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Results 351 - 400 of 1277
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Schaller Carlo - - 2002
Recent experiments showed an upward shift of the lower limit of autoregulation (AR) following photochemical occlusion of cortical veins in the rat. The goal of the present study was to prove the hypothesis that occlusion of cortical veins will be associated with impairment of the upper limit of autoregulation as ...
Fu Qi - - 2002
The present study was performed to test the hypothesis that calf venous capacitance would be reduced by mild gravitational stress through a vasomotor reflex in humans, and this response could be diminished with advancing age. Nine young (31 +/- 1 years, mean +/- SE) and 9 elderly (69 +/- 1 ...
Chieveley-Williams Sarah - - 2002
STUDY OBJECTIVES: To determine whether the change in bladder pressure (Pblad) and central venous pressure (Pcvp) may reflect the changes in esophageal pressure (Pes) and gastric pressure (Pgas) when inspiratory pressure support (IPS) is altered. DESIGN: Prospective clinical study. SETTING: The ICUs of a teaching hospital. PATIENTS: Ten patients currently ...
DeSanctis M T - - 2002
Noninvasive macro- and microcirculatory tests provide quantitative information that offers answers to most questions posed in venous diseases. Duplex scanning is used to assess the macrocirculation, and microcirculatory methods are used to assess and quantify venous microangiopathy. Laser Doppler flowmetry is used to assess perfusion. Transcutaneous Po(2) and Pco(2) measurements ...
Kleinekofort W - - 2002
Prospective monitoring of static venous pressure is an established tool to detect outflow stenoses in a vascular access. However, with this method it is not possible to identify vascular stenoses which are localized between the arterial and venous dialysis needle. We describe a new approach based on both static arterial ...
Brest van Kempen A B - - 2002
Cardiac surgery on Jehovah's Witnesses is a great challenge for the cardiothoracic surgery team and especially for the perfusionist. To reduce the risk of surgery in these patients, a very small extracorporeal circuit was designed to decrease the amount of priming volume and thereby the degree of hemodilution. A small ...
Cesarone M R - - 2001
The involvement of the microvascular structure in chronic venous insufficiency (CVI) causes venous hypertensive microangiopathy (VHM), which leads to venous ulceration. VHM is characterized by enlarged and ramified capillaries, increased flux and capillary permeability, edema, and altered function of microlymphatics. TcPO2 is decreased and CO2 increased. This perfusional paradox is ...
Burrows A M - - 2001
OBJECTIVE: The present study investigates the potential relationship between craniosynostosis and any changes in endocranial vasculature. The hypothesis that crania from rabbits with familial, nonsyndromic coronal suture synostosis and crania from rabbits with experimental immobilization of the coronal suture are associated with altered form of the middle meningeal vessels and ...
Zippel K C - - 2001
Using corrosion casting, we demonstrate and describe a new vascular system--the vertebral venous plexus--in eight snake species representing three families. The plexus consists of a network of spinal veins coursing within and around the vertebral column and was previously documented only in mammals. The spinal veins of snakes originate anteriorly ...
Piechnik S K - - 2001
OBJECTIVE: The cerebrovascular bed and cerebrospinal fluid circulation have been modeled extensively except for the cerebral venous outflow, which is the object of this study. METHODS: A hydraulic experiment was designed for perfusion of a collapsible tube in a pressurized chamber to simulate the venous outflow from the cranial cavity. ...
de Laforcade A M - - 2001
Arterial blood pressure measurement and central venous pressure monitoring are important tools in the management of the critically ill pet. Central venous pressure is reflective of right atrial pressure and provides information concerning volume status. Arterial blood pressure is helpful in determining if perfusion to vital tissues is adequate. By ...
Vieri-Gashi, E. I.
This paper describes the venous pressure effect to blood pressure signals measured by the electronic palpation method. It was shown, that in 52 percent of blood pressure measurements made with inflating cuff the linear increase in venous blood pressure was also increasing palpated signal's amplitude linearly. It was found, that ...
Rowlands T E - - 2001
BACKGROUND: Pro- and anti-inflammatory cytokine release occurs with abdominal aortic aneurysm (AAA) repair although the relative contribution of each is currently poorly understood. Ischaemia-reperfusion injury is thought to play a greater role following open (OR) than endovascular (ER) repair, with resultant greater perioperative morbidity. METHODS: Thirty-two patients undergoing OR (n ...
Cesarone M R - - 2001
Noninvasive tests have been developed to provide qualitative and quantitative information that can offer answers to most questions posed in venous diseases. While duplex scanning is used to assess the macrocirculation, microcirculatory methods assess and quantify venous microangiopathy. Laser Doppler flowmetry is used to assess tissue viability and perfusion. Transcutaneous ...
