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

Recent studies demonstrated that epinephrine causes significant pulmonary A-V shunting. This study reports the effect of alpha and beta adrenergic blockade on this shunting. Sixty-three anesthetized mongrel dogs were ventilated with a mechanical respirator. Measurements of (1) the pulmonary shunt, (2) cardiac output, (3) mean pulmonary artery, pulmonary capillary wedge and systemic pressures, and (4) pulmonary and systemic vascular resistances were obtained at 5, 15 and 30 minute intervals during the first hour and hourly for 5 hours. Fifteen dogs received no treatment. All others received epinephrine hydrochloride, 2 mug/kg/min for 5 hours. Ten received epinephrine only. Ten were pretreated with propranolol hydrochloride, 250 mug/kg, 12 with phenoxybenzamine, 1 mg/kg, and 16 with phenoxybenzamine and propranolol. Propranolol significantly decreased the epinephrine induced pulmonary shunt at all times and was the most effective drug. Phenoxybenzamine decreased the early shunting, but less than propranolol, and did not decrease the late shunting. Blockade with propranolol and phenoxybenzamine was less effective than propranolol alone. Based on the observed hemodynamic changes it was suggested that beta blockade is effective in reducing epinephrine induced pulmonary insufficiency by favorably altering the flow and distribution of pulmonary blood flow which in turn decreases epinephrine induced ventilation-perfusion inequalities and capillary hypertension both of which result in shunting. Conversely phenoxybenzamine has an unfavorable effect on the pulmonary flow. These studies support previous work in animals and man which showed that beta adrenergic stimulation is important in the pathogenesis of pulmonary insufficiency. Because the amounts of epinephrine used produce blood levels observed in critical illness, these studies add support to a relationship between the increased catecholamine stimulation of critical illness and the associated and often unexplained pulmonary insufficiency.
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PMID:Effect of alpha and beta adrenergic blockade on epinephrine induced pulmonary insufficiency. 0 61

Rupture of the aorta frequently occurs in major blunt trauma to the thorax, but few patients survive long enough to develop a chronic aneurysm. A TDMAC-heparin-coated shunt was used for operative procedures on the thoracic descending aorta in 5 patients aged 18--40 years. The lesions constituted in 4 recent ruptures and 1 chronic aneurysm. In 3 cases the aneurysm was resected and replaced with a prosthetic graft. End-to-end aorta sutures were performed in the other two cases. One patient died of renal and pulmonary insufficiency. There have been no complications attributable the shunt. The advantage of this shunt include elimination of the need for systemic heparin, avoidance of hypertension during crosslamping, and adequate perfusion of the distal circulation without an interposed pump. Because of the ease of handling and low risk we consider the use of this shunt the preferred method for operative procedures on the thoracic descending aorta.
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PMID:[Surgical management of traumatic thoracic aortic aneurysms using the TDMAC-heparin shunt]. 45 84

Setting out from the components of respiratory function, i.e., ventilation, distribution, diffusion, circulation, respiratory mechanics, and regulation of breathing, the pathogenic mechanisms leading to respiratory failure are discussed. In every case, the vital capacity is decreased by 4 factors, namely loss of ventilated lung parenchyma, diminished compliance of lungs, thorax or both, airway obstruction, and insufficient respiratory airflow. With few exceptions, these alterations can be attributed to the two general groups of obstructive and restrictive disturbances of ventilation. Essential for the understanding of airway obstruction from the viewpoint of mechanical ventilation is the dependence of the airway caliber on lung volume, thoracic pressure, and bronchial gas flow. The functional differentiation of restrictive disorders between forms with lung retraction(fibrosis, scarring) and with lung fettering (pleural thickening) is important for adequate correction of complications during the intensive care phase. Respiratory failure is the consequence of these alterations which usually impede pulmonary gas exchange. Hypoxemia results in most situations through disturbance of ventilation/perfusion ratio, especially increase of anatomical or functional pulmonary right-to-left shunting. Disturbance of diffusion or alveolar hypoventilation are far less frequently leading mechanisms for hypoxemia. The differential diagnosis of these hypoxemic mechanisms is generally by arterial blood gas analysis under resting conditions breathing air and 100% oxygen, and during exercise. Respiratory failure often leads to hypertension in the lesser circulation. Pulmonary arterial hypertension must be subdivided into the active, the passive and the hyperdynamic forms, of which only the active component is important for the evaluation of pulmonary insufficiency since only this kind of elevated pressure in the pulmonary circulation is connected with increased vascular resistance due to thoracopulmonary disease. By restoration of normoxic conditions, the functional variant of active pulmonary hypertension can be efficiently improved by correction of respiratory disease or directly by treatment with oxygen and by mechanical ventilation. Finally, disturbances of gas transport in the blood may have an essential bearing on respiratory failure, but are often overlooked in diagnostic and therapeutic considerations. Shifting of the oxygen-dissociation curve to the left may, by increased oxygen affinity of hemoglobin, create a lack of oxygen in the peripheral tissue, while right wardshifting impedes oxygenation of hemoglobin in the lung. Thus, the correction of acidosis and elevated body temperature may become an important factor in the treatment of respiratory failure.
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PMID:[Basis of respiratory insufficiency]. 52 97

