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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Because pulmonary hypertension and systemic hypertension occur during sleep-induced obstructive apnea, six patients underwent overnight hemodynamic monitoring before and after tracheostomy. Variables studied included heart rate, pulmonary artery pressure, femoral artery pressure, and arterial oxygen tension (Po2). After tracheostomy, significant reductions were noted during sleep in mean pulmonary artery pressure from 45 +/- 6 mm Hg (mean +/- SEM) to 22 +/- 2 mm Hg (P less than 0.05) and in mean femoral artery pressure from 137 +/- 6 mm Hg to 97 +/- 3 mm Hg (P less than 0.005). There was also a significant increase for the group in arterial Po2 recorded during the apneic episodes from 38 +/- 3 mm Hg before tracheostomy to 71 +/- 2 mm Hg (P less than 0.001) after tracheostomy. We conclude that tracheostomy improves the hemodynamic abnormalities and hypoxemia that occur during sleep in patients with sleep-induced obstructive apnea.
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PMID:Tracheostomy and hemodynamic changes in sleep-inducing apnea. 69 23

A comprehensive analysis of cerebral hemodynamics and metabolism was carried out in 14 patients with pseudotumor cerebri. Tracer techniques were employed to measure cerebral blood flow (CBF) and vascular reactivity to acute changes in arterial carbon dioxide tension and blood pressure, cerebral blood volume (CBV), and the cerebral metabolic rate for oxygen and glucose. There was a small reduction (p less than 0.01) in CBF (44 +/- 7 ml/100 gm/min; normal, 54 +/- 9) with normal vascular reactivity; an increase (p less than 0.005) in CBV (4.8 +/- 0.8 ml/100 gm; normal, 3.6 +/- 0.5), and normal cerebral metabolism. We conclude that an abnormality of the cerebral microvasculature is responsible for an elevation in CBV, but the intracranial hypertension can be explained only by tissue swelling due to an increase in water content. The relationship between the vascular abnormality and the tissue swelling remains to be defined.
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PMID:Cerebral hemodynamics and metabolism in pseudotumor cerebri. 70 80

Experiences with the anaesthetic management of 248 patients undergoing total hip replacement are presented. Blood loss does not appear to be influenced by hypertension, the method of venting or the type of anaesthetic, with the exception of neurolept-analgesia. The importance of oxygen therapy in the treatment of the pulmonary embolic syndrome is stressed and the prevention of deep venous thrombosis is discussed. Mortality and morbidity figures are given.
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PMID:Clinical considerations in anaesthesia for hip arthroplasty. 71 19

Exercise testing has a definite role in pediatrics today. Different methods are presented, and the value of maximal exercise with determination of oxygen uptake and blood lactate is stressed. In children with heart disease, exercise testing with precordial electrocardiogram can be of both diagnostic and prognostic value. The cardiovascular function at different intensities of exercise is evaluated, serious dysrhythmias may be revealed, hypertension judged and the effect of drug therapy can be checked by exercise testing. It is an important way in assessing the child's functional capacity after heart surgery in the decision whether she or he should take part in physical education and sports activities and in the choice of profession. It is also of great psychological value to the parents and the patient himself. In children with other chronic diseases, e.g., diabetes, obesity, asthma, neurocirculatory dysfunctions--physical training together with exercise testing is of importance for therapy and rehabilitation.
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PMID:Exercise testing in children. 72 65

The respiratory stimulant doxapram hydrochloride has long been shunned in the United States because of a perpetuated fear of the alleged side effects of hypertension and tachycardia with attendant hypermetabolism and increased oxygen consumption. This study reports the results of the administration of doxapram alone, and of doxapram in conjunction with the beta-blocker propranolol on the blood pressure, heart rate, and respiratory rate of 12 healthy unanesthetized volunteer subjects. Results showed an augmentation in blood pressure (especially diastolic), a significant decrease in heart rate, and an unexpected actual increase in respiratory rate in the doxapram/propranolol group. Subtleties of sympathetic balance, as well as proposed future studies are discussed.
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PMID:Modification of cardiopressor and respirogenic effects of doxapram by propranolol. 74 7

Since sub-endocardial ischemia is the consequence of a discrepancy between the blood demand and supply of oxygen at this level, the study of the myocardial performance by the measurement of the endocardial viability ratio (E.V.R.) is both useful and possible during anesthesia. E.V.R. is the ratio between the oxygen supply and demand of the myocardium. It is equal to the diastolic pressure time index (D.P.T.I.) over the tension time index (T.T.I.). Measurements are made at different times, by means of the arterial pressure and the left atrial pressure, as well as with the Datascope-E.V.R. Computer. During gradual morphine administration (0.5-1-1.5 mg/kg) and if no major surgical stress occurs, E.V.R. remains excellent and stable (1.46 - 1.48 - 1.43). It deteriorates more or less (1.29 - 1.09) during tachycardia or hypertension. Within the hour following the end of extracorporeal circulation, E.V.R. significantly improves (1.04 - 1.06 - 1.09 - 1.23). Although E.V.R. measurement is easy during cardiac surgery, it is impossible to carry out in case of arrhythmia. While morphine anesthesia induces no variation in E.V.R., tachycardia or hypertension require the addition of therapeutic drug. Within one hour following the end of extra-corporeal circulation, E.V.R. measurement shows improved endocardial viability, although the hemodynamic parameters undergo no significant change.
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PMID:Measurement of endocardial viability ratio (E.V.R.) during anesthesia for cardiac surgery. 75 39

