Search Results
Results 501 - 550 of 1693
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Raso J - - 1999
The influence of several factors (amplitude of ultrasonic waves, external static pressure, temperature and viscosity of medium) acting, either individually or in combination, on the amount of power transferred to a liquid medium during ultrasonication (power output) was measured by calorimetry. At constant amplitude (150 microns) and pressure (200 kPa), ...
Putzke J D - - 1998
BACKGROUND: Cognitive deficits among heart transplant candidates have been well documented. This study was designed to examine the hypothesis that impaired cognitive test performance among heart transplant candidates may be attributed, in part, to decreased cerebral perfusion secondary to poor cardiac function. METHODS AND RESULTS: Sixty-two patients participated in the ...
Pypendop B H - - 1998
To characterize the hemodynamic effects of medetomidine administered intravenously at doses ranging from 1 to 20 microg/kg, and to determine whether these effects are dose dependent. Prospective randomized multidose trial. Twenty-five clinically normal male beagles (5 groups of 5), aged 1 to 4 years and weighing 13.5 +/- 1.7 kg. ...
Kiely J L - - 1998
BACKGROUND: Some previous reports have indicated beneficial cardiac effects of nasal continuous positive airway pressure (NCPAP) in patients with severe congestive heart failure (CHF), but others have reported deleterious cardiac effects, particularly among patients in atrial fibrillation (AF). The aim of this study was to determine if differences in cardiac ...
Tanaka H - - 1998
Stiffening of central arteries is believed to contribute to the increase in the incidence of cardiovascular disease with age, presumably through its adverse influence on arterial blood pressure. We found that (1) the physiologic link between age-related increases in arterial stiffness and blood pressure appears to be elevated systemic vascular ...
Martino M N - - 1998
In high-pressure-assisted freezing, samples are cooled under pressure (200 MPa) to - 20 °C without ice formation then pressure is released (0.1 MPa) and the high super-cooling reached (approx. 20 °C), promotes uniform and rapid ice nucleation. The size and location of ice crystals in large meat pieces (Longissimus dorsi ...
Brahimi M - - 1998
1. Coronary ischaemic disease and congestive heart failure are the principal causes of mortality in patients with peripheral vascular disease. Whether cardiac hypertrophy is present and even more pronounced in peripheral vascular disease than in other populations has never been explored.2.Twenty-five hypertensive patients were investigated, 11 without and 14 with ...
White R J - - 1998
Early in spaceflight, an apparently paradoxical condition occurs in which, despite an externally visible headward fluid shift, measured central venous pressure is lower but stroke volume and cardiac output are higher, and heart rate is unchanged from reference measurements made before flight. This paper presents a set of studies in ...
Young L E - - 1998
OBJECTIVE: To evaluate temporal hemodynamic effects of dobutamine in horses anesthetized with halothane. ANIMALS: 8 adult Thoroughbreds. PROCEDURE: Anesthesia was induced by i.v. administration of romifidine and ketamine and maintained using halothane in oxygen. After 60 minutes, dobutamine was administered i.v. for 60 minutes at 4 micrograms/kg of body weight/min. ...
Cooper S J - - 1998
A 1-m-long RF-pumped HCN waveguide laser is described. Output power optimizations were performed with mixtures of methane, nitrogen, and helium in the ratios 1:2:0, 1:1:0, 2:1:0, and 8:3:36. The variation of output power as a function of gas pressure, flow rate, waveguide wall temperature, and RF driving power was studied. ...
Bolte A C - - 1998
OBJECTIVE: To compare the haemodynamic efficacy of ketanserin (a selective serotonin2-receptor blocker) with dihydralazine in the management of severe early-onset hypertension in pregnancy. DESIGN: Subgroup analysis within a randomised prospective multicentre trial to compare haemodynamic effects as measured by pulmonary artery catherization. SETTING: Departments of Obstetrics and Gynaecology and Intensive ...
Evans W - - 1998
Acute administration of 17beta-estradiol (E2beta) leads to increases in cardiac output, oxygen delivery, and oxygen consumption and increases the critical cardiac output in the nonpregnant sheep. We sought to determine whether the lack of a critical cardiac output or flow-dependent oxygen consumption during states of low cardiac output in late ...
