1. Haemodynamic and metabolic effects of intravenous infusion of adenosine, an endogenous vasodilator, were studied in healthy humans. 2. Catheters were inserted into pulmonary and brachial arteries and into the hepatic and subclavian veins. Cardiac output was determined according to the Fick principle, and splanchnic blood flow was measured by ...

Serial measurements of apparent liver blood flow and cardiac output were performed in 12 women at 12-14, 24-26 and 36-38 weeks of pregnancy and then at 10-12 weeks after delivery. Apparent liver blood flow was calculated from indocyanine green clearance. Cardiac output was measured by Doppler and cross-sectional echocardiography at ...

The time constant for heat transfer may affect exact determination of cardiac output with Swan-Ganz catheters. Commercially available Swan-Ganz catheters are provided with thermistors with varying time constants. Current monitoring of cardiac output is not corrected for these time constants, so the conventional method of determining cardiac output using the ...

Differences in effects on central haemodynamics, organ blood flow, and serum corticosterone were studied in 11 rats anaesthetized with midazolam/fentanyl/fluanisone (MFF) and 11 other rats anaesthetized with sodium pentobarbital. Compared with pentobarbital, MFF reduced aortic blood pressure by 25%, increased heart rate by 20%, and increased cardiac output by 80%. ...

1. We studied the effects of four doses of nimodipine (0.5, 1, 2 and 4 micrograms kg-1 min-1) on systemic haemodynamics and on regional vascular beds, in particular the cerebral circulation, in conscious pigs. 2. Nimodipine caused dose-dependent, probably reflex-mediated, increases in heart rate (42% with the highest dose) and ...

The purpose of this study was to examine the effects of dexmedetomidine, an alpha 2-adrenergic agonist, on cerebral blood flow and metabolic rate in dogs anesthetized with 0.64% isoflurane. After intubation and institution of mechanical ventilation, arterial, venous, pulmonary artery, and sagittal sinus catheters were inserted. Measurements of cerebral blood ...

We compared two techniques for measuring blood flow through portal-drained viscera (PDV) of beef steers and measured portions of cardiac output and total oxygen uptake attributable to PDV and hepatic tissues. Four steers (198 +/- 2 kg), equipped with chronic catheters in appropriate vessels, a transit-time ultrasound probe around the ...

High-flow cerebral arteriovenous fistulae are well known to present in the neonatal period with macrocephaly, cranial bruits and high-output cardiac failure. This report describes a newborn infant with such a clinical presentation, who had unilateral megalencephaly without macroscopic arteriovenous shunts. Ultrasound Doppler examination of the carotid and cerebral vessels showed ...

Thirty days after infection with the parasite Nippostrongylus brasiliensis, microcirculatory changes associated with worm allergen-induced anaphylactic shock in pentobarbital-anesthetized rats were studied. Allergen challenge decreased heart rate, mean arterial blood pressure, and cardiac output (CO) for 60 min, although CO increased markedly by 240 min. Blood flow (ml.min-1.g wet tissue-1) ...

Mice are commonly used for the study of human disease processes. However, techniques for measuring systemic and hepatic blood flow in mice have not been developed. We attempted the conventional technique of radiolabeled microsphere injection into the left ventricle, but difficulties were encountered, including unsuspected ventricular perforation and outflow obstruction ...

Traumatic brain injury affects systemic circulation as well as directly damages the brain. The present study examined the effects of fluid percussion brain injury on systemic hemodynamics and organ arterial blood flow in rats. Rats were prepared for fluid percussion injury under anesthesia. Twenty-four hours later, rats were anesthetized (1.0% ...

Interobserver reproducibility in deriving cardiac output by measuring aortic blood flow velocity and diameter with imaging and Doppler ultrasound was investigated in 20 healthy infants born at full term. Aortic diameter was measured in three ways. Mean blood flow velocity was measured at three sites with both continuous wave and ...

