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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The data on one of sepsis variations, bacterial or endotoxin shock (BS) are presented. BS is caused by gram-negative flora among which the first place belongs to E. coli, but may also be caused by gram-positive bacteria. BS is characterized by an acute onset with chills, hyperthermia, leukocytosis and early development of circulatory collapse which may cause early death of the patient. The direct of mediated effect of endotoxin on the vascular wall causing paralytic distention of the microcirculatory bed with deposition of the blood in it is recognized in the pathogenesis of BS. Subsequently, under conditions of hypoxia and acidosis disorders of hemocoagulation develop in the form of disseminated intravascular coagulation which may result in cortical necrosis of the kidneys, necrosis and apoplexy of the adrenals, hypophysis, acute ulcers in the gastrointestinal tract, necroses and hemorrhages in some other organs.
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PMID:[Bacterial (endotoxic) shock]. 699 29

One hundred forty-two deaths among 743 men ages 50 - 65 years who had been examined and followed 5 - 10 years were investigated and classified on the basis of clinical information from medical and non-medical observers, ECGs and autopsies. A classification based on the condition of the circulation immediately before death appears to be most relevant to studies of sudden death. In 58% of the cases, the subjects collapsed abruptly and his pulse ceased without prior circulatory collapse (arrhythmic death); in 42%, the pulse ceased only after the peripheral circulation had collapsed (deaths in circulatory failure). Thirty-three percent of arrhythmic deaths and 10% of deaths in circulatory failure occurred in a setting of clinical evidence of acute ischemic heart disease (p less than 0.005). Forty-five percent of arrhythmic deaths were preceded by chronic congestive heart failure without circulatory collapse. Ninety-three percent of final illnesses that lasted less than 1 hour ended in arrhythmic deaths; 74% lasted more than 1 day ended in deaths in circulatory failure (p less than 0.001). Eighty-eight percent of deaths that occurred outside of the hospital were arrhythmic; 71% of deaths that occurred in the hospital were deaths in circulatory failure (p less than 0.001). Ninety percent of deaths in which the primary cause of the final illness was heart disease were arrhythmic; 86% of deaths in which the primary cause was other than heart disease were deaths in circulatory failure (p less than 0.001). Ninety-one percent of deaths precipitated by an acute cardiac event were arrhythmic; 98% precipitated by acute respiratory obstruction, hemorrhage, infection, stroke or other noncardiac events were deaths in circulatory failure (p less than 0.001).
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PMID:Clinical classification of cardiac deaths. 705 67

The hemodynamic effects of dopamine (DPM) and dobutamine (DBM) were compared in 13 patients with acute cardiogenic circulatory collapse. All patients presented with acute pump failure and inadequate systemic perfusion, and most were hypotensive. Nine patients had an acute myocardial infarction (AMI); the other four patients had an acute decompensation of a previously stable ischemic cardiomyopathy, and presented with a low-output syndrome in the absence of documented AMI. Patients were studied with a randomized single crossover design using each patient as his own control. Both drugs were given at doses of 2.5, 5, and 10 micrograms/kg/min for periods of 10 minutes at each dose while hemodynamics were monitored. No other vasoactive drugs were used during the study. Because of advanced age or severe peripheral vascular disease, no patient was considered suitable for intra-aortic balloon counterpulsation. There were no significant differences between the two drugs with regard to heart rate, mean-arterial pressure, systemic vascular resistance, stroke work index, or mean right atrial pressure. DBM improved stroke index and cardiac index significantly (p less than 0.05) more than DPM at doses of 5 micrograms/kg/min. DPM increased left ventricular filling pressure (LVFP) more than DMB at 5 micrograms/kg/min (p less than 0.001) and at 10 micrograms/kg/min (p less than 0.05). Although both DPM and DBM are useful in acute cardiogenic circulatory collapse, there appear to be important differences in their effect on LVFP and in the mechanisms whereby they increase blood pressure.
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PMID:Comparative hemodynamic effects of dopamine and dobutamine in patients with acute cardiogenic circulatory collapse. 708 Oct 40

To determine the causes of cardiac failure during cardiac tamponade in man, we studied left ventricular volume and function in eight patients during pericardiocentesis using gated equilibrium radionuclide ventriculography. In the seven patients with clinical and hemodynamic evidence of cardiac tamponade, end-diastolic and end-systolic volumes increased progressively as the initial 500 ml of fluid were removed; the most marked increase occurred during the removal of the first 200 ml of pericardial fluid. After removal of 500 ml of pericardial fluid, end-diastolic volume increased from 52 +/- 8 ml to 111 +/- 13 ml (p less than 0.05) and end-systolic volume from 17 +/- 5 ml to 34 +/- 7 ml (p less than 0.05). Additional aspiration of fluid resulted in no further changes in left ventricular volume. The ejection fraction averaged 70% before removal of fluid and was unchanged by pericardiocentesis. In the one patient who did not have hemodynamic evidence of tamponade, there were only minor changes in left ventricular volumes and ejection fraction. These data suggest that pump function of the left ventricle is well preserved in cardiac tamponade, and that the diminution in stroke volume and consequent cardiovascular collapse seen in tamponade are due to marked underfilling of the ventricle.
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PMID:Left ventricular volume and function during relief of cardiac tamponade in man. 708 1

