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 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We measured the action of dopamine given intravenously at dosage ranging from 2.5 to 320 micrograms/kg per min in closed chest anaesthetized dogs. Dopamine produced a dose-dependent increase in heart rate, cardiac index, mean arterial pressure, total peripheral resistance, pulmonary artery pressure, left ventricular end diastolic pressure, coronary flow and myocardial oxygen consumption. At dopamine dosage of 80-320 micrograms/kg per min, the coronary vascular resistance, the stroke volume index, the efficiency of heart work and the central venous pressure are all decreased. The maximum effect of dopamine on the circulation was seen at a dose between 40 and 80 micrograms/kg per min.
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PMID:Dopamine effects on circulation and myocardial oxygen supply. 26 1

The cardiovascular effects of a 12-week endurance training regimen were studied among normally active and healthy prepubertal children. Twenty-six 8- to 12-year-old children (20 boys and 6 girls) volunteered and 10 acted as control subjects. The training regimen consisted of distance running for progressively longer periods (from 10 to 35 min) 2 to 3 times per week, with 2 additional sessions per week devoted to running games. Those who were trained ran a cumulative average distance of 95.6 km (58.9 miles). Intensity of work was assessed from running pace and heart rate. The target workout intensity was 75% to 80% of aerobic capacity (Vo2 max). Growth and development accounted for increases in height, weight, body circumferences, and diameters, and fat-free body weight. Heart rate (HR) during submaximal workloads, both running and walking, decreased in the trained group (p less than 0.01) and (p less than 0.05). HRmax did not change, but Vo2 max increased significantly (average 7%) in the trained group but not in the controls. No significant change attributable to training was found for submaximal cardiac output, stroke volume, or arteriovenous oxygen difference. The Vo2 max value before conditioning was a relatively poor predictor of the magnitude of improvement in functional capacity, but those with higher initial Vo2 max logged more cumulative training mileage. It was concluded that prepubertal children respond to an endurance training regimen by improving their running capacity, which is, to a limited extent, associated with increased aerobic capacity.
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PMID:Effects of an endurance training regimen on assessment of work capacity in prepubertal children. 27 Sep 49

Some circulatory effects of thoracic epidural analgesia (TEA) were investigated in splenectomized, open-chest sheep during normoxia, hypoxia and isoproterenol administration. During normoxia, TEA caused comparatively marked reductions in systemic arterial blood pressure, total peripheral resistance and cardiac output. A fall in heart rate was not compensated for by any rise in stroke volume. Myocardial contractility (LV dd/dt/IP) was not affected by TEA. The proportion of cardiac output diverted to the blocked area was markedly increased. Compensatory vasoconstriction was not observed within the unblocked area in six out of nine animals. Myocardial blood flow showed a pronounced reduction in accordance with the calculated changes of heart work, so that myocardial oxygen extraction remained unchanged. Studies under hypoxia revealed that cardiac responses to hypoxia in the sheep are mediated chiefly by neurogenic factors. TEA abolished the hypoxia-induced rise in heart rate but did not affect the increase in pulmonary vascular resistance caused by hypoxia. The administration of isoproterenol during TEA increased systemic arterial blood pressure, but due to further fall in total peripheral resistance it was not fully normalized. Cardiac output and heart rate increased markedly. Myocardial oxygen consumption and blood flow increased but did not reach control levels.
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PMID:Cardiovascular effects of epidural analgesia. I. Thoracic epidural analgesia. An experimental study in sheep of the effects on central circulation, regional perfusion and myocardial performance during normoxia, hypoxia and isoproterenol administration. 27 92

In eight patients undergoing cardiac surgery for aortic and/or mitral valvular disease, mean arterial blood pressure (MAP), central venous pressure (CVP), cardiac index (CI), stroke index (SI), pulmonary capillary wedge pressure (PCWP), and pulmonary arterial mean pressure (PAMP) were measured after premedications with diazepam-scopolamine (I), after breathing 100% oxygen (II), and on controlled respiration (III) after induction of anaesthesia with enflurane-O2, and endotracheal intubation facilitated by succinylcholine. All measurements were done prior to surgery. Enflurane anaesthesia was found not to affect cardiac index. The average SI decreased by 27%, but was compensated for by an average increase in heart rate (HR) of 33%. The average systemic vascular resistance (SVR) decreased by 14%. All other measured parameters were found to be unaffected by enflurane-O2 anaesthesia. It is concluded that the cardiovascular stability observed in healthy young normals during enflurane anaesthesia is preserved in patients with moderate to severe heart failure, making enflurane an anaesthetic agent well suited for patients with cardiac disease.
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PMID:Haemodynamic effects of enflurane in patients with valvular heart disease. 27 53