This paper presents data on the measurement of aortic flow (Qa) using an electromagnetic flowmeter and the measurement of pulmonary blood flow (Qep) using a single-breath technique employing freon-22 as the soluble marker gas. The purpose was to assess the potential of a single-breath technique (using freon) as an effective ...

The hemodynamic effects of the calcium antagonist isradipine (code name PN 200-110) and the arteriolar vasodilator dihydralazine were compared in atherosclerotic (cholesterol-fed) and normal conscious rabbits with implanted catheters. Regional blood flows were measured using the microsphere technique. Cardiac output and blood flow to several organs, especially to the gastrointestinal ...

After a change in cardiac output, the magnitude of potential blood volume redistribution was investigated in 10 dogs anesthetized with chloralose. All of the venous return was pumped into a reservoir, using servocontrolled pumps to maintain fixed superior and inferior vena cava pressures. The cardiac output was set at various ...

A method for simultaneous determination of cardiac output and regional blood flow distribution in a chronically instrumented, unrestrained rat preparation for different experimental conditions (i.e. conscious, free movement; general anesthesia) and in an experimental chronic liver injury model is described. The use of a modified radioactive microsphere reference sample method ...

Early postburn changes in central haemodynamics, organ blood flow distribution and morphology of the gastric mucosa were studied using a standarized thermal skin injury model. Organ blood flow and cardiac output were determined using radioactive microspheres. In the control animals no marked changes in cardiac output or organ blood flow ...

The systemic and regional hemodynamic effects of the centrally acting putative 5-HT1A receptor agonist flesinoxan (3, 10, 30, and 100 micrograms/kg) were investigated in the anesthetized cat and compared with those of 8-hydroxy-2(di-n-prophylamino) tetralin (8-OH-DPAT 3, 10, 30, and 100 micrograms/kg) and clonidine (0.3, 1, 3, and 10 micrograms/kg). Cardiac ...

We performed cardiac blood-pool scintigraphy using technetium-99m diethylenetriaminepentaacetic acid human serum albumin [( 99mTc] DTPA-HSA), a newly developed blood-pool agent, in 31 patients with various heart diseases and evaluated its clinical usefulness in comparison with the conventional in vivo 99mTc red blood cell (RBC) labeling. Excellent cardiac blood-pool images were ...

Thoracic bioimpedance cardiac output (Qtbi) was measured at 1-min intervals in 27 volunteers before, during, and after withdrawing 500 ml (3.7 to 8.5 ml/kg; mean 5.8) of blood. The effects of passive leg raising (PLR) and standing on Qtbi were measured before and after blood withdrawal. Arterial oxygen saturation (SaO2), ...

The effect of aminophylline on diaphragmatic blood flow was investigated in two groups of newborn piglets. Six animals were studied during spontaneous breathing and seven additional animals were paralyzed and ventilated to assess the effect of aminophylline on blood flow to the nonworking diaphragm. Arterial blood gases and pH, cardiac ...

The acute hemodynamic effects of an intravenously (i.v.) injected poly(ethylene oxide), Polyox WSR N-60K (dose 50 mg/kg), were studied in the open-chest rat anesthetized with sodium pentobarbital. The injectate is one of four drag-reducing polymers known to augment in vitro blood flow under a constant pressure gradient; the others are ...

In patients with cirrhosis and portal hypertension, propranolol administration reduces heart rate and cardiac output and diminishes portal pressure and collateral blood flow. However, there is little information on the possible effects of propranolol on hepatic artery blood flow. The present study addressed this question in 12 cirrhotic patients with ...

The lack of a reliable quantitative description of blood flow in man has hampered the development of accurate biokinetic models of essential elements, drugs, imaging agents, and carcinogens. In this paper we review and analyse data on blood flow and identify representative percentages of cardiac output and absolute blood flow ...

