In order to study the effects of chronic venous hypertension due to heart failure on blood fibrinolytic activity, tissue plasminogen activator (t-PA) antigen, plasminogen activator inhibitor 1 (PAI-1) antigen, t-PA activity and PAI activity were measured before and after venous occlusion of the arm for 20 min in 15 patients ...

The appearance of pulmonary venous sphincters was studied in normotensive and spontaneously hypertensive rats using scanning electron microscopy of microvascular corrosion casts and transmission electron microscopy of tissue sections. Vascular casts were prepared either after lavage with Tyrode solution or after glutaraldehyde prefixation. Pronounced pulmonary venous sphincters were more frequently ...

Recently, we presented a compartmental model of the pulmonary vascular resistance (R) and compliance (C) distribution with the configuration C1R1C2R2C3 (J. Appl. Physiol. 70: 2126-2136, 1991). This model was used to interpret the pressure vs. time data obtained after the sudden occlusion of the arterial inflow (AO), venous outflow (VO), ...

Extracorporeal membrane oxygenation (ECMO) is lifesaving for infants with severe respiratory distress but is complicated by severe intracranial hemorrhage in 10% to 30% of patients. Intracranial venous hypertension, as a result of ligation of the internal jugular vein (IJV), has been hypothesized as a contributing factor to cerebral edema and ...

STUDY OBJECTIVE: The purpose of this study was to observe, measure, and describe the changes in central venous oxygen saturation during CPR and immediately after return of spontaneous circulation. It also was to examine the clinical utility of continuous central venous oxygen saturation monitoring as a indicator of return of ...

A reduced venous compliance (VC) and inadequate venoconstriction may impair hemodynamics during hemodialysis, the first by impairing plasma volume preservation and by inducing a steep fall in central venous pressure (CVP) during minor plasma volume loss, the second by inadequate mobilization of hemodynamically inactive blood volume. For the protocol A, ...

An experimental model used with the intention of mimicking the ischaemic condition in patients with arterial obliterative disease was evaluated. The influence of reduced effective perfusion pressure by increased external pressure on leg blood flow and metabolism was determined during exercise in 10 healthy subjects. Catheters were inserted into the ...

BACKGROUND: Tolerance to the effects of organic nitrates develops rapidly during continuous exposure to these drugs; its main mechanism seems to be an intracellular sulfhydryl group depletion. However, the relative susceptibility to the development of nitroglycerin tolerance of the arterial or venous circulation in humans is still a matter of ...

Fluid resuscitation and transfusion therapy are particularly critical in patients undergoing extensive vascular operations because of diffuse atherosclerosis and the risk of perioperative myocardial infarction. Sophisticated perioperative monitoring has reduced the mortality rate substantially, but indications for transfusion remain controversial. We determined erythrocyte volume, (EV), total blood volume (TBV) and ...

Air plethysmography (APG) was used to measure maximal venous outflow rate (MVO), a test for proximal venous obstruction; venous volume; venous filling index, an estimate of valvular incompetence; ejection fraction (EF), a test of calf-muscle pump efficiency; and residual volume fraction (RVF), an estimate of ambulatory venous pressure. MVO was ...

A 24-year-old married woman had an angiokeratoma of the vulva measuring 3 x 3 x 4 mm localized at the clitoris. The nodule was noticed when she was pregnant with her first child. This tumor grew with occasional tenderness and bleeding during pregnancy, but its size did not change after ...

The modified Fontan operation has gained wide acceptance as a functional corrective procedure for patients with CHD with single ventricle physiology. Long-term survival and palliation of symptoms are excellent with most patients able to lead normal lives. The absence of a pulmonary contractile ventricle means that the single ventricle is ...

Experiments during spaceflight and its groundbase analog, bedrest, provide consistent data which demonstrate that numerous changes in cardiovascular function occur as part of the physiological adaptation process to the microgravity environment. These include elevated heart rate and venous compliance, lowered blood volume, central venous pressure and stroke volume, and attenuated ...

Venous pressure measured by the dialyzer is an unreliable measure of intra-access venous pressure. During dialysis and zero extracorporeal blood flow, intra-access venous limb pressure (VPd) was measured directly 401 times in 133 subjects using a high flow "in-line" three-way stopcock adjacent to the venous return needle. Subjects with systolic ...

This is a condensed consensus report, summarizing the present status of various aspects of epidemiology, diagnosis, and treatment of venous ulcers. There are conflicting results regarding the prevalence of venous ulcers ranging from 0.18 to 1.3%, depending on the types of ulcers reported. With regard to macrovascular changes preceding venous ...

To study the mechanism whereby positive end-expiratory pressure (PEEP) decreases venous return, we used a closed-chest canine venous bypass preparation to study the effects of 10 mm Hg PEEP on the systemic venous pressure-flow curves from the superior and inferior vena cava (SVC and IVC). These curves were characterized by ...

