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

Leukotriene D4, a constituent of slow-reacting substance of anaphylaxis, elicits a pressor response followed by hypotensive shock in spontaneously hypertensive rats but not in other rats. Hemodynamic mechanisms underlying this pattern in spontaneously hypertensive rats, pithed and vagotomized to eliminate circulatory reflexes, were studied using radiolabeled microspheres. One minute after leukotriene D4 administration (20 micrograms/kg i.v.), mean arterial pressure increased by 54 mm Hg, total peripheral resistance index increased by 68%, heart rate decreased by 34 beats/minute, and cardiac index was unchanged. Profound reductions of blood flow and increases of vascular resistance in the hepatosplanchnic area, skeletal muscles, and skin also occurred. Five minutes later, mean arterial pressure remained elevated (+35%), hematocrit rose (+17%), and total peripheral resistance index increased, which offset 40% decreases in cardiac and stroke volume indices. Ten minutes after leukotriene D4 administration, during hypotension, cardiac and stroke volume indices and blood flow to all vascular beds declined further while total peripheral resistance index and hematocrit (+28%) continued to rise. In Wistar-Kyoto rats, administration of leukotriene D4 caused less of a pressor response (+34 mm Hg) because vascular resistance was increased only in skeletal muscles, which was followed by a slight hypotension without any significant changes in cardiac and stroke volume indices, total or regional vascular resistance, and hematocrit. Thus, in spontaneously hypertensive rats the leukotriene D4-induced pressor response appears to be caused by generalized vasoconstriction, and the subsequent hypotension appears to result not from vascular collapse but from reduced cardiac output.
Hypertension
PMID:Overall and regional hemodynamic effects of leukotriene D4 in spontaneously hypertensive rats. 400 88

Obesity is an additional risk factor in surgical patients. The mortality rate in obese patients is high (3.6% in my series) and the morbidity is much higher. These patients may be prediabetic, diabetic, hypertensive or atherosclerotic and they are liable to develop postoperative coronary thromboses and chest complications such as acute massive collapse of the lung or bronchopneumonia. In upper abdominal operations, they are more liable to develop septic wounds and postoperative distension. Thrombo-embolic phenomena are more pronte to develop in the obese. Intraoperative bleeding is particularly frequent in obese patients with hypertension, atheroscleroses and fatty liver. Surgery in severe obesity should be limited to emergencies. Elective surgery is not recommended unless it is mandatory, e.g. to reduce weight in hard-core obesity which resists expert medical treatment. Many hard-core obesity cases have psychological problems and require special pre- and postoperative psychological care.
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PMID:The hazards of surgery in the obese. 405 70

Anaphylactoid reactions were evoked during intravenous induction of anaesthesia in two patients on three occasions. In the first patient the reaction occurred during the first anaesthetic on propranolol and hydrochlorthiazide medication due to hypertension. Since the major target organ for the anaphylactoid reaction in this patient was the pulmonary circulation, the cardiovascular collapse at his first anaesthetic was misinterpreted as a nonspecific reaction to anaesthesia reinforced by the beta-receptor blocking therapy. At the second anaesthetic central haemodynamics, plasma adrenaline (A) and noradrenaline (NA) were measured. Following injection of thiopentone sudden decreases of mean arterial blood pressure (60%), cardiac output (60%), and systemic vascular resistance (20%) were observed. Thirty minutes later, still during circulatory shock, the concentration of A had increased whereas that of NA was normal. In the second patient the anaphylactogenic drug was supposed to be thiopentone, suxamethonium or alcuronium. In this patient, the fall in arterial blood pressure was associated with bronchospasm and the sudden appearance of peripheral oedema. In both cases initial resuscitation comprised volume replacement and beta 1-agonist therapy but the cardiovascular state was not normalized until vasoconstricting agents were infused.
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PMID:Successful vasoconstrictor therapy of anaphylactoid reactions during induction of anaesthesia. A report of two cases. 406 Oct 10

In peripheric arteriopathies, alterations occur to the venous system with a particular swelling of the veins of the foot-top, in the subjects (sclerotic or diabetic) at the 2nd and 3rd Fontaine stage, which gradually decreases until the collapse in the most advanced levels of the arterious affection (4th stage). In order to verify all that, we examined 40 artheriopathic subjects at the different Fontaine stages through a c.w. doppler apparatus and an impedence plethysmograph. Together with the modification of the arterious doppler velocitogram and the reduction of the Winsor index, we noticed that the velocity of the venous flow increases together with a venous hypertension that reaching the highest values at the 3rd stage, while at the 4th stage they are reduced because of the progress of the sclerosis. The impedence plethysmogram shows a reduction of the systodiastolic sphygmic excursion with a variation of the basic line, depending on the respiration, proportional at the clinic stage. In diabetic subjects the progress of the disease is more precocious because of the quicker implication of the microcirculation.
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PMID:Instrumental evaluation of the venous circulation in the arteriopathic subjects. 406 61