Tarasiuk A - - 1998
In dogs, scorpion venom causes an immediate increase in cardiac output that declines below baseline values within one hour. We tested the hypotheses that antivenom given before venom injection may prevent changes in cardiac output, while antivenom given after the inotropic stage of envenomation cannot reverse cardiac output decline. Twenty-five ...
Spiering W - - 1998
OBJECTIVE: To assess the degree of agreement between impedance cardiography, using the NCCOM3-R7 device, and the gold standard--the dye dilution method--both under basal conditions and after stimulation of cardiac output. PATIENTS: 35 paired measurements in five healthy male volunteers. INTERVENTIONS: To obtain higher levels of cardiac output, cardiac performance was ...
Yatsu T - - 1998
1. The effects of YM435, a dopamine DA1 receptor agonist, were evaluated in a canine model of acute congestive heart failure. 2. The model was induced in open-chest anesthetized dogs by left anterior descending coronary artery ligation, volume loading, and intravenous infusion of angiotensin II. This resulted in a moderate ...
Weber K - - 1998
Resting hemodynamics were measured before, at 2 and 24 h after the first dose, and after 4 weeks of monotherapy with either metoprolol or carvedilol in a randomized single-blind study. We analyzed results from 24 hypertensive patients (30-68 years of age) with adequate blood-pressure lowering on monotherapy. Acutely, both drugs ...
Kirby R F - - 1998
It has recently been demonstrated in week-old rats that extreme cold challenges that lead to significant bodily cooling result in decreased cardiac rate. To determine whether pups are able to maintain arterial pressure in the face of decreasing cardiac rate in extreme cold, we measured blood pressure in unanesthetized week-old ...
Nekooeian A A - - 1998
1. The effects of CGS 21680, a selective A2A adenosine receptor agonist, on cardiac output, blood pressure, mean circulatory filling pressure (Pmcf), arterial and venous resistances, heart rate and left ventricular end-diastolic pressure were assessed in rats with acute heart failure by means of coronary artery occlusion. 2. Animals (n=6 ...
Cohen R I - - 1998
OBJECTIVE: To determine whether the decrease in cardiac output after nitric oxide synthase inhibition in endotoxemia is due to increased left ventricular afterload or right ventricular afterload. DESIGN: Prospective, randomized, unblinded study. SETTING: Research laboratory at an academic, university medical center. SUBJECTS: Nonanesthetized, sedated, mechanically ventilated pigs. INTERVENTIONS: Pigs were ...
Stoll M - - 1998
In stroke penumbra perfusion depends passively on hemodynamics. So far hemodynamic effects of low molecular weight hydroxyethylstarch (HES) has not been investigated. Ten stroke patients received hypervolemic HES therapy. Cardiac output and heart rate were monitored using the bioimpedance method, blood pressure by conventional measurement. The Scandinavian Stroke Scale assessed ...
Mirkovic T - - 1998
The goal of this experiment was to determine whether the type of tight supply-and-demand relationship between cardiac output and metabolic demand for O2 seen in juvenile and adult fish applies during larval development. To this end, we looked at how the heart rate, stroke volume, and cardiac output of rainbow ...
Abe Y - - 1998
To obtain a physiological response by a total artificial heart (TAH), while eliminating the hemodynamic abnormalities commonly observed with its use, we proposed the use of a conductance- and arterial pressure-based method (1/R control) to determine TAH cardiac output. In this study, we endeavored to make use of a variable ...
Sugi K - - 1998
We observed cardiac prolapse following right pneumonectomy in which the patient experienced a 90 degree rotation of the heart and compression of right ventricular outflow tract from behind by the aorta, which led to an increase in right atrial pressure and a decrease of pulmonary artery pressure and cardiac output. ...
Talwar A - - 1998
Haemodynamic responses to hypothermia were studied at normal haematocrit and following the induction of acute normovolaemic haemodilution. Experiments were performed on 20 cats anaesthetized with a mixture of chloralose and urethane in two groups. In one group (n = 10) the effects of hypothermia on various haemodynamic variables were studied ...
Létienne R - - 1998
1. Simultaneous measurements of arterial pressure and cardiac output (n = 8), mesenteric blood flow (n = 7) or hindquarters (n = 8) blood flow were performed during 1 h periods in conscious rats, before and after acute pharmacological blockade of the autonomic, renin-angiotensin and vasopressin systems. In the latter ...
