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Biomedical subjects

B Reichart

Publications and source records attributed to B Reichart.

At least 325 records · Page 18Linked to original sources
PubMed1987

Pathophysiology of pulmonary edema following experimental brain death in the chacma baboon.

Systemic and pulmonary hemodynamics have been studied during the induction of brain death in the chacma baboon. In 11 animals brain death was induced by acute intracranial hypertension. Continuous recording of blood flow through both the pulmonary artery and the aorta was obtained by electromagnetic flow meters placed around these vessels. Mean arterial, central venous, pulmonary arterial, and left atrial pressures were recorded continuously. Systemic and pulmonary vascular resistances were calculated. During the agonal period marked sympathetic activity occurred, with significant increases in circulating catecholamines and systemic vascular resistance. The great increase in systemic resistance resulted in acute left ventricular failure. Mean left atrial or pulmonary capillary wedge pressure rose above the mean pulmonary arterial pressure in 9 animals. As the systemic vascular resistance rose, a significant difference between pulmonary artery and aortic blood flows occurred, leading to blood pooling within the lungs. A mean of 72% of the total blood volume of the animal accumulated within these organs. The increase of left atrial pressure to levels higher than pulmonary artery pressure indicated a state of pulmonary capillary blood flow arrest. This, associated with the blood pooling within the lungs, almost certainly resulted in disruption of the anatomic integrity of the pulmonary capillaries (blast injury); 4 animals developed pulmonary edema, with alveolar septal interstitial hemorrhage.

Animals↗
PubMed1987

Particularities of dual chamber pacemaker therapy in patients after orthotopic heart transplantation.

Since August 1981, 33 orthotopic heart transplantations were performed in our hospital. Three of these patients (9%) had sinus bradycardias with rates as low as 30 beats/min; they were treated by implantation of a dual chamber pacemaker. These patients had two atria as a result of orthotopic heart transplantation, but only the donor atrium was suitable for positioning the atrial lead. In the postoperative period, some nonsurgical complications were observed in one patient who developed atrial fibrillation which we treated with drugs. A cyclosporin-evoked tremor produced several asystoles due to false inhibition by myopotential interference in the VVI mode. During an episode of acute rejection combined with renal insufficiency, loss of atrial and ventricular sensing occurred. The other patients showed no pacemaker-related complications. Our findings in this unique population of pacemaker patients are discussed.

Adult↗
PubMed1987

Hemodynamic and metabolic responses to hormonal therapy in brain-dead potential organ donors.

An evaluation of the beneficial effects of hormonal therapy, consisting of T3 2 micrograms, cortisol 100 mg, and insulin 20 units, administered at hourly intervals intravenously, was assessed in brain-dead patients referred for organ donation. Twenty-six conventionally treated donors (group A) showed a progressive hemodynamic deterioration requiring significant increments of inotropic support in order to maintain cardiovascular stability, necessitating a significant increase in bicarbonate requirements in order to maintain a normal acid-base balance. Of this group, 20% of the donors were considered unsuitable as cardiac donors due to progressive cardiovascular deterioration or sudden ventricular fibrillation. Hormonal therapy was administered to 21 donors (group B) resulting in a significant improvement of cardiovascular status, requiring less inotropic support and significantly less bicarbonate. A significant reduction of serum lactate-pyruvate followed the initiation of the hormonal therapy. In group B, organs from all donors (heart, heart and lungs, and kidneys) were suitable for transplantation, with excellent organ function following implantation of the graft.

Acid-Base Equilibrium↗
PubMed1987

The feasibility of closed mitral valvotomy in pregnancy.

