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

To examine the right ventricular response to acute respiratory failure, serial studies of biventricular performance were analysed in 34 such patients, specifically detailing the role of associated underlying disease. During the initial study, the 34 patients with acute respiratory failure had a higher right ventricular end-diastolic volume than the control group (+21%), associated with a decrease in right ventricular ejection fraction, abnormalities which tended to return to normal values in the 15 survivors. In the 9 patients who died of refractory hypoxemia with severe pulmonary hypertension, the right ventricular dilation allowed to maintain stroke volume. In contrast, in 8 patients who died of septic shock, biventricular function was progressively altered (right and left ventricular ejection fraction = -37% and -35%). In 4 patients who died of cardiogenic shock (viral myocarditis), the cardiac function was the lowest (right and left ventricular ejection fraction = -59% and -60%). Only patients with acute respiratory failure associated with septic shock or viral myocarditis are unable to maintain their stroke volume.
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PMID:Right ventricular performance in patients with acute respiratory failure. 340 90

Nineteen critically ill patients with acute respiratory failure were studied to compare the hemodynamic effects of continuous positive-pressure ventilation (CPPV) and high-frequency jet ventilation (HFJV) at comparable levels of alveolar ventilation. Patients were divided into three groups: Group 1 included seven patients without circulatory shock in whom mean airway pressure (Paw) was slightly higher during CPPV than during HFJV (17.3 +/- 3.0 vs. 13.0 +/- 2.9 mmHg); Group 2 included six patients without circulatory shock in whom HFJV and CPPV were compared at the same level of Paw (19.2 +/- 5.0 mmHg); Group 3 included seven patients with circulatory shock in whom HFJV and CPPV were compared at the same level of Paw (16.0 +/- 3.9 mmHg). The following respiratory frequencies were used in HFJV: Group 1, 200 +/- 76 beats/min; Group 2, 238 +/- 103 beats/min; Group 3, 286 +/- 149 beats/min. In all patients comparable levels of PaCO2 were obtained with CPPV and HFJV. In Group 1 patients, mean arterial pressure, cardiac index, and stroke index were significantly higher during HFJV. In Group 2 patients, no significant difference was found between HFJV and CPPV. In Group 3 patients, the following hemodynamic variables were significantly higher during HFJV: mean arterial pressure (71 +/- 24 vs. 84 +/- 23 mmHg), cardiac index (3.6 +/- 1 vs. 4.1 +/- 1.41 X min-1 X m-2), and oxygen delivery (403 +/- 93 vs. 471 +/- 124 ml X min-1 X m-2).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hemodynamic effects of high-frequency jet ventilation in patients with and without circulatory shock. 353 72

The application of lower body positive pressure (LBPP) of approximately 40 Torr was used to increase cardiac index (CI) in eight patients with acute respiratory failure (ARF) during positive end-expiratory pressure (PEEP) ventilation. The effects of LBPP on hemodynamics and gas exchange were compared with those of dopamine at the same level of CI without blood volume expansion. LBPP increased CI via an increase in stroke index without associated tachycardia, whereas dopamine combined both effects. A positive linear relationship (r = 0.82) was evidenced between CI and right atrial pressure (Pra) during application of LBPP according to the Frank-Starling mechanism, whereas dopamine did not increase Pra. The increase in CI with dopamine was associated with a significant rise in venous admixture (r = 0.84, P less than 0.001), whereas no such effect was observed with LBPP (r = 0.088). Changes in venous admixture were directly related to changes in mixed venous O2 pressure (PVO2) in both situations (r = 0.733, P less than 0.01), but the increase in PVO2 was more pronounced with dopamine than with LBPP (P less than 0.04). We conclude that LBPP can effectively counterbalance peripheral venous blood pooling during PEEP ventilation in humans with ARF and that changes in PVO2 appear as a major determinant of venous admixture in this setting.
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PMID:Lower body positive pressure vs. dopamine during PEEP in humans. 388 84