Ten cases of death due to heat stroke are described. They were all young men who collapsed during running exercise or route march and died in hospital later. Post-mortem examination was carried out in all cases. Death was due to disseminated intravascular coagulation with widespread microthrombus formation and coagulative necrosis involving many organs. Meteorological studies showed that at the time of the collapse the environmental temperature was higher than average although it may have been in the morning or evening.
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PMID:Acute heat stroke deaths. 722 95

The effect of thermal stress on healthy mongrel dogs was studied at ambient temperatures of 40, 45 and 50 degrees C. At 40 degrees C there was a linear increase in cardiac output, heart rate and oxygen consumption and cardiovascular failure did not occur even after 6 hours of exposure. At 45 degrees C the circulation was hyperdynamic up to 60 min but at 90 min there was a steep fall in oxygen consumption, cardiac output, stroke volume and mean arterial pressure whereas heart rate increased significantly. At 50 degrees C the hyperdynamic changes reached peak values in 30 min; but by 60 min, there was a collapse of cardio-vascular function leading to rapid decline and ultimate death. It seems that the point at which there is a sudden fall in oxygen consumption, cardiac output, stroke volume and mean arterial pressure could be taken as an index of significant heat injury.
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PMID:Cardiovascular changes during varied thermal stress. 738 May 25

Heat stroke in distance runners is increasing in frequency. A case is reported of a 41-year-old man who collapsed during a 10-km "fun run" held when the temperature was 31.6 degrees C and the humidity 80%. Acute renal failure (serum creatinine level 1530 mumol/l [17.3 mg/dl]), rhabdomyolysis, disseminated intravascular coagulation and hepatic damage complicated the clinical picture. Repeated peritoneal dialysis and one cycle of hemodialysis because of a very high serum level of uric acid (1.23 mmol/l [20.7 mg/dl]) were required. Although the illness was prolonged, recovery was almost complete, and 4 months after the man's collapse the serum creatinine level had fallen to 133 mumol/l (1.5 mg/dl).
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PMID:Exertional heat stroke: the runner's nemesis. 738 6

Accidental hypothermia, a core temperature below 34 degrees C., is frequently fatal, particularly in the ill and elderly. Traditional treatment methods result in reported mortalities of between 45 and 100 per cent. Despite these terrible statistics, advocates of slow rewarming persist. They cite the shock and vascular collapse which can occur with peripheral dilation as reasons to avoid rapid external rewarming. Isolated successes using internal core rewarming, such as hemodialysis or cardiopulmonary bypass, are spectacular but not practical in the usual clinical situation. By combining methods used for the resuscitation of burn injury with the treatment principles for frostbite, a highly effective treatment protocol results. Agressive fluid resuscitation, rapid immersion rewarming and careful systematic monitoring have been used to treat ten consecutive patients without a single death. Concomitant problems of alcoholism, stroke, myxedema, tuberculosis and paraplegia were also treated. Rapid external rewarming by immersion can result in a low mortality in patients with severe hypothermia.
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PMID:Accidental hypothermia treated without mortality. 740 8

Intrinsic features of the pumping process of a pneumatically driven ventricular assist device (VAD) and the effects of different types of pneumatic drivers upon its performance were investigated in vitro by analysing the pressure distributions within the device and the motions of the prosthetic valves. It was found that the stretching of the flexible, elastic diaphragm in both late systole and diastole initiates a pressure oscillation which directly affects the timing of the pumping process. The timing was also found to be dependent on the length and stiffness of the cannulae which link the VAD to the model circulation system. During the stretch-induced oscillation in late systole, the VAD housing experiences partial collapse due to fluid momentum effects, which tends to increase the effective stroke volume of the device, and reduce the amplitude of the pressure oscillation. Reducing the rising (falling) rate of driving pressures (dpd/dt) may not necessarily reduce the maximum rate of change of the blood chamber pressure (dpch/dtmax) but may upset the stability of the pumping process. This is because a minimum dpch/dtmax exists, which is determined by the stretch-induced oscillation. In order to minimize dpch/dtmax and to provide the device with a stable working condition, dpd/dt should match the dpch/dtmax.
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PMID:Pressure development within a sac-type pneumatically driven ventricular assist device. 779 82

A hydraulic pump with an adjustable stroke delivering up to 145 ml at 1 to 45 Hz has been used to ventilate adult pigs of a weight between 60 and 140 kg. After tracheotomy the curarized animals were connected to the pump by a metallic tube through which a bias flow was directed. This flow (FiO2 0.35) was humidified by a special ceramic device and aspirated at the distal end of the tube. It was demonstrated that under these conditions gaz exchange was well maintained with oscillations between 15 and 35 Hz. Higher frequencies were needed for the heavier animals. Blood gas measurements of samples from segmental pulmonary veins demonstrated regional differences in gas exchange. These could be modified by adjusting the oscillation frequency. Reinhalation of gas could be prevented by an increase of the bias flow. Alveolar recruitment by initial pulmonary inflation by a pressure of 18 +/- 2 cm H2O is required for adequate oxygenation. Maintenance of adequate elimination of CO2 required a bias flow of 35 +/- 5 l/min. Mean pressure in the airways was maintained at 12 +/- 1 cm H2O. This pressure determines the value of PaO2. Ordinary endotracheal tubes tend to collapse during the sucking phase of the pressure cycle. Rigid or armed tubes are required. They must allow for aspiration of the bias flow from the distal end of the tube.
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PMID:[Ventilation by high frequency oscillations in adults. An experimental study of conditions and methods]. 781 53


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