1. The reductions in arterial pressure and preganglionic sympathetic activity evoked by aortic nerve stimulation in the rabbit were studied before and during administration of constant inspired concentrations of the inhalation anaesthetics cyclopropane, halothane, and ether. The background anaesthetic was pentobarbitone, gallamine triethiodide was given, and pulmonary ventilation was with 100% oxygen.2. During light pentobarbitone anaesthesia, aortic nerve stimulation usually induced similar reductions in arterial pressure and preganglionic discharge, expressed as the maximum percentage reduction from prestimulation levels. There were two components in the sympathetic responses, attributable to A and C fibre excitation in the aortic nerve, which was also shown to contain a third fibre group with properties similar to those of B fibres.3. The arterial pressure, heart rate, and preganglionic sympathetic responses to aortic nerve stimulation were rapidly and profoundly inhibited by 50% cyclopropane, which also produced arterial hypertension.4. Halothane (3%) significantly inhibited the depressor responses, but even in the presence of severe hypotension the arterial pressure could usually be further reduced by aortic nerve stimulation. The inhibitory effects of 2% halothane were slow in onset and not pronounced. In the concentrations used, these actions of halothane were significantly less than those of cyclopropane.5. The inhibitory effects of ether on the depressor responses were roughly intermediate between those of cyclopropane and halothane; complete suppression of the responses occurred with high ether concentrations, which were also liable to cause circulatory collapse.6. It is concluded that the three anaesthetics significantly inhibit impulse transmission through central baroreceptor pathways; the implications of the findings are discussed in relation to the different circulatory actions of these anaesthetics.
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PMID:The effects of cyclopropane, halothane and ether on central baroreceptor pathways. 596 32

The inhalation of toxic gases or vapours is capable of resulting in pulmonary oedema (P.O.), the mechanism of which corresponds, on the basis of a number of hemodynamic studies carried out, to that which characterises the so-called "lesional" pulmonary oedema, which is different from so-called "hemodynamic" oedema. Classically PAP, PCP and P wedge pressure have virtually normal values (normalisation of pulmonary arterial hypertension by correction of hypoxemia). CI and SWILV are normal or increased and pulmonary resistances are virtually normal. The origin of the oedema is thus related to an increase in alveolo-capillary permeability. The inhalation of toxic gases or vapours with a caustic or irritant action, or containing particles, however, usually adds on an obstructive syndrome, similar to a severe asthmatic attack. Under such conditions, the marked reduction in intrathoracic pressure during inspiration definitely favours pulmonary oedema by decreasing intra-alveolar pressure and by the accumulation of blood in the pulmonary circulation, and is capable of masking pulmonary arterial hypertension. Raised pressure, related to expiratory effort, on the contrary, decreases venous return and may result in collapse of the capillaries. Whilst the principal mechanism of PO by the inhalation of toxic gases or vapours is related to an increase in alveolo-capillary permeability, it is nevertheless important not to under-estimate the role of variations in intra-thoracic pressures which may constitute a provoking or at least aggravating element.
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PMID:[Pulmonary edema of toxic origin. Hemodynamic data]. 611 Dec 79

In a series of 40 patients with severe head injury (L.C.S. less than or equal to 12), we simultaneously studied the variations of intracranial pressure (I.C.P.) and cerebrospinal fluid (C.S.F.) spaces (ventricular and subarachnoidal) on C.T.-scan. At the time of C.T.-scan, normal C.S.F. spaces mean a normal I.C.P. (less than 15 torr) but cannot preclude a secondary intracranial hypertension. With a collapse of the C.S.F. spaces, it is to be geared that a severe hypertension occurs (greater than 40 torr).
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PMID:[Intracranial pressure in severe brain injuries. 1st Part: X-ray computed tomography of cerebrospinal fluids and manometry]. 633 25