We investigated cardiopulmonary effects of dopamine in patients with acute respiratory failure. Specifically, we wished to test the hypothesis that left ventricular filling pressure (Pcwp) would increase when cardiac output (CO) increased with dopamine. Dopamine (range, 5.5 to 20 micrograms/kg/min) increased blood pressure (BP) (p less than 0.001) Pcwp, CO, and stroke volume (SV) (p less than 0.005). Mean Pcwp increased (p less than 0.005) 45% with dopamine, from 11 to 16 mmHg. Qs/Qt increased with dopamine in association with an increase in mixed venous O2 tension, and arterial O2 tension remained constant. In 8 of these patients, left ventricular end-diastolic volume (LVEDV) and end-systolic volume (ESV) were measured using scintigraphic techniques. The LVEDV increased (p less than 0.01) in each patient after the administration of dopamine, and the mean change was from 134 to 163 ml. Although BP and LV afterload increased in each patient, there was no consistent change in LVESV after dopamine administration, i.e., ESV decreased in 1 patient, remained constant in 3, and increased in 4. Accordingly, because afterload increased in all patients and ESV did not, dopamine probably increased contractility. Because EDV increased in all patients, we concluded that the increase in SV with dopamine is explained by a combination of inotropic and peripheral vascular effects.
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PMID:Effects of dopamine on cardiopulmonary function and left ventricular volumes in patients with acute respiratory failure. 647 90

To evaluate the possibility that an elevated right ventricular stroke-work index observed in acute respiratory failure correlates with less dead space ventilation, 20 patients requiring mechanical ventilation were studied. Ratio of physiologic dead space to tidal volume was used as an index of distribution of pulmonary perfusion. An inverse linear relationship was found between right ventricular stroke-work index and dead space ratio (r = -0.74, p less than 0.001). No correlation was present between cardiac index and dead space ratio. To evaluate the effects of other hemodynamic data on the distribution of pulmonary perfusion, the patients were divided into two groups based on a dead space ratio. Comparison of the two groups revealed right ventricular stroke-work index was significantly higher in the low dead space ratio group (p less than 0.001). There were no differences in cardiac index, pulmonary-artery pressure, or right atrial pressures. These data suggest that elevated right ventricular stroke-work index in acute respiratory failure is associated with more even distribution of pulmonary perfusion, and that patients with a high dead space ratio were characterized by right ventricular dysfunction when compared to patients with a low dead space ratio.
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PMID:Right ventricular stroke-work. An index of distribution of pulmonary perfusion in acute respiratory failure. 664 6

The effect of profound hypercapnia on acute hypoxic respiratory failure is evaluated. Eight dogs were subjected to oleic acid-induced acute respiratory failure. Four dogs were ventilated normally, and four dogs were made hypercapneic by rebreathing exhaled CO2. In the hypercapneic animals, heart rate and alveolar-arterial oxygen difference were significantly lower than in normocapneic animals, while mixed venous O2 cardiac index, oxygen delivery index, stroke volume index, and left ventricular stroke work were significantly higher. Mean arterial pressure was maintained at preinjury levels. Pulmonary and systemic vascular resistance increased in both experimental groups. There was no significant difference between groups for gravimetric determination of lung water. Cardiopulmonary performance in acute respiratory failure is improved with hypercapnia. This may be related to CO2-induced catecholamine release.
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PMID:The hemodynamic effect of profound hypercapnia on acute hypoxic respiratory failure. 665 77