Although much has been written on the response of the heart to various intracerebral events including seizures, ischemia, intracerebral, and subarachnoid hemorrhage, less is known of the cerebral response to altered cardiac rhythm, cardiac failure, and cardiac arrest. The latter may alter central neuronal activity, cerebral blood flow, or cause ...

Alterations in blood flow distribution in streptozotocin-induced diabetes in the rat were examined. Blood flow between tissues was estimated by the distribution of radiolabeled microspheres, and a second series of experiments examined skeletal muscle microcirculation by in vivo microscopy. Studies were performed in anesthetized rats 1-8 wk after induction of ...

The hemodynamic responses to early enteral feeding were assessed with fluid-resuscitated, 30% total body surface area-burned guinea pigs fed by means of tube gastrostomies. Regional blood flow and cardiac output were determined by a reference sample method, injecting 15 microns radiolabeled microspheres. During the initial 24 hours after burn injury, ...

Thirty-one fetuses with growth retardation were studied by Doppler estimation of the cardiac output from each side of the fetal heart. Asymmetrical growth retardation was diagnosed in 16 fetuses by a head to abdominal circumference ratio above the 95th centile. In the 15 fetuses with symmetrical growth retardation, the distribution ...

To investigate the effects of enkephalins on cardiac output and regional blood flow, we administered D-Ala-D-Leu-enkephalin (DADLE) intracisternally (ic) to 14 chronically instrumented unanesthetized dogs. Measurements were made at base line, 20, 45, and 75 min after DADLE (25 or 125 micrograms/kg) and 15 min after naloxone (5 micrograms/kg ic). ...

With two-dimensional echocardiography and Doppler ultrasound, we demonstrated high-output cardiac failure in three fetuses with large sacrococcygeal teratomas. All fetuses had normal cardiac structure, dilated ventricles maintaining a normal fractional shortening index, a dilated inferior vena cava reflecting the increased venous return from the lower body, pericardial and pleural effusions ...

The conjunctival oxygen tension (CjO2) sensor is a non-invasive, continuous index of oxygen delivery in the haemodynamically unstable patient. Human and animal studies have indicated that CjO2 reflects cerebral blood flow and oxygenation. Simple insertion, rapid stabilization and reaction time less than 60 s allow use in the initial stages ...

A newly developed, flow-directed, Doppler pulmonary artery catheter, capable of measuring instantaneous and continuous cardiac output, was evaluated in both an in vitro pump model and an animal model. Quantitative flow was calculated with use of the instantaneous, space-average velocity (obtained from the velocity profile) and the instantaneous area (obtained ...

The leukotrienes are a group of biologically active products of arachidonic acid metabolism that have been demonstrated to possess the capability to alter vascular reactivity as well as vascular permeability when applied topically to tissues or infused into the vascular bed of various organs. These biologic effects of the exogenous ...

The use of disopyramide is often limited because of adverse hemodynamic or electrophysiologic side effects. We compared the S(+) and R(-) enantiomers of disopyramide to the clinically used racemic mixture in a canine blood superfusion model. Eighteen support animals (group I) provided extracorporeal blood superfusion of isolated canine cardiac Purkinje ...

End-tidal PCO2 (PetCO2) is a quantitative indicator of pulmonary blood flow generated by precordial compression and therefore predicts resuscitability during CPR. A striking increase in PetCO2 follows return of spontaneous circulation. Since PaCO2 is closely related to alveolar PCO2 (PACO2) and therefore PetCO2, we hypothesized that PaCO2 may itself serve ...

The capacity of L-649,923--sodium (beta S, gamma R*)-4-(3-(4-acetyl-3-hydroxy-2-propylphenoxy)-propylthio)-ga mma- hydroxy-beta-methylbenzene butanoate--to block vascular receptors of leukotriene D4 (LTD4) was examined in the conscious rat. Hindquarter (HQ), renal, and mesenteric blood flow and vascular resistance were evaluated in the conscious rat chronically equipped with miniaturized Doppler probes for organ blood flow ...