Fibrillary renal deposits and nephritis. The authors have studied 8 patients whose glomeruli contain abundant fibrils in their mesangial matrix and basement membranes. Although the location of these fibrils is very similar to that of amyloid, they are about twice the size of amyloid fibrils, averaging 20 nm in width, and fail to react as amyloid does with special stains. Immunofluorescence-microscopic studies are usually positive with antiserums to IgG, often IgM, and in some cases IgA, and also kappa and lambda light chains, C3, and C4. The fibrils are associated with diffuse mesangial widening and increased mesangial matrix strands. Although peripheral glomerular capillary walls appear to be spared initially, their eventual involvement leads to glomerular capillary collapse and glomerular obsolescence. Crescent formation occurred in 5 cases, focally in 3 and diffusely in 2. Tubular basement membrane involvement was seen in 1 case. These patients exhibit hematuria, and proteinuria, and often hypertension and renal insufficiency. Proteinuria was in the nephrotic range in 3 patients in whom involvement of glomerular capillary basement membranes was extensive. Unless electron microscopy is applied to renal biopsies, these cases may be considered to represent mesangiocapillary or rapidly progressive glomerulonephritis, or amyloidosis. The nature of these fibrils is as yet not determined. It is likely that they have been called "atypical amyloidosis" in the past.
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PMID:Fibrillary renal deposits and nephritis. 635 91

Sixty-seven bronchoscopic examinations were performed in a busy surgical intensive care unit on 51 patients, and the techniques, morbidity, and outcome were prospectively analyzed to assess the efficacy and safety of the procedure in this particular patient population. General surgical trauma, cardiothoracic, and orthopedic patients were included. Fifty-three (79%) procedures were performed with the flexible instrument, while 14 patients (21%) underwent rigid endoscopy. Forty-six patients were being mechanically ventilated; 30 had endotracheal tubes, and 16 had tracheostomies. Suspected lobar collapse (60%), persistent pulmonary infiltrates (3%), suspected aspiration (21%), and suspicion of airway trauma (12%) were the primary clinical indications for bronchoscopy. No deaths occurred. Complications were seen in 16 per cent of the procedures and 17 per cent of the patients. There were arrhythmias (other than sinus tachycardia) in seven procedures (11%) and one episode each of hypertension, self-limited endobronchial bleeding, mediastinal emphysema, and increased intracranial pressure. Significant improvement was demonstrated for patients with lobar collapse but not for those with mild atelectasis or pulmonary infiltrates on radiographs taken within 24 hours. Overall, 39 patients (58%) improved radiographically, while 38 patients (42%) did not. Differences in arterial PO2 measured before and after bronchoscopy between groups ventilated with an FiO2 of 1.0, and those who were not did not achieve statistical significance (P less than 0.05).
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PMID:Bronchoscopy in the critically ill surgical patient. 646 91

A case of acute intestinal vascular necrosis in a 19-year-old user of oral contraceptives (OCs) is described, and hypotheses explaining the digestive complications of synthetic estrogens are reviewed. The patient had originally presented with a violent gastric pain that subsequently spread to the entire abdomen. An abrupt worsening of her condition involved cardiovascular collapse associated with a peritoneal syndrome, vomiting and dehydration, and hyperleukocytosis. Emergency opening of the peritoneum was followed by evacuation of a large quantity of fetid gas and alimentary debris, and observation of a completely necrosed stomach. A careful lavage of the entire intestinal cavity led to temporary improvement, but it became clear during an attempt at gastrectomy that further treatment would be unavailing and the patient died shortly thereafter. Estrogens were believed to be responsible for the digestive necrosis because it occurred in a young woman who had used an estrogen-rich OC for 3 years and who smoked; a hapatic biopsy confirmed the diagnosis. No traces of other risk factors such as hypertension, hyperlipidemia, diabetes, neoplasia, or obesity were observed. Recent publications indicate that OCs are responsible for a certain number of digestive problems, which may include acceleration of intestinal transit, severe diarrhea, rectorrhagia, ischemic or ulcerative colitis, intestinal infarct which is usually localized, and hepatocellular problems ranging from moderate hepatic insufficiency to malignant tumor and Budd-Chiari syndrome. OCs do not modify hemodynamic regimes, but they may cause elevation of fibrinogen and thrombin, diminution of antithrombin III acitivty, increased platelet adhesivity, and decreased fibrinolysis leading to hypercoagulability. These modifications in hemostasis occur in all OC users and are not statistically correlated with occurence of thrombotic accidents. OCs are probably responsible for parietal vascular lesions; experimental injection of synthetic estrogens is associated with both arterial and venous lesions. The most characteristic anomaly is at the level of the intima, with proliferation of smooth muscle cells and increased conjunctive tissue fibers associated with proliferation of the media or the endothelium. The absence of lipid deposits, the simultaneous appearance of arterial and venous lesions, and other evidence argues against and atheromatous origin of parietal lesions. A significant correlation has been found between high levels of anti-synthetic ethinyl estradiol antibodies and the presence of vascular lesions. It is hypothesized that these circulating immune complexes penetrate the vascular walls of OC users and produce lesions, which may depend on factors such as smoking.
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PMID:[Digestive complications of oral contraceptives: a case of extensive digestive necrosis in a young woman]. 647 54


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