In cardiosurgical patients the haemodynamic effects of dobutamine 2.5 microgram/kg . min and 5 microgram/kg . min dobutamine were investigated during neuroleptanalgesia, intra- and immediately postoperatively. Intraoperative measurements were performed in 8 coronary surgical patients each after sternotomy and pericardiotomy, but before the aortocoronary venous bypass operation. The following haemodynamic parameters increased significantly: cardiac index (2.5 microgram/kg . min: 2.6 leads to 2.1 1/min . m2; 6 microgram/kg . min: 1.5 leads to 2.24 1/min . m2), heart rate (80 leads to 91 min-1; 86 leads to 107 min-1), stroke index (16%, 27%), mean arterial pressure (70 leads to 90 mm Hg; 70 leads to 93 mm Hg), mean pulmonary arterial pressure (8%; 14%), LV dp/dtmax (72%; 121%) and calculated myocardial oxygen consumption Eg (35%; 52%). Changes in right (PRA) and left ventricular filling pressure (PLVED), in total systemic resistance and total pulmonary vascular resistance were not significant. Postoperative measurement immediately after open heart operations (ASD-correction n = 5, aortocoronary venous bypass (n = 3) in neuroleptanalgesia too, showed the same haemodynamic results as intraoperatively before correction of coronary stenosis. Only a few premature ventricular beats were observed in 3 patients and there were no changes in S-T segments during dobutamine infusion. In another group of 15 patients selective vascular responses to an infusion of 10 microgram/kg . min dobutamine were examined during steady state cardiopulmonary bypass excluding heart and lungs from the circulation. No relevant direct influence on the arteriolar resistance vessels and the venous capacitance vessels were found. In a dose range of 2.5--5.0 microgram/kg . min dobutamine proved to be a potent inotropic agent causing almost no peripheral and relatively little positive chronotropic effects. But the increase in heart rate was more pronounced than in other clinical investigations in conscious patients, which might be due to an attenuation of vagal reflex by anaesthesia. The results indicate, that dobutamine may be a valuable drug in the treatment of intra- and postoperative low output syndromes especially in patients with coronary heart disease.
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PMID:[Haemodynamic and vascular effects of dobutamine during and after open heart operations (author's transl)]. 31 59

The haemodynamic effects of dobutamine (2 microgram/kg . min and 4 microgram/kg . min) and dopamine (4 microgram/kg . min and 8 microgram/kg . min) were studied in 17 patients with coronary artery disease prior to coronary bypass surgery. The study was performed under general anaesthesia (modified neurolept analgesia) and controlled ventilation. Dopamine improved cardiac index significantly, increased mean aortic pressure slightly while heart rate and total peripheral resistance remained unchanged. Dobutamine failed to increase cardiac and stroke index significantly, but increased mean aortic pressure distinctly due to an elevated total peripheral resistance. Both catecholamines increased left ventricular filling and mean pulmonary artery pressure. The HR x ASP-product which is closely related to left ventricular oxygen consumption was found to be augmented to a greater extent during dobutamine. For the above reasons dopamine should be favoured for increasing cardiac output in patients undergoing aortocoronary bypass surgery. Our study does not confirm earlier results which have shown dobutamine to be the preferable catecholamine. The possible reasons for this discrepancy are discussed.
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PMID:[The haemodynamic effects of dobutamine and dopamine in patients with coronary artery disease. A study performed under general anaesthesia (author's transl)]. 31 60