The literature dealing with radiation myelopathy is reviewed. The following points are to be noticed:radiation myelopathy is a rare complication in the radiation therapy of extraspinal tumors, nevertheless the number of case reports is increasing during the last years; probably this is due to the increasing use of high energy therapy. Already a cord dose of 1000 rad may be dangerous; with an increasing dose the risk of radiation myelopathy is increasing too. Besides the total dose the incidence of radiation myelopathy depends on the rate of delivery, the over-all time of administration, the size of the individual fraction, the field size, the size of the volume irradiated, the type of irradiation, the use of hyperbaric oxygen and some other special conditions of radiation. But the incidence of radiation myelopathy depends not only on radiation technique but also on patients' variables. Individual variations in radiosensitivity are a well known fact; this may be partly due to an inherent biologic variation of response. Moreover the incidence of radiation myelopathy may be intensified by simultaneously existing diseases - above all by hypertension- and probably by some medicaments taken simultaneously. A dependence from age, sex, and the kind of the primary tumor seems not to exist. Radiation lesions of the cervical spinal cord have been reported much more frequently than lesions of the dorsal spinal cord; lesions of the lumbal spinal cord are a very rare event. There exist different conceptions of the pathogenesis: opinions differ as to whether the effect is primarily on the connective tissue and blood vessels or on nerve cells and their axons or if the different tissues are injured simultaneously; moreover an autoimmuno-hypothesis is discussed. The clinical signs of radiation myelopathy can be grouped into two major syndromes: the transient radiation myelopathy and the delayed or chronic radiation myelopathy, which usually develops gradually with a subsequent chronic progressive course but in some cases may occur acutely after the latent period; the course is not always progressive but may be undulating and remissions have been reported in some rare cases...
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PMID:[Radiation injury of the spinal cord]. 77 Feb 97

The relationship of cerebral blood volume (CBV) to cerebral perfusion pressure (CPP), cerebral blood flow (CBF), and the cerebral metabolic rate for oxygen (CMRO2) was examined in rhesus monkeys. In vivo tracer methods employing radioactive oxygen-15 were used to measure CBV, CBF, and CMRO2. Cerebral perfusion pressure was decreased by raising the intracranial pressure (ICP) by infusion of artificial cerebrospinal fluid (CSF) into the cisterna magna. The production of progressive intracranial hypertension to an ICP of 70 torr (CPP of 40 torr) caused a rise in CBV accompanied by a steady CBF. With a further increase in ICP to 94 torr, CBV remained elevated without change while CBF declined significantly. Cerebral metabolic rate for oxygen did not change significantly during intracranial hypertension. For comparison, CPP was lowered by reducing mean arterial blood pressure in a second group of monkeys. Only CBF was measured in this group. In this second group of animals, the lower limit of CBF autoregulation was reached at a higher CPP (CPP approximately to 80 torr) than when an increase in ICP was employed (CPP approximately to 30 torr).
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PMID:Effects of increased intracranial pressure on cerebral blood volume, blood flow, and oxygen utilization in monkeys. 80 93

Autoregulation of cerebral blood flow (CBF) was studied by the arteriovenous oxygen difference method in 13 patients with untreated or ineffectively treated severe hypertension, nine patients with effectively treated, formerly severe hypertension, and ten normotensive controls. Resting mean blood pressure in these three groups was 145 +/- 17 (1 SD) mm Hg, 116 +/- 18 mm Hg, and 98 +/- 10 mm Hg, respectively. Blood pressure was decreased by trimethaphan infusion combined with head-up tilt. The lower limit of CBF autoregulation in the three groups was 113 +/- 17 mm Hg, 96 +/- 17 mm Hg, and 73 +/- 9 mm Hg, and the lowest tolerated blood pressure where mild symptoms of brain hypoperfusion were encountered was 65 +/- 10 mm Hg, 53 +/- 18 mm Hg, and 43 +/- 8 mm Hg. These pressures were all significantly higher (P less than 0.01) in the group of untreated or ineffectively treated hypertensive patients than in the normotensive group demonstrating a shift of CBF autoregulation in the former. The observations in effectively treated hypertensive patients strongly suggested a readaptation of CBF autoregulation toward normal in some cases. In four hypertensive patients studied twice it was found that 8-12 months of antihypertensive treatment on average did not influence the lower limit of CBF autoregulation.
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PMID:Autoregulation of cerebral blood flow in hypertensive patients. The modifying influence of prolonged antihypertensive treatment on the tolerance to acute, drug-induced hypotension. 81 61

The acute hemodynamic effects of 50 mg. of the alpha- and beta-receptor blocking agent AH 5158, administered intravenously, on the systemic and pulmonary circulation were studied in 13 hypertensive patients at rest in the supine and erect positions, and during exercise, with right heart and brachial artery catheterization. AH 5158 induced a significant fall of systemic blooc pressures under all conditions, whereas the pulmonary systolic and mean pressures were lower at rest and unaltered during exercise. The left ventricular filling pressure largely remained unchanged. Blood pressure was lowered predominantly by a reduction in systemic vascular resistance together with a reduction in cardiac output. These effects were particularly pronounced in the erect position and during exercise. Cardiac output was lowered solely by the reduction of heart rate; stroke volume was unchanged or even increased. The arterial-mixed venous oxygen difference increased in the erect position and during exercise. The pattern of AH 5158-induced hemodynamic adaptation comprising a reduction of both vascular resistance and cardiac output, without evidence of significant negative inotropic action, offers a novel basis for treating hypertension with a single drug. Its pharmacological and hemodynamic profile suggests considerable potential in the treatment of hypertensive patients.
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PMID:Acute hemodynamic effects of an alpha- and beta-receptor blocking agent (AH 5158) on the systemic and pulmonary circulation at rest and during exercise in hypertensive patients. 85 Oct 58


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