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Biomedical subjects

M A Heymann

Publications and source records attributed to M A Heymann.

197 records · Page 11Linked to original sources
PubMedDate not supplied

Evaluation of alprostadil (prostaglandin E1) in the management of congenital heart disease in infancy.

Prostaglandins have been shown to relax the smooth muscle of the ductus arteriosus in the fetus in utero. This physiologic action has been applied to the management of newborn infants with certain types of congenital malformations. Infants with lesions producing right ventricular outflow obstruction have a compromised pulmonary circulation and require a patent ductus arteriosus for adequate pulmonary blood flow. Infusion of alprostadil (PGE1) dilates the ductus, increases pulmonary blood flow, and thereby improves oxygenation. Likewise, infants with aortic arch interruption or coarctation of the aorta are dependent on an open ductus to maintain lower body perfusion. Alprostadil is of great benefit in this situation as well. The side effects of alprostadil include peripheral vasodilation and hypotension and, most importantly, apnea. Hyperpyrexia and jitteriness may also occur. Side effects occur only in about 20% of infants and usually are easily reversed. The benefits therefore greatly outweigh the risks, but careful monitoring is essential.

Alprostadil↗
PubMedDate not supplied

Isolated ventricular inversion: two-dimensional echocardiographic findings and a review of the literature.

In a cyanotic newborn infant, the diagnosis of isolated ventricular inversion in situs solitus was made from the two-dimensional echocardiographic examination and later confirmed at cardiac catheterization and surgery. The four-chamber views were especially useful for identifying the normal atrial situs and discordant atrioventricular connections in this infant. The normal relationships of the great arteries to each other (aortic valve rightward, posterior, and inferior to the pulmonary valve; great arteries coiled around each other) and to the ventricles (mitral-aortic fibrous continuity, well-developed subpulmonic conus) were well defined in the subcostal views. A review of the medical literature revealed a total of 12 cases of isolated ventricular inversion, most of which were diagnosed only at postmortem examination. The two-dimensional echocardiogram provides a rapid, safe technique for prompt diagnosis in these very sick cyanotic infants.

Cardiac Catheterization↗
PubMedDate not supplied

Blood flow measurements with radionuclide-labeled particles.

When appropriately and correctly applied, the microsphere technique is relatively simple and extremely accurate. Distribution patterns, both of total systemic arterial blood flow or venous return as well as within specific organs, can be measured. Several techniques have been applied to quantitate flow using microspheres; the reference sample method is extremely simple and by far the most accurate of all. Collection of venous effluent is perhaps more accurate but requires extensive surgery and is almost certainly the least physiologic. Other methods used for quantitation, such as bolus injections of indocyanine green dye or in fusions of diffusable indicators, are considerably less accurate and therefore significantly reduce the reliability of the microsphere technique. Selection of the appropriate size microspheres allows for definition of arteriovenous anastomoses as well as the measurement of organ blood flows and distribution of blood flow within those organs. In most instances, smaller microspheres (15mu diameter or 8-10mu diameter) have significant advantages over larger ones. They are distributed more like red cells, obstruct less of the vascular bed, are less variable in size, and can be given in significantly greater numbers. This latter point is important, since the statistical criteria need to be satisfied and the use of small spheres allows for the more reliable measurement of blood flow to small organs or to small regions of organs.

Animals↗