Electromagnetic flow (EMF) quantification of total cardiac stroke flow is not feasible for most elasmobranchs because the vascular anatomy precludes probe placement adjacent to the heart and proximal to all afferent branchial arteries (aba). Most previous studies report a fractional cardiac flow, made with the EMF probe placed on the ...

The progress in organ transplantation has led to a rise in the demand for organs. Paediatric intensive care units are the main source for obtaining organs. Every "brain dead" patient should be regarded as a potential donor. General contraindications to organ donation are: systemic viral or bacterial infections and extra-cerebral ...

Water immersion produces a marked diuresis, natriuresis, and kaliuresis in association with suppression of the renin-aldosterone system. These effects are mediated primarily by an increase in central blood volume. Consequently, this redistribution and the resultant marked increase in cardiac output is associated with alterations in the circulating levels of several ...

The current emphasis on the acquisition of physiological data by noninvasive means for mass medical screening and patient monitoring has increased interest in the use of electrical impedance for the measurement of physiological events. The technique has gained some degree of acceptance for monitoring respiration (Baker & Geddes, 1970), and ...

A totally self-contained instrument for the measurement of cardiac output is described. The microcomputer controlled instrument is based upon the principles of thermodilution and is capable of making cardiac output determinations on a minute by minute basis. A bolus of heat is delivered to the blood via a resistive heating ...

Shock is, as before, among one of the most serious pathologic states threatening patient's life in spite of considerable progress in its treatment in the recent ten years. The immediate causes of shock may be a decrease of cardiac output, increase of volume of vascular bed or interaction of them ...

There is considerable evidence suggesting that substrate (e.g., oxygen) distribution and utilization are abnormal in the setting of acute respiratory failure from the adult respiratory distress syndrome (ARDS). The mechanisms that may explain this anomalous relationship include: redistribution of cardiac output resulting in the nonuniform delivery of substrate to regional ...

Acute left ventricular failure was induced in anaesthetized dogs by repeated embolization of the left coronary artery with 57 micron microspheres. Tissue blood flow was measured with isotope-labelled microspheres in two stages of heart failure. With increasing doses of embolizing solution there was a progressive decline in systemic blood pressure ...

The continuous measurement of cardiac output in conscious rats is difficult. Previously, Doppler flow probes have been applied to the ascending aorta by means of silicone cuffs. The placement of these cuffs can conceivably introduce errors engendered by the destruction of nerve fibers that are important in cardiac autonomic innervation. ...

The distribution of cardiac output (CO) was studied in conscious rats during hyperbaric oxygen (HBO) exposure to 5 bar for 60 min. Heart rate (HR) and arterial blood pressure (ABP) were continuously recorded. Organ blood flow and CO were measured during control, after 5 and 60 min HBO by the ...

During cardiac arrest (no flow) and CPR (low flow), the onset of myocardial ischemia is followed by myocardial respiratory acidosis. Myocardial contractility is more decreased by respiratory than by metabolic acidosis. We demonstrated in a porcine model of cardiac arrest and in human patients increases in mixed venous PCO2 during ...

The purpose of the present study was to examine the effect of amrinone, a drug known to augment cardiac output and dilate peripheral vascular beds, on diaphragm blood flow. Studies were performed on 12 anesthetized mechanically ventilated dogs in which strips of left costal diaphragm were developed in situ. Strip ...

Regional blood flow and the distribution of cardiac output is an important aspect of the pathophysiology and pharmacology of human congestive heart failure. This study presents the cumulative experience and data from our laboratories with specific reference to (1) the regional blood flow responses, some rather unique, to various vasodilators ...

This study was designed to determine the short-term residual effects of ether anesthesia on hemodynamics and blood flow distribution in the rat. Eighteen male Sprague Dawley rats were instrumented and allowed to recover for at least 2 days before beginning the experiment. Using microspheres, cardiac output, and blood flow distribution ...