Rosenberg G - - 1998
In vivo characterization studies were performed to compare the dynamic in vivo performance of the Penn State/3M Health Care electric total artificial heart to existing in vitro data. Fully implanted systems were utilized including the artificial heart, controller, backup batteries, compliance chamber, and transcutaneous energy transmission. Catheters were implanted to ...
Yang R - - 1998
Vascular endothelial growth factor (VEGF) produces beneficial angiogenesis in animal models of coronary and peripheral ischemia. However, intravenous bolus injection of Chinese hamster ovary cell (CHO)-derived VEGF produces adverse effects on hemodynamics. The present study examined pharmacokinetic and hemodynamic responses to Escherichia coli-derived VEGF, which will be used in clinical ...
Zheng Q - - 1998
In order to explore the mechanism of hemodynamic changes caused by high biliary tract pressure, we established an animal model of high biliary tract pressure, in which the disturbance of hemodynamics developed. The cervical or abdominal vague nerve was then blocked. It was observed that when the biliary tract pressure ...
Angus D C - - 1997
BACKGROUND: Previous studies have shown "beat-to-beat" variation in systemic BP with high-frequency jet ventilation (HFJV). However, it is not clear if such changes are paralleled by changes in cardiac output. OBJECTIVE: To characterize the effect of HFJV near or equal to the heart rate (HR) on beat-to-beat cardiac output in ...
Hirschl M M - - 1997
OBJECTIVE: To assess whether the measurement of cardiac output by computer-assisted analysis of the finger blood pressure waveform can substitute for the thermodilution method in critically ill patients. DESIGN: Prospective data collection. SETTING: Emergency department in a 2000-bed inner city hospital PATIENTS: Forty-six critically ill patients requiring invasive monitoring for ...
Rydberg A - - 1997
The aim is to develop a computer model representative of the circulation in a patient with a uni-ventricular heart surgically palliated by a total cavo-pulmonary connection (TCPC). The effects of known hazardous exposures on this type of circulation are investigated. A model of the cardiovascular system is built using standard ...
Grönlund J - - 1997
Transcephalic electrical impedance offers a technique for non-invasive, cot-side monitoring of neonatal cerebral circulation but the exact nature of the signal is somewhat ambiguous. The impedance signal is examined in an animal project where the ventilator settings are adjusted (20 min-1-10 min-1-40 min-1 for 10 min periods each) to produce ...
Horban A - - 1997
In isolated perfused working rat hearts we have studied the effects of norepinephrine (NE) and of pressure as well as volume overload alone, and in combination on heart function and expression of the proto-oncogenes c-fos and c-myc. This preparation was functionally stable over the observation period of 120 min. NE ...
Tournadre J P - - 1997
We have investigated the influence of a cold water bolus (CWB) injection on overestimation of cardiac output (CO) in low CO states in anaesthetized dogs. CO was measured using three methods: (1) thermodilution (TD), (2) electromagnetic (EM) flow meter placed on the pulmonary artery and (3) transoesophageal echo-Doppler (OD) placed ...
Tarasiuk A - - 1997
Scorpion venom can induce in dogs severe haemodynamic changes leading to rapid rise in systemic blood pressure and cardiac output, followed by reduction of cardiac output and blood pressure within 1 h. The decrease in cardiac output is not related to myocardial dysfunction (Tarasiuk et al. 1994). We hypothesized that ...
Serikov V B - - 1997
In 25 sheep and 5 goats, which were anesthetized, intubated and mechanically ventilated a sudden decrease in the inspired gas humidity was used to cool the lungs. The dynamics of the temperature of expired gas and its relationship to ventilation rate and cardiac output measured by thermodilution were investigated. In ...
Marik P E - - 1997
OBJECTIVE: To determine the limits of agreement between the cardiac output and volumetric data estimated by impedance cardiography with the cardiac output determined by thermodilution and the left ventricular ejection fraction and end-diastolic volume estimated from left ventriculography. DESIGN: A prospective study. SETTING: The cardiac catheterization laboratory of a university-affiliated ...
Simma B - - 1997
OBJECTIVE: To assess whether the change in cardiac output after volume replacement is due to elevation of stroke volume or heart rate and to determine the effect of mechanical ventilation on the hemodynamic situation. DESIGN: Prospective study. SETTING: A ten-bed neonatal intensive care unit (level III) at a university hospital. ...