The main objective of these experiments was to develop and characterize a new experimental model of venous thrombosis, and determine whether a combination of vascular wall damage (crushing with hemostat clamps) and prolonged stasis produced more reproducible clots than prolonged stasis per se. Rabbits were laparotomized, and a segment of ...

Glyceryl trinitrate (GTN) is known to be a potent venodilator, but the effects might differ depending on the regime of administration. Using a radionuclide blood pool method we examined the changes in peripheral (and pulmonary) venous volume induced by GTN administered in three ways: short (4 min) intravenous infusions at ...

In patients with venous hypertension due to postphlebitic syndrome or varicose veins skin changes, liposclerosis and ulcerations are associated with increased skin blood flux at rest, a decreased venoarteriolar response and increased capillary filtration. Using laser-Doppler flowmetry we studied skin flux and the venoarteriolar response in the perimalleolar region in ...

This study investigates whether walking or running prevents the formation of edema in the lower leg. In 18 volunteers changes in calf volume were measured using strain gauge plethysmography during slow (3 km/h) and fast (6 km/h) walking or running (10 km/h) on a treadmill for 20 min each. Venous ...

Compression stockings and bandages have been shown to improve venous haemodynamics and may act by reducing venous reflux. The aim of this study was to assess the mechanism of action of compression therapy on venous function and to determine whether such treatment may correct valvular incompetence. Both lower limbs of ...

The performance of a new double lumen central venous haemodialysis catheter was tested in two laboratory models. In a bench model the patient's venous system was simulated by a reservoir from which water or glycerol was drawn through a fixed tube. A double lumen silastic catheter was then inserted into ...

Recent research into the relationship between retinal venous occlusion and general vascular disorders has shown that retinal venous occlusion seems to be related only to systemic hypertension. The role of systemic hemorrheologic parameters in the pathophysiology of venous occlusion is a controversial one. Of the various treatment modalities, isovolemic hemodilution ...

OBJECTIVE: To test the hypothesis of reduced venous compliance and increased cardiovascular responses to volume expansion and alpha-agonist stimulation. METHOD: Non-hypertensive healthy young men with positive (PFH) and negative family histories of hypertension were investigated regarding peripheral haemodynamics and changes in central venous pressure (CVP) and arterial blood pressure in ...

The venous system is supremely important in the control of cardiac output. Drugs which affect the venous system have profound effects on haemodynamics. This review comments on the methods available for the determination of venous compliance, resistance, and unstressed volume and describes the mean circulatory filling pressure (MCFP) technique, its ...

The objective of this discussion has been to describe a simple conceptual model of the circulation that emphasizes the role of the venous capacitance vasculature and is based on simplified vascular pressure-volume relationships. First, it is hoped that this approach will avoid some of the misunderstandings and contradictions that have ...

We have designed and constructed a ruler ("Torrstick") calibrated in millimeters of mercury for the measurement of hydrostatic pressure differences. Marks are placed on a measuring stick every 1.34 cm, to afford the best compromise between a column of 0.9% saline solution and a column of blood. Several uses for ...

To clarify the effect of intermittent positive-pressure ventilation (IPPV) on systemic circulation, mean systemic filling pressure (Psf) and circulating blood volume were measured together with other hemodynamic parameters of capacitance vessel. Change in circulating blood volume was determined by dilution with 51Cr-labeled erythrocytes. Vascular compliance (Cvas) was measured from the ...

In a placebo-controlled trial, we have studied the vasodilator properties of bolus doses of nitroglycerin (TNG) and isosorbide dinitrate (ISDN) in 32 patients during cardiopulmonary bypass with a constant pump flow. Blood volume of the venous reservoir and mean arterial pressure were recorded for 10 min after drug administration to ...

The effects of selective cardiopulmonary receptor unloading on atrioventricular (AV) conduction were examined in 7 patients undergoing electrophysiologic testing. During -35 mmHg lower body negative pressure (LBNP) before autonomic blockade with propranolol and atropine, the AV-nodal conduction time (AH interval), the effective and functional refractory periods of AV node decreased ...

Central venous pressure measurements in the abdominal inferior vena cava were compared with measurements in the right atrium in 10 infants and 10 children during cardiac catheterization. At end expiration, the mean pressures at these two sites were within 1 mm Hg of each other in all 20 patients, with ...

We tested the hypothesis that the frequency and amplitude of spontaneous venular contractions in the bat wing could be modulated by changes in transmural pressure. In one series of experiments, venous pressure in the wing was elevated by pressurizing a box containing the body of the animal while the wing ...

To test whether quinaprilat, a new angiotensin-converting enzyme (ACE) inhibitor, has any venous effect, we measured its immediate effects on mean circulatory filling pressure (MCFP), intravascular volume, and total body vascular (i.e., venous) compliance in conscious rats with healed myocardial infarction induced by coronary artery ligation. MCFP was determined by ...

The cardiovascular and haematological effects of purified prothrombin activator derived from the venom of the Australian Common Brown Snake (Pseudonaja textilis) were studied in anaesthetised, mechanically ventilated dogs. Severe depression of systemic blood pressure and cardiac output and a rise in central venous pressure were observed. Thrombocytopenia, prolongation of both ...