Time-compressed Fourier analysis of the electroencephalogram has proven to be a useful analytical procedure during anesthesia and surgery which simplifies data interpretation by presenting the EEG in a time-compressed frequency domain rather than the conventional time domain. This method of data analysis graphically accentuates the electroencephalographic correlates of ischemia-induced cerebral dysfunction and other cerebral oxygen consumption abnormalities. The ability to accentuate trends in frequency and power is derived from sequential plotting of spectra to produce a graph with three dimensional axes of frequency, time, and power. In carotid endarterectomies the system has proven more useful than the conventional EEG in assessing the need for a vascular shunt to maintain internal carotid flow during endarterectomy. In open-heart surgery time-compressed EEG spectral analysis has allowed early recognition of cerebral ischemia resulting from arterial hypotension and venous hypertension. Five cases are presented which demonstrate the ability of our system to reflect developing cerebral ischemia.
Stroke
PMID:Monitoring of cerebral perfusion during anesthesia by time-compressed Fourier analysis of the electroencephalogram. 32 37

In a review the specific reaction of the cardiovascular system of children and youth to actual athletic stress and on a staying power training is dealt with. The present knowledge is imperfect because the medicine had a cautious opinion of the maximum stress of the infantile heart till recent times, and children training systematically were exceptions. The examination of the cardiovascular system of training children is complicated as far as the effects of training are mostly equal in direction like growth, maturing, and development effects. But it is evident that the infantile circulation system is well adaptable to staying power results. During training a cardiac enlargement surpassing the growth rate is arising. Under the condition of rest the heart of the trained child is more subjected to vagal control with the appropriate functional consequences. By submaximum stress an economization of the function can be observed. During stress a stronger inotropia with increased stroke volume and better oxygen absorption is stated. The post-stress phase is characterized by an accelerated return of the deflected functions to the zero level. Furthermore statements are made about the specific ECG of sporting children, about the problems of sports at heart diseases, about acceleration and retardation as well as about the transformation of physiologic knowledge into methodical conceptions for training.
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PMID:[Effect of training in sports on the cardiovascular system of children and adolescents]. 34 6

The immediate haemodynamic effects of the addition of a positive end-expiratory pressure (PEEP) of 5 cmH2O has been studied in eleven patients undergoing artificial ventilation for respiratory failure. Mean cardiac output fell from 6.0 to 5.5 litres/min. This was due to a similar decrease in stroke volume. Individual patients showed greater, though short-lived, changes. There was also a statistically significant increase in central venous pressure (from 8-9 cmH2O) and peripheral resistance (from 1280 to 1380 dyn sec cm-5) associated with the application of PEEP. Overall changes in heart rate and mean arterial blood pressure were insignificant. Arterial oxygen tension increased in the majority of patients but the mean figure was unchanged. Mean oxygen delivery to the tissues fell from 830 to 780 ml/min.
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PMID:Positive end-expiratory pressure. Immediate haemodynamic effects during artificial ventilation. 34 29

Twelve patients with clinical and hemodynamic evidence of severe congestive heart failure, unresponsive to the usual therapy of salt restriction, oxygen, bed rest, digitalis, and massive doses of diuretics, were studied during a control period and after intravenous dopamine. Seven patients survived and 5 died with intractable failure and shock despite transiently improved hemodynamic indices. At control period and after optimal dose of dopamine, there were no significant changes in heart rate (HR) and mean systemic arterial pressure. The mean pulmonary artery (PA) and pulmonary capillary wedge (PCW) pressures decreased slightly. Cardiac index (CI), stroke volume (SVI), and stroke work indices (SWI) rose (p less than 0.005) from the control values of 1.4 +/- 0.1, 15.3 +/- 5, and 13.6 +/- 1.7 to 2.2 +/- 0.1, 24.1 +/- 4, and 24 +/- 2.3, respectively; pulmonary arteriolar (PAR), total pulmonary vascular (TPVR), and systemic vascular (SVR) resistances fell (p less than 0.01). Urine output increased from 13.5 ml/hr before to 58.2 ml/hr after dopamine (p less than 0.005). After 24 and 48 hr of dopamine, in addition to the above hemodynamic changes, PA pressure fell from 38 +/- 4 to 33 +/- 3 and 28 +/- 2, and PCW from 30 +/- 2 to 24 +/- 3 and 18 +/- 3 (p less than 0.05). Compared with nonsurvivors, survivors had significant decreases in PA and PCW pressures, PAR, and TPVR and an increase in SWI. These data indicate that dopamine is effective in some patients with refractive congestive heart failure associated with acute oliguric renal failure and that the prognosis may be improved.
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PMID:Hemodynamic effects of dopamine in patients with resistant congestive heart failure. 35 38


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