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Biomedical subjects

J B Borman

Publications and source records attributed to J B Borman.

At least 73 records · Page 4Linked to original sources
PubMed1980

Afterload reduction and cardiac output in patients after mitral valve surgery.

Thirteen patients who had mitral valve surgery were studied within 3 hours after operation. The patients were divided into 2 groups: group A with initial low cardiac index (1.70 +/- 0.25), elevated left atrial pressure (16.5 +/- 6.7) and high peripheral vascular resistance (2623 +/- 789); group B with initial normal cardiac index (3.71 +/- 0.54), normal left atrial pressure (13 +/- 3.5) and normal peripheral vascular resistance (1223 +/- 303). In both groups the mean arterial pressure was elevated (98 +/- 8.8, 96 +/0 15.8). An infusion of nitroprusside to reduce the mean arterial pressure to either 80 mmHg or 10% below the initial value had different effects in each group. In group A, cardiac index (CI) increased by 23%, left atrial pressure (LAP) decreased by 20%, pulmonary artery pressure (PAP) by 35%, and peripheral vascular resistance (PRV) by 32%. In group B, CI decreased by 8%, LAP by 32%, PAP by 30% and PVR by 13%. When LAP returned to initial values after an infusion of blood with continued infusion of nitroprusside, CI increased in both groups (27%, 11%) and the PVR remained lower (40%, 29%). The study demonstrates the favorable effect on cardiac output of vasodilator therapy on patients with elevated blood pressure, impaired by left ventricular function and high LAP, after surgery on mitral valve. The optimal effect is achieved by keeping the LAP within normal limits.

Adolescent↗
PubMed1980

Computer simulation: a diagnostic method in comparative studies of valve prostheses.

Computer simulation was used to compare flow characteristics through Starr-Edwards and Björk-Shiley valves in the mitral and aortic positions. Pressure and velocity determinations were mathematically computed with the use of a model based on the recognition that blood is a non-Newtonian fluid. The results were displayed in two-dimensional graphic form. In both the mitral and aortic positions the Björk-Shiley prosthesis showed a more favorable laminar flow pattern, producing fewer eddies and smaller pressure and velocity gradients through the occluder. Computer simulation is a valuable adjunct in the comparative testing of the hemodynamic properties of artificial heart valves and offers several advantages over physical simulators.

Aortic Valve↗
PubMed1979

A new method of sternal reclosure.

A new method is described for stabilizing dehiscence or instability of median sternotomy incisions using stainless steel retention sutures. The method has been used successfully in patients who had disruption of the sternum following open-heart surgery and resulted in no complications. It is recommended also as a preventive measure for closure of the sternum in elderly, debilitated patients with a fragile sternum and with prolonged low cardiac output after operation.

Aged↗
PubMed1979

Diagnostic value of cross-sectional echocardiography in left atrial myxoma.

Atrial myxoma is a rare condition that may have unusual clinical manifestations. Two patients with left atrial myxoma are described. One presented with paroxysmal nocturnal dyspnea and no abnormal physical signs on clinical examination; the second presented with palpitations and physical findings suggestive of mild mixed mitral valve disease. Echocardiography and cross-sectional echocardiography confirmed the diagnosis of atrial myxoma in both patients, and the tumors were successfully removed by operation. Cross-sectional echocardiography may obviate the need for cardiac catheterization in patients with left atrial tumors.

Echocardiography↗
PubMed1977

The hemodynamic effects of dopamine following cardiopulmonary bypass.

The hemodynamic effects of dopamine were studied in 19 patients following intracardiac operation or myocardial revascularization using extracorporeal circulation. The heart rate, mean blood pressure, central venous pressure, left atrial and pulmonary artery pressures, cardiac output, and urine output were recorded before and at the end of one-hour infusions of dopamine at 5, 10, and 15 mug/kg/min. Infusion of 5 mug/kg/min of dopamine resulted in the highest gain in cardiac output and stroke work without an increase in myocardial oxygen consumption, as evidenced by lack of significant rise in heart rate. In addition, this dosage was not accompanied by an increase in pulmonary or systemic vascular resistance, nor were other untoward effects observed after administration of 5 mug/kg/min of dopamine.

Blood Pressure↗
PubMed1977

Preoperative intermittent positive pressure respiration as preparation for emergency valvular surgery for pulmonary edema.

Immediate emergency surgery is the accepted treatment of intractable pulmonary edema due to valvular heart disease. The presence of severe tissue hypoxia, acidosis, low cardiac output state and renal insufficiency results in a high operative risk. Delay of operation by several hours may prove advantageous in that it permits improvements of the patient's condition by means of intermittent positive pressure respiration with correction of acidosis and at the same time allows for treatment of the cardiac failure. Three illustrative cases are presented, all successfully managed by preoperative treatment in an intensive care unit. The pathophysiological basis of this therapeutic approach is discussed.

Adolescent↗
PubMed1977

Echocardiographic left ventricular function in aortic and mitral incompetence and the effect of valve replacement.

Left ventricular (LV) function was studied by echocardiography in 28 patients with volume overload of the LV before and after valve replacement. Of the 28 subjects, 19 had mitral valve disease (eight with mitral incompetence and 11 with mitral incompetence and stenosis) and nine patients had aortic incompetence. Patients with chronic mitral and aortic incompetence had marked LV enlargement with normal or slightly depressed systolic function; in those with acute mitral incompetence the degree of cardiomegaly was less and the state of LV function depended on the underlying cause of valvular incompetence. Valve replacement was followed by a decrease in LV end-diastolic volume and this occurred in the first week after operation. There was a gradual improvement in LV function in some patients, as measured by normalized mean velocity of posterior LV wall motion. Paradoxical septal motion occurred in many patients after operation but improved in the late postoperative period.

Adolescent↗
PubMed1975

Quadruple valve commissurotomy.

A 12-year-old girl in congestive heart failure was diagnosed to be suffering from severe polyvalvular disease due to a combination of congenital and rheumatic lesions. Cardiac catheterization demonstrated stenotic lesions of all the heart valves. The child underwent quadruple valve commissurotomy and is symptom free and thriving 2 years later.

Child↗
PubMed1975

The influence of cardiopulmonary bypass on the size of human platelets.

Large and small platelets are present in the bloodstream in nearly equal proportions and comprise about 30 per cent of the normal platelet population. The assumption that cardiopulmonary bypass may alter this platelet population distribution was investigated. Platelet volume distribution curves during and after cardiopulmonary bypass were examined in 12 patients undergoing various intracardiac operation by an electronic particle-sizing apparatus based on the Coulter counter. Mean platelet volume (MPV) was 8.6 +/- 0.7 cubic microns prior to cardiopulmonary bypass. Ten minutes after commencement of cardiopulmonary bypass the MPV decreased to 85 per cent of control levels. A further decrease, reaching a plateau at 75 per cent of prebypass MPV, was reached after 50 minutes on bypass. MPV returned to 87 per cent of prebypass levels 2 hours after discontinuation of cardiopulmonary bypass. Since it is known that platelet count is markedly reduced on cardiopulmonary bypass, a simultaneous 25 per cent decrease in MPV can be explained only by a highly selective disappearance of the large platelets from the circulation. As the larger platelets are younger and functionally more potent than the smaller ones, the selective disappearance of large platelets may thus provide an explanation for the observed alteration in platelet adhesiveness caused by cardiopulmonary bypass.

Blood Cell Count↗