Zhang Q - - 2001
The effects of limb elevation and increased intramuscular pressure (IMP) on blood flow in the tibialis anterior muscle and leg neuromuscular function were studied in eight healthy subjects. Muscle blood flow (MBF) was measured by photoplethysmography using a custom-designed probe. IMP was elevated bilaterally by vein obstruction (60-65 mmHg) lasting ...
Suzuki T - - 2001
The Safe guide is a central venous puncture needle that serves as both a pilot needle and as an introducer. A guide wire can be inserted into a vein through the side port at the hub of the 22-gauge Safe guides needle initially inserted as a pilot needle. However, guide ...
Sugerman H J - - 2001
This article gives an overview, citing animal and clinical studies, of the effects of increased intra-abdominal pressure (IAP) in severe obesity. Animal studies demonstrate that increased IAP increases pleural pressure, cardiac filling pressures, femoral venous pressure, renal venous pressure, systemic blood pressure, and vascular resistance, renin and aldosterone levels, and ...
Tkachenko B I - - 2001
The dynamics of changes in blood flow and pressure in the superior and inferior vena cava, total venous return, and right atrial pressure in response to pressor stimuli were studied in acute experiments on cats. It was shown that blood flow and pressure in caval veins changed synchronously and unidirectionally, ...
Monahan K D - - 2001
We determined the independent and interactive influences of aging and habitual endurance exercise on calf venous compliance in humans. We tested the hypotheses that calf venous compliance is 1) reduced with age in sedentary and endurance-trained men, and 2) elevated in young and older endurance-trained compared with age-matched sedentary men. ...
Mulhall J P - - 2001
Erectile dysfunction (ED) is an increasingly prevalent medical problem, affecting up to 50% of men aged between 40 and 70-y-old. Many cases are vasculogenic and some of these stem from the inability of the penis to store blood during erection due to leak into the venous system, termed corporo-venocclusive dysfunction ...
Cavani S - - 2001
The role of hemodynamic and regulatory factors in the arterial pressure response to hemodialysis induced hypovolemia was investigated by means of a computer model of the cardiovascular system, including the main short-term pressure regulatory mechanisms. The model mimics the arterial and venous systemic circulation, Starling's law and inotropic heart regulation, ...
Henke P K - - 2001
BACKGROUND: Therapy for deep vein thrombosis (DVT) resolution in those patients in whom a complication or contraindication to anticoagulation occurs is limited. As prior work suggests that thrombus maturation involves early influx of neutrophils (PMN) and neovascularization, we hypothesized that administering the proinflammatory/proangiogenic chemokine interleukin (IL)-8 might accelerate thrombus resolution. ...
Inoue H - - 2001
Nitric oxide (NO) donors including organic nitrates dilate capacitance vessels. As inhibition of phosphodiesterase type 5 results in the accumulation of guanosine 3'5'-cyclic monophosphate (cGMP), specific phosphodiesterase type 5 inhibitors are expected to have a vasodilator property similar to that of NO donors. To test this hypothesis, we examined the ...
Rivers E P - - 2001
In the initial treatment of a critically ill patient, blood pressure, heart rate, urine output, and central venous pressure guide resuscitative efforts. Despite normalization of these variables, global tissue hypoxia may still persist and has been implicated in the development of multiorgan failure and increased mortality. Definitive management includes intensive ...
Wysoki M G - - 2001
This study is designed to evaluate the various physiologic maneuvers (Valsalva, humming, breath-hold) for the potential prevention of air embolism during central venous catheter placement. Central venous pressure measurements were prospectively obtained in 40 patients undergoing central venous catheter placement. The average central venous pressure at baseline was 3.275 mm ...
Westlake W H - - 2001
Retinal venous pressure was examined in six pigs using a balanced servo-nulling micropuncture technique. The mean transmural venous pressure was 0.95 mmHg (SD 1.50 mmHg). The transmural venous pressure was lower at the optic disc than away from the disc (0.32 +/- 1.46 mmHg vs 1.69 +/- 1.19 mmHg, P ...
van Donkelaar C C - - 2001
The vascular waterfall theory attributes decreased muscle perfusion during contraction to increased intramuscular pressure (P(IM)) and concomitant increase in venous resistance. Although P(IM) is distributed during contractions, this theory does not account for heterogeneity. This study hypothesises that pressure heterogeneity could affect the interaction between P(IM) rise and perfusion. Regional ...
Pang C C - - 2001
The venous system contains approximately 70% of the blood volume. The sympathetic nervous system is by far the most important vasopressor system in the control of venous capacitance. The baroreflex system responds to acute hypotension by concurrently increasing sympathetic tone to resistance, as well as capacitance vessels, to increase blood ...
Tkachenko B I - - 2001
The dynamics and amplitude of changes in venous return and right atrial pressure (central venous pressure) in response to pressor stimuli were studied in acute experiments on cats. The increase in venous return was accompanied by either increase, or decrease in the central venous pressure. Thus, shifts in systemic venous ...
