Shunting Research Articles

Alveolar-arterial oxygen tension gradients in cirrhosis of the liver: Further evidence of existing pulmonary arteriovenous shunting

Alveolar-arterial oxygen tension gradients in cirrhosis of the liver: Further evidence of existing pulmonary arteriovenous shunting

ATELECTASIS AND SHUNTING.

ATELECTASIS AND SHUNTING.

Experimental studies in surgery of small blood vessels. II. Patching of arteriotomy using a plastic adhesive.

ASTOMOSIS by suturing, patching, and shunt ing of small arteries and veins 4 ram. or less in external diameter car ry a high incidence of failure because of constrict ion and thrombosis, as compared to vessels of larger d iameter (5-6 ram. and larger). I t is true t ha t Seidenberg et al. 12 repor ted excellent results by meticulous direct anastomosis of small arteries with sutures, using 7-0 braided silk. 13 However, application of this technique to surgery of intracranial vessels presents additional difficulties, such as: (1) difference in structure of cerebral arteries ~ as compared to extraeerebral vessels, with less adventit ia, reduced media, absent external elastic membrane , ~ and minimal suppor t by surrounding tissues; (~) the presence of perforat ing branches precluding rota t ion; (3) l imitation of t ime of vascular occlusion (even with the use of hypothermia) ; and (4) lack of maneuverabi l ity. With a few exceptions, u,15 patency of the a r te ry has been lost, or could not be reestablished, following such a t t empts in m a n . 8-11,14,15

A hemodynamic study of atrial septal defect and associated anomalies involving the atrial septum.

Abstract An interatrial communication was found as a significant lesion in a total of 121 patients studied up to 1954 in the cardiac catheterization laboratory of the Mayo Clinic. Of these patients, 44 were considered to be examples of uncomplicated atrial septal defect, 13 had associated pulmonary hypertension, 6 had anomalous connection of one or more pulmonary veins, 6 had persistent common atrioventricular canals, and 2 had mitral valve disease. The hemodynamic data obtained from these 71 patients form the basis for this report. In the patients without pulmonary hypertension the pulmonary blood flow was greatly increased (average 8.3 L./min./M. 2 ) due to the presence of left-toright shunting of considerable degree. In a number of these patients it was demonstrated that of the blood shunted left to right, a greater proportion originated from the right lung than from the left lung. Small right-to-left shunts without hemodynamic significance were shown to exist frequently, and of the blood shunted right to left a greater proportion was of inferior caval than of superior caval origin. In these patients the systemic blood flow was normal. The majority of patients with severe pulmonary hypertension had pulmonary and systemic flows of reduced magnitude. In 2 patients with severe pulmonary hypertension a large pulmonary blood flow was calculated. Patients with anomalous connection of one or more pulmonary veins or with common atrioventricular canal may show the same fundamental circulatory disorder as patients with an atrial septal defect of the usual type. The frequency and practical importance of each of these lesions are compelling reasons that they be sought and diagnosed preoperatively. Highly suggestive evidence for each of these lesions may be obtained from critical analysis of the oxygen saturation of separate series of samples of blood drawn from different locations in the right ventricle, right atrium and both venae cavae. Differences of some magnitude may exist between samples drawn at random from these sites, but considerable significance may be