Yang R - - 1997
Scatter factor (SF), also known as hepatocyte growth factor, is a potent mitogen that has been suggested to exhibit greater efficacy than vascular endothelial growth factor (VEGF) in rabbits with hindlimb ischemia. Our study examined the effects of SF on cardiovascular hemodynamics and compared the responses to VEGF. Hemodynamic parameters ...
Shibata R - - 1997
Norepinephrine (NE) is one of the most potent positive inotropic drugs available for the treatment of low-output state following open-heart surgery. However, its inotropic effect is often masked by a significant increase of peripheral vascular resistance due to marked vasoconstriction. The purpose of the present study was to investigate whether ...
Steimle A E - - 1997
BACKGROUND: During therapy to relieve congestion in advanced heart failure, cardiac filling pressures can frequently be reduced to near-normal levels with improved cardiac output. It is not known whether the early hemodynamic improvement and drug response can be maintained long term. METHODS AND RESULTS: After referral for cardiac transplantation with ...
Sbarouni E - - 1997
The hemodynamic effects of estrogens in replacement doses have not been fully clarified; therefore, we studied the acute hemodynamic changes after 0.625 and 1.25 mg of conjugated estrogens, administered intravenously, using a thermodilution catheter, in postmenopausal women without structural heart disease. Pulmonary and systemic pressures and resistances and stroke volume ...
Dumont L - - 1997
BACKGROUND: In nonobese patients, peritoneal insufflation has consistently been shown to influence parameters of preload and afterload as well as cardiac output. Obese patients have an abnormal and particular cardiovascular status. The aim of this study was to investigate the hemodynamic changes induced by an increase of intra-abdominal pressure in ...
Jacobsohn E - - 1997
PURPOSE: To review the physiology of cardiac output regulation by the peripheral vasculature. This will enable the clinician to understand and manage the complex circulatory changes in various forms of shock, and in other common altered circulatory states encountered in anaesthetic practice. SOURCE: Articles were obtained from a Medline review ...
Brandi L S - - 1997
OBJECTIVE: To calculate cardiac ouptut from dual oximetry with carbon dioxide production (VCO2) and oxygen consumption (VO2) measured by a new metabolic monitor, and to compare these values with measurements made simultaneously using the thermodilution method during the steady state condition. DESIGN: Prospective, comparative clinical study. SETTING: The adult postsurgical ...
Hahn R G - - 1997
The purpose of this experimental study was to find out whether central haemodynamic activity influences the precision of the ethanol method used to monitor fluid absorption during endoscopic surgery. Today, the nomograms used together with this monitoring method indicate that increasing breath ethanol values reflect progressively larger absorption volumes regardless ...
Estagnasié P - - 1997
OBJECTIVE: The determination of basal cardiac output (CO) and of its variations during different therapeutic interventions liable to increase or decrease it in mechanically ventilated patients using transesophageal echocardiography (TEE). DESIGN: To compare CO measurements simultaneously obtained by transmitral single-plane TEE and thermodilution. SETTING: Medical intensive care unit. PATIENTS: Twenty-two ...
Uchikoshi F - - 1997
We examined the use of an abdominal wall retraction method instead of pneumoperitoneum in laparoscopic cholecystectomy for patients with cardiac disease to prevent the hemodynamic deterioration associated with pneumoperitoneum. Eight patients with cardiac diseases, mainly valvular or coronary artery diseases, underwent laparoscopic cholecystectomy under hemodynamic monitoring. Five patients without cardiac ...
Lazor M A - - 1997
OBJECTIVES: This study was conducted to compare continuous cardiac output (CCO) with bolus thermodilution cardiac output (BTD) at steady state, and to compare the response time of STAT CCO with that of trend CCO, mean arterial pressure, and mixed venous oxygen saturation [SvO2] during an acute hemodynamic change. DESIGN: Prospective ...
Palacios B - - 1997
The effects of endothelin-1 and vehicle (0.9% NaCl) on mean arterial pressure, heart rate, mean circulatory filling pressure, systemic arterial resistance, cardiac output and venous resistance were studied in four groups of pentobarbitone-anaesthetized rats, either in presence or absence of phentolamine. I.v. bolus injections of endothelin-1 at 0.5, 1 and ...
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