Schadt J C - - 2001
The interaction of sensory stressors with the cardiovascular response to blood loss has not been studied. The cardiovascular response to a stressor (i.e., the defense reaction) includes increased skeletal muscle blood flow and perhaps a reduction in arterial baroreflex function. Arterial pressure maintenance during blood loss requires baroreflex-mediated skeletal muscle ...
Sugimachi M - - 2001
We have shown in our previous study that the transfer function between central aortic pressure and tonometric radial arterial pressure can be modeled as a pure elastic lossless tube terminated with a modified Windkessel. We hypothesized, using the model-derived radial arterial flow, that central pressure could be reconstructed by adding ...
Watenpaugh D E - - 2001
Chronic microgravity may modify adaptations of the leg circulation to gravitational pressures. We measured resting calf compliance and blood flow with venous occlusion plethysmography, and arterial blood pressure with sphygmomanometry, in seven subjects before, during, and after spaceflight. Calf vascular resistance equaled mean arterial pressure divided by calf flow. Compliance ...
Nightingale A K - - 2001
OBJECTIVES: The goal of this study was to assess whether endothelial dysfunction occurs in the forearm venous capacitance bed of patients with chronic heart failure (CHF) and to determine the role of nitric oxide (NO) in modulating venous tone. BACKGROUND: Control of venous tone is crucially important in CHF. More ...
Buchhorn R - - 2001
BACKGROUND: The hemodynamic status after a Fontan type procedure for definitive palliation of functionally univentricular hearts is dominated by a high central venous pressure, which seems to be one of several factors responsible for venous congestion appearing as a frequent complication in the early and late postoperative course. The purpose ...
Cordts P R - - 2001
Upregulation of adhesion molecules and neutrophil infiltration of venous valve cusps may be risk factors for chronic venous insufficiency. But studies that focus on the target organ (vein) fail to consider the influence of systemic inflammation on WBC behavior in the microcirculation. This study probes the gut-liver axis as a ...
Varbiro S - - 2001
OBJECTIVE: The venous system may play a role in the development and progression of postmenopausal hypertension. In the present study, we investigated the effect of chronic angiotensin II-induced hypertension on the geometric, elastic, and contractile properties of the saphenous vein in sex hormone deficient and replaced female rats. METHODS: Thirty ...
van Gemert M J - - 2001
Our objective was to appraise whether an increased amniotic fluid pressure by polyhydramnios can beneficially affect monochorionic twins that are haemodynamically connected by arterio-venous plus arterio-arterial placental anastomoses. We assessed the effects of polyhydramnios in monochorionic twin placentas, combining (a) data from previous in vitro placental perfusion experiments in singleton ...
Ting C K CK Department of Anesthesiology, Veterans General Hospital-Taipei and School of Medicine, National Yang-Ming University, 201, Sec. 2, Shi-Pai Rd., Pei-Tou 112, Taipei, Taiwan, - - 2001
Venous air embolism (VAE) is not uncommon during craniotomy, but repeated attacks of VAE during a single surgical procedure is rarely seen. We report a successful intraoperative management of repeated attacks of air embolism in a patient who sustained craniotomy for intracranial hemorrhage (ICH) in prone position. A 70-year-old male ...
Loubser P G - - 2001
OBJECTIVE: To determine whether internal jugular venous valves influence inflow pressure during retrograde cerebral perfusion. DESIGN: Prospective study. SETTING: Community hospital, university setting, single institution. PARTICIPANTS: Ten patients undergoing reconstructive aortic arch surgery with profound hypothermic circulatory arrest. INTERVENTIONS: During retrograde cerebral perfusion, inflow pressure was continuously measured at 2 ...
Kunimoto B - - 2001
Chronic venous insufficiency is the most common cause of leg ulcers. Its incidence increases as the population ages. Managing venous leg ulcers involves treating the cause, optimizing local wound care, and addressing patient-centered concerns. The cornerstone of the diagnosis of chronic venous insufficiency includes demonstrating venous disease. The clinician must ...
Cavalcanti S - - 2001
Several late complications jeopardize the clinical performance of recipients of the Fontan operation. The underlying causes have been referred to disturbed flow dynamics in the cavopulmonary connections. Presumably, the large pressure drops occurring in the inferior and superior connections play a pivotal role in the pressure level of the entire ...
Hung M Y - - 2001
We report on a case of pulsatile femoral veins with a systolic thrill and murmur in a 26-year-old patient who exhibited severe tricuspid regurgitation. The pulsatile nature of the veins may result from the 'ventricularization' of venous pressure with each pressure pulse. The observed systolic thrill and murmur may be ...
Perry M D - - 2001
FCS is a recognized clinical entity that has few consistent clinical signs except tense swelling. A high degree of clinical suspicion is necessary to provide appropriate treatment. Invasive direct pressure monitoring is needed to diagnose FCS. High-energy injuries are known to cause FCS, but individual risk factors, such as prolonged ...
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 ...
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