of saturation. The circuit comprised 1/4 inch x 3/32 inch tubing ...
Schleifer W - - 1995
Laparoscopic procedures with CO2-pneumoperitoneum are used widely in gynaecology and surgery. The effects of a 15 degrees head-down position, different intra-abdominal pressures (IAP) and CO2-insufflation flows on cardiorespiratory parameters were studied prospectively in 18 gyneacologic patients under general anaesthesia. The 15 degrees head-down position led to significant changes in heart ...
Haworth S T - - 1995
The reported values for the pressure difference between lobar artery and subpleural arteriole and between subpleural venule and lobar vein as a fraction of the total arterial-to-venous pressure drop across the dog lung have varied considerably. We carried out the present study to provide an additional set of measurements and ...
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