The peak systolic pressure ratio PRV/PLV of the right and left ventricle after correction of the outflow tract (OFT) in Tetralogy of Fallot (TF) yields reliable dates about the efficiency of the outflowtract correction and the probability of survival. In 110 patients (2 to 57 years) the ratio after correction PRV/PLV was measured and compared with different methods of reconstruction of the OFT. Infundibulectomy (54) pericard-patch insertion across the pulmonary valve ring (43) and a valve bearing Hancock-Conduit (13) were used. To calculate the statistical differences the U-test according to Wilcoxon, Whitney, Mann was applied on the 95% level. Moreover the pulmonary insufficiency (PI) was evaluated in 60 patients within 15 to 60 days, after correction with a videodensitometric method. There is no PI after use of a valve bearing Hancock-Conduit. In severe TF a valve bearing Hancock-Conduit is hemodynamically superior to a pericard-patchreconstruction of OFT to relief right ventricular hypertension, particularly if hypoplasia of pulmonary vessels and pulmonary vascular disease after shunt-operation is present.
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PMID:[Hemodynamics after reconstruction of the outflow tract in tetralogy of Fallot. Infundibulectomy, patchreconstruction or valve rearing conduit (author's transl)]. 92 67

Between 1979 and 1988, 656 patients were operated upon for abdominal aortic aneurysm. Elective operation was performed in 287 patients (44%) and acute operation in 369 patients. A ruptured aneurysm was found in 218 patients (33%). Patients with arteriosclerotic heart disease, hypertension, impaired renal function or chronic pulmonary disease showed an increased perioperative mortality. Development of postoperative cardiac and renal complications could not be related to previous cardiac or renal diseases. The major postoperative complications were renal failure in 81 patients (12%), pulmonary insufficiency in 77 patients (11%) and cardiac complications in 96 patients (13%). Failure of one or more organs occurred in 153 patients (23%) and the mortality rate for patients with multiorgan failure was 68%. Complications leading to reoperation occurred in 93 patients (14%). The perioperative mortality was 18.8%. The mortality for elective cases was 4.8%, for symptomatic cases 17.2% and 37% for ruptured aneurysms. The five-year survival rate was 48% for ruptured aneurysms, 70% for symptomatic cases and 75% for elective cases. After six months the life expectancy in these three groups of patients were identical and comparable to the expected survival for a sex and age matched control population.
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PMID:Surgery for abdominal aortic aneurysms. A survey of 656 patients. 193 27

A retrospective chart review was conducted of 26 organ donors to determine hemodynamic and metabolic derangements encountered and nursing requirements for donor organ maintenance. There were 15 boys and 11 girls with a mean age 6.57 +/- 5.46 years. Mean donor maintenance time was 10.5 +/- 6.7 hours. Cardiorespiratory derangements included hypotension in 16, hypertension in 6, arrhythmias in 17 (premature ventricular contraction in 4, bradycardia in 8, paroxysmal atrial tachycardia in 3, and ventricular tachycardia in 2), asystolic events in 5, pulmonary insufficiency in 6, anemia in 8, and thrombocytopenia in 8. Metabolic and hormonal derangements included hyperglycemia in 18, hypokalemia in 20, hyperkalemia in 4, hyponatremia in 3, hypernatremia in 17, metabolic acidosis in 10, and diabetes insipidus in 15. Hypothermia (temperature 33.3 degrees +/- 0.4 degrees C, mean +/- SD) occurred in 14 donors. The mean physiologic Stability Index score was 22.2 +/- 4.7 and mean Therapeutic Intervention Score was 46.7 +/- 5.8. Total number of nursing hours spent in donor maintenance was 424.5 hours. Therapies offered included diuretics in 10, sodium bicarbonate in 8, antibiotics in 6, insulin in 12, pitressin in 13, verapamil in 3, isoproterenol in 3, dopamine in 17, and intravenous potassium boluses in 14. Of the potential 26 donors, 46 kidneys, 8 hearts, 14 livers, 3 pancreas, and 9 corneas were retrieved in transplantable condition. With appropriate donor maintenance, organs suitable for transplantation can be retrieved despite significant pathophysiologic derangements. Physicians intending to provide donor support should be comfortable with invasive monitoring and cardiorespiratory support and be prepared to provide a nurse to patient ratio of 2:1 at the bedside.
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PMID:Pediatric organ donor maintenance: pathophysiologic derangements and nursing requirements. 278 Jan 31