Rheumatic mitral valve stenosis is an important nonobstetric complication of pregnancy in an African country. Between January 1965 and September 1985 41 closed mitral valvotomies with a Tubbs dilator were performed in 39 pregnant women (two first trimester, 22 second trimester, and 17 third trimester). All patients experienced symptomatic improvement from New York Heart Association Class 3.01 (average) preoperatively to 1.22 postoperatively. There were no deaths related to the operation and delivery. Fetal deaths were due to postoperative spontaneous abortion in two cases (4.9%) or premature labour in three cases (7.3%), for an overall survival of 36 babies (87.8%). Fetal morbidity was due to prematurity or dismaturity in three infants, all of whom survived. Thirty-three normal infants were delivered at term. Nine patients needed subsequent surgical procedures for mitral valve restenosis 5 to 17 years (mean 10.2 years) after the initial closed valvotomy: Repeat closed valvotomy was performed in three patients after 5, 8, and 10 years (the first two during subsequent pregnancies), an open procedure was performed in one after 6 years, and five patients underwent subsequent mitral valve replacement after 11 (two), 12 (two), and 17 (one) years. Two late deaths occurred; one after 10 years, as a result of pneumonia and meningitis, and the other after 12 years, before a mitral valve replacement for restenosis could be performed. None of the remaining patients has required further surgical procedures, but two have moderate symptoms. Closed mitral valvotomy gives satisfactory results in pregnant patients with severe mitral stenosis. When indicated during pregnancy, it should be performed at any stage of the pregnancy.

Adolescent↗
PubMed1986

Interpretation of endomyocardial biopsy after heart transplantation. Potentially confusing factors.

Histological examination of the myocardium by endomyocardial biopsy is a standard method of monitoring the presence of acute rejection in the transplanted heart. The histopathological consequences of the biopsy procedure itself have been investigated in non-transplanted hearts in the baboon. Organization of thrombus, necrosis of myocytes adjacent to the biopsy site, and mononuclear cells (including T lymphocytes) surrounding the biopsy site appear after biopsy; should a subsequent biopsy be taken from this area, these appearances may be confused with the appearances associated with acute or resolving cardiac rejection. This problem has been encountered in the clinical transplant programme. Observations on the myocardial histopathological changes resulting from brain death and from parasitic infestation, both of which may also lead to confusion in the interpretation of endomyocardial biopsies, are also presented. Awareness of these factors in patients with heart transplants should lead to caution in the interpretation of the histopathological features and may avoid unnecessary extra immunosuppression early after transplantation. Observations indicate that endomyocardial biopsy should not be the sole method of monitoring for the development of acute rejection.

Animals↗
PubMed1986

False aneurysm of the descending thoracic aorta caused by an inhaled foreign body. A case report.

A case of traumatic false aneurysm of the descending thoracic aorta is reported. The aneurysm was caused by the inhalation of a needle into the left main bronchus. The diagnosis of a false aneurysm was made 42 days after inhalation. The aneurysm was repaired by direct suture without the need for circulatory assistance or a shunt. There were no intra- or postoperative complications.

Adolescent↗
PubMed1986

Surgery in patients with heart transplants. Anaesthetic and operative considerations.

As cardiac transplantation becomes more common, so an increasing number of patients with functioning heart transplants may require surgery for related or unrelated non-cardiac conditions. Fifteen patients who have undergone a total of 39 operations (excluding retransplantation) since heart transplantation were reviewed; 36% were for infective conditions and 23% each for gastro-intestinal and vascular lesions. There was one postoperative death in a patient undergoing leg amputation for overwhelming Clostridium welchii infection. There were no major non-fatal complications. The conditions for which operation may be necessary, the specific problems of anaesthesia and surgery in such patients, and the prophylactic measures which may be undertaken to ensure an uncomplicated clinical course are discussed. A clear understanding of the physiology and pharmacology of the denervated heart is essential if these patients are successfully to undergo major operations requiring general anaesthesia.

Adolescent↗
PubMed1986

[Improved regional myocardial function after aortocoronary bypass surgery noninvasive studies using the first-pass technic].

50 patients after coronary artery bypass grafting were matched with 50 not-operated patients. After a follow-up period of four years they were investigated by first pass radionuclide angiography. Revascularized myocardial areas showed significantly higher regional ejection fraction during exercise and in territories with prior myocardial infarction. The results proved the hemodynamic benefits of coronary artery bypass grafting even in territories with poor myocardial function.

Angina Pectoris↗
PubMed1986

A new model for hetero-orthotopic heart-lung transplantation in the dog.