The administration of regional anesthesia to women with moderately severe and severe pre-eclampsia is commonly preceded by intravenous hydration guided by central venous pressure (CVP) monitoring. We are reporting the case of a gravida with incipient HELLP syndrome whose fluid management before, during, and after cesarean section under continuous extradural ...

STUDY OBJECTIVE: To test the hypotheses that in multiple pathophysiologic settings (1) end-expiratory central venous pressure measurements in the intraabdominal inferior vena cava accurately reflect those in the superior vena cava and (2) mean central venous pressure monitoring is as reliable in the inferior vena cava as it is in ...

We have used the mercury in silastic strain gauge plethysmography (MSG) system, which is wholly non-invasive, to obtain values (mean +/- s.e.m.) for the following parameters in the legs of supine control subjects: venous pressure (Pv) 9.89 +/- 0.88 mmHg, vascular compliance (Comp) 3.50 +/- 0.29 ml 100 g-1 mmHg-1 ...

In 48 patients undergoing transsphenoidal surgery for pituitary adenoma, the intrasellar pressure was recorded during surgery. In 14 patients, adenoma blood flow was measured with the technique of local injection of 133xenon. Median intrasellar pressure was 30 mmHg (range 8-62), n = 48, and median adenoma blood flow was 8 ...

An internal jugular catheter, which was inserted into a patient with a traumatic haemopneumothorax, accidentally entered the pleural cavity. This was initially undetected because the two signs most frequently used to confirm correct placement, those of blood reflux and fluctuation of central venous pressure with respiration, were positive. A number ...

To investigate the effect of milrinone (MIL) on systemic capacitance vessels, we measured the mean circulatory filling pressure (MCP) in anesthetized open chest dogs. We measured hemodynamic parameters (a) at baseline blood volume (BV), (b) immediately after bloodletting (5 ml/kg), and (c) immediately after dextran injection (5 ml/kg). These measurements ...

In dogs, the venous blood from the prostate gland was observed under X-ray fluoroscopy to drain into the vertebral venous system under conditions of abdominal compression, the addition of various intraabdominal pressures, and occlusion of the inferior vena cava by a balloon catheter. Pressure in the inferior vena cava and ...

1. The relationship between [K+] in venous effluent blood and alterations in mean arterial blood pressure was studied during static handgrip contractions at 15 and 30% of maximal voluntary contraction (MVC). 2. To further elucidate the importance of K+ in the reflex regulation of blood pressure a situation with normal ...

The long term effect of elastic compression, with an emphasis on the changes in venous wall elasticity, was studied in 10 limbs with varicose veins. By simultaneously measuring venous volume, using the air plethysmograph (APG), and venous pressure, while the venous outflow was occluded, the pressure/volume (P/V) relationship of the ...

Continuous monitoring of mixed venous (SvO2) and central venous (ScO2) oxygen saturation was compared in 7 critically-ill patients (Apache II score: 19 +/- 2.1) to determine whether or not information derived from ScO2 were reliable in clinical practice. Patients were catheterized with both a pulmonary artery (PA) and a central ...

The efficacy of insulin administration in reversing haemodynamic changes in pulmonary oedema in victims of poisonous scorpion sting is assessed by a study based on animal experiments in which insulin administration reversed metabolic and electrocardiographic changes induced by scorpion envenomation. Six previously healthy children aged 18 months to 11 years ...

Pericardial tamponade from an indwelling central venous catheter developed in four orthopaedic patients. Two of these patients died acutely, and the other two sustained severe anoxic brain injury. The early signs of tamponade include tachycardia, hypotension, and increased central venous pressure. The outcome most often is fatal. When a central ...

The cardiohemodynamic effect of (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409), a novel potent vasodilator, was studied in anesthetized open-chest dogs. FK409 (1 to 10 micrograms/kg, i.v.) decreased mean blood pressure, cardiac output and venous return (sum of the flow through the inferior and the superior vena cava). These changes accompanied decreases in left ventricular ...

The venodilatory response to nitroglycerin (0.8 mg sublingually) was measured in 10 healthy young male volunteers in a cool [24.3 +/- 0.6 degrees C skin temperature (Tsk)] and a warm environment (34.7 +/- 0.2 degrees C Tsk). Nitroglycerin caused mean arterial pressure to fall and heart rate to rise in ...

In a prospective study, the results of venous function tests in 19 lower extremities with deep venous insufficiency and in seven control extremities were compared. First, the routine method of asking the patients to exercise their calves was used. Second, cuffs around the calves were rapidly inflated, producing standardized external ...

STUDY OBJECTIVES: To clarify apparently conflicting reports on the hemodynamic effects of the pneumatic antishock garment (PASG). DESIGN: Ten anesthetized dogs with hemorrhagic hypotension had hemodynamics measured without PASG inflation (group 1) and were compared with ten dogs with PASG inflation (group 2). MEASUREMENTS AND MAIN RESULTS: Baseline and immediate ...