Serial cardiopulmonary variables were recorded over 4 days in 23 children with severe acute respiratory failure. In all patients, pulmonary artery catheters were inserted within 24 hours of the diagnosis of respiratory failure, and all required greater than 10 cm H2O positive end-expiratory pressure to achieve adequate oxygenation. Eight patients died (35% mortality). Evaluation of systemic hemodynamic variables indicated that survivors had higher blood pressures than nonsurvivors, although neither group was in the hypotensive range. Systemic vascular resistance was lower in the nonsurvivors. Cardiac function as evaluated by cardiac index, right ventricular stroke work index, and left ventricular stroke work index was similar in both groups. Survivors demonstrated elevations in mean pulmonary artery pressure and pulmonary vascular resistance during the first 36 hours, with gradual improvement thereafter. In contrast, pulmonary artery pressure and resistance increased progressively in patients who died. Intrapulmonary shunt fractions remained high in the nonsurvivors despite the use of up to 25 cm H2O PEEP. Cardiac function and oxygen delivery were well maintained in both groups despite the high levels of PEEP.
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PMID:Cardiopulmonary abnormalities in severe acute respiratory failure. 670 90

The hemodynamic effect of prostaglandin E1 (PGE1) on acute respiratory failure is investigated. Eight adult mongrel dogs were subjected to oleic acid-induced acute respiratory failure. Four dogs received PGE1 intravenously one hour after oleic acid injection, and four received an equal volume of saline. Cardiac output, arterial PO2 and alveolar-arterial oxygen difference decreased significantly in the saline-treated animals, and systemic vascular resistance increased. These parameters were maintained in the PGE1 group, and stroke volume and arterial-venous oxygen difference were improved. Pulmonary vascular resistance increased in both groups. This beneficial effect of PGE1 in acute respiratory failure may be related to maintenance of hemodynamics and pulmonary gas exchange and to improved tissue oxygenation.
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PMID:The hemodynamic effects of prostaglandin E1 (PGE1) in acute hypoxic respiratory failure. 719 70

Amiodarone therapy has been implicated as a risk factor for cardiothoracic surgical procedures. In patients undergoing map-guided surgical procedures for the treatment of ventricular tachycardia, we compared the perioperative course of those receiving long-term amiodarone therapy (n = 36) versus that in those not receiving the drug (n = 31). The two groups were similar with respect to age, sex, presenting symptoms, functional class, extent of coronary artery disease, presence of a ventricular aneurysm, technique of ventricular tachycardia ablation, cross-clamp or pump time, the number of vessels grafted, the operative fluid balance, and a need for intraaortic balloon pump or inotropic agent support. In 5 patients receiving amiodarone, epinephrine was required to maintain a normal systemic vascular resistance and adequate arterial pressure. Postoperatively, 6 patients (17%) on amiodarone therapy suffered acute respiratory failure. In spite of aggressive therapy, 3 of these patients died. Only 1 patient not receiving amiodarone died of a stroke. We conclude that amiodarone therapy in patients undergoing open heart operations is associated with an increased risk of severe pulmonary complications (p = 0.03 by Fisher's exact test). Amiodarone therapy should be withheld in patients with ventricular tachycardia until they have been assessed as candidates for possible surgical intervention.
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PMID:Are patients receiving amiodarone at increased risk for cardiac operations? 788 40

The short-term haemodynamic effects of terminating dopamine and/or a combination of noradrenaline and nitroglycerin infusions were studied in 21 patients in acute respiratory failure. Patients were studied during treatment and 10 min after infusions were stopped. Off treatment, stroke index and cardiac index decreased significantly from 40.2 to 36.9 ml m-2 (P < 0.02) and from 3.80 to 3.42 litres m-2 (P < 0.02), respectively. Cardiac filling pressures decreased significantly and systemic vascular resistance increased, when infusions were stopped. As to heart rate, mean arterial pressure, mean pulmonary arterial pressure, right and left ventricular ejection fraction there were no significant changes between the data obtained during and off treatment. Although the haemodynamic status was significantly better during treatment with dopamine and/or noradrenaline-nitroglycerin in some respects, the overall beneficial effects of inotropic support were much less than anticipated.
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PMID:The effects of dopamine and noradrenaline on cardiovascular function in patients with acute respiratory failure. 817 29


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