A method of hetero-orthotopic heart-lung transplantation is described in the dog. The model was developed to study patterns of rejection in the transplanted heart and lung, since the dog will not survive bilateral pneumonectomy and loss of the Hering-Breuer reflex. After removal of the recipient's left lung the donor heart and left lung are explanted en bloc. End-to-end connection is made of both left main bronchi, and the donor aorta is joined end-to-side with the recipient's descending aorta. An atrio-atrial anastomosis is performed between the recipient's left and the donor's right atrium. Four experiments were done to develop the surgical technique and 10 long-term studies were performed to investigate rejection patterns. The average survival rate of these animals was 28.5 +/- 8.3 days, ranging from 5 to 53 days. Causes of death were not due to operative complications. Heterotopic heart-lung transplantation is an uncomplicated surgical method which does not require cardiopulmonary bypass or anticoagulation and allows the investigator to study heart and lung grafts in dogs for long-term periods after surgery. Bronchoscopy, bronchoalveolar lavage, and heart and lung biopsies of both donor and recipient organs can be performed.

Animals↗
PubMed1986

Acute isolated pulmonary rejection following transplantation of the heart and both lungs: experimental and clinical observations.

Early observations following transplantation of the heart and both lungs have suggested that acute rejection occurs simultaneously in both organs. Endomyocardial biopsy could, therefore, be used to monitor rejection in both heart and lungs. We present here our experience with heart-lung transplantation in the baboon, and in two recently observed human patients. The evidence we provide suggests that acute rejection may occur earlier in the lungs than in the heart, and that monitoring the heart alone may prove inadequate. Of 12 baboons that survived heart and lung transplantation, 11 died from acute isolated pulmonary rejection; 10 of these 11 animals showed no features of cardiac rejection. In 2 of 6 human patients who have undergone this operation, an episode of acute pulmonary rejection is believed to have occurred in the absence of cardiac rejection. There is no easy method of confirming pulmonary rejection directly (other than open-lung biopsy, which is clearly contraindicated as a routine procedure). We suggest that more attention be directed toward developing tests that indicate acute rejection but are not organ specific, rather than relying on techniques that diagnose cardiac rejection only.

Acute Disease↗
PubMed1986

Prevention of myocardial injury during brain death by total cardiac sympathectomy in the Chacma baboon.

In a previous study, structural myocardial damage was found to occur in 60% of baboons after brain death had been induced by a rapid increase in intracranial pressure. In the present study, we attempt to clarify the causative mechanisms involved in the development of such injury. Three groups of baboons were subjected to brain death: group A, the control; group B, those with previous surgical or pharmacological cardiac sympathectomy or cardiac denervation; and group C, those with bilateral vagotomy, incomplete sympathectomy, or bilateral adrenalectomy. Electrocardiographic and hemodynamic responses to brain death were greatly modified in group B baboons compared with responses in groups A and C. Groups A and C showed a high incidence of myocardial necrosis, whereas no myocyte damage was seen in the hearts of group B baboons. The histological appearance of innervated hearts following brain death (groups A and C) may closely resemble that seen during an acute rejection episode following cardiac transplantation. We suggest that myocardial damage occurring during the process of dying may be related to endogenous catecholamine release (possibly resulting in increased calcium uptake by the myocardial cells), inducing various forms of myocyte necrosis. This may result in early failure in a donor heart following cardiac transplantation.

Animals↗
PubMed1986

Surgical treatment of aneurysms of the ascending aorta. Twelve years' experience in 66 patients.

This study presents the results in 66 patients undergoing surgery for concomitant supracoronary vascular interposition and valve replacement carried out at the Department of Cardiac Surgery of the University of Munich, West-Germany, over a period of 12 years (from July 1, 1973 to June 30, 1985) using a technique similar to that described by Wheat. Forty-seven percent of the cases were true aneurysms and 20% chronic dissections. Thirty-three percent of patients had acute dissections. Early mortality was 16% in the total patient population, 9% in the group having true aneurysm and 32% in the group having acute dissection. No early death was observed in association with chronic dissections. The actuarial one-year survival rate in patients with true aneurysm or chronic dissection was 83.6%, and 54.1% in patients with acute dissection. The corresponding 4-year survival rates were 76.4% and 54.1%, respectively. The average improvement according to the New York Heart Association classification was 1.5 grades. These results confirm that the operative approach to ascending aortic aneurysms is superior to medical treatment, with the operative method involving vascular graft without concomitant aortic valve replacement as well as the method described by Wheat having both proved successful.

Acute Disease↗