This is the case of a 34-year-old woman with Ehlers-Danlos syndrome whose cardiopulmonary manifestations are the following: Prolapse of mitral and tricuspid valves. Aneurysmal dilatation of main arteries without aortic or pulmonary insufficiency. Disturbances in pulmonary function tests and pulmonary arterial hypertension. The diagnosis was verified by skin biopsy and an electron microscopic study. Due to the clinical and histopathological characteristics, we have considered this case to be a non-specified type of the 10 varieties described up to now, and have decided to report it also because of the interesting findings in the hemodynamic and pulmonary function tests.
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PMID:[Cardiovascular abnormalities in Ehlers-Danlos syndrome. Report of a case]. 278 94

Major thermal injury is associated with alterations in both pulmonary and systemic vascular resistance. Pulmonary artery hypertension may lead to right heart dysfunction and pulmonary insufficiency. The effect of thermal injury on vascular reactivity is unknown. Increases in circulating vasoactive substances, as well as alterations in vascular smooth muscle receptor activity, have been hypothesized to occur following thermal injury. We have studied aorta and pulmonary artery vascular sensitivity to five agonists in a 35% full-thickness thermal injury rat model. Vascular reactivity was normal to agonists that constrict vascular smooth muscle via receptor-mediated calcium influx. Unresuscitated and resuscitated burn injury resulted in a decrease in peak tension development to prostaglandin F2 alpha (PGF2 alpha) and potassium, agonists whose effects are mediated via membrane depolarization. Fluid resuscitation synchronous with burning did not alter peak tension development in agonists whose actions were mediated via receptor mechanisms. Peak tension development in resuscitated animals to agonists that affect contraction by depolarization remained deficient. To rule out simple blood loss as the etiology for these changes, the experiment was repeated in rats sustaining an acute 25% blood volume loss. Simple hypovolemia induced no changes in aortic or pulmonary vascular sensitivity. We hypothesize that thermal injury may result in a depolarization of vascular smooth muscle membranes altering voltage-dependent calcium channels.
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PMID:Vascular reactivity following thermal injury. 316 74

Late results were studied in 63 patients who underwent complete repair of tetralogy of Fallot. Mild pulmonary stenosis (PS) was present in 73%, moderate PS in 17% and severe PS in 10% of the patients. When a transannular patch was used, wider enlargement of the pulmonary annulus did not always relate to a decrease in right ventricular pressure and right ventricular to pulmonary artery pressure gradient in the late postoperative period. Pulmonary regurgitation (PR) of grade 2 or less did not relate to the late postoperative hemodynamics and cardiac function. PR of grade 3 or over led to right ventricular and pulmonary artery hypertension, and to increases in right ventricular end-diastolic volume and CTR. PR of grade 4 impaired left ventricular function. PR of grade 3 or over with moderate PS led to elevation in right ventricular end-diastolic pressure. In patients with mild PS and PR of grade 2 or less, late postoperative hemodynamics and cardiac function were excellent. To maintain excellent postoperative hemodynamics and cardiac function, it is imperative to obtain PR of grade 2 or less and to use a procedure which will lead to excellent development of the pulmonary annulus. In conventional procedures using a transannular patch, a CSAI of less than 2.5 cm2/m2 and precise coaptation between the original pulmonary cusp and the cusp mounted on the patch will aid in avoiding significant PR.
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PMID:Postoperative long-term results in total correction of tetralogy of Fallot: with special reference to method and degree of relief of right ventricular outflow tract obstruction. 379 55

We conducted a prospective study of captopril therapy in patients with scleroderma and combined hypertension and renal insufficiency. In all seven patients studied during a 1-year period, control of blood pressure was achieved, and in six of the seven, renal function stabilized or improved. The total daily dosage of captopril ranged from 32 to 100 mg, divided into doses taken every 6 to 8 hours. Although one patient had a suspected captopril-induced rash for a short time, none of the other patients had any adverse side effects. Renal biopsies were performed in six patients; in three of them, specimens were obtained both at the beginning and at the end of the study. The initial biopsy specimens showed changes that were similar to those described in other reports. Findings on repeat biopsies were unchanged except for evidence of chronicity. In the six patients with controlled blood pressure and improved or stabilized renal function, the improvement was maintained for 1 1/2 to nearly 3 years on this drug therapy. Using specific measurements of skin compliance and vascular blood flow in the upper extremities, we could detect no evidence, however, of concomitant improvement in these other features of the disease. Although the blood pressure was controlled with captopril, one patient had progressive skin induration, one had progressive pulmonary insufficiency, and another had progressive renal failure.
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PMID:Use of captopril as early therapy for renal scleroderma: a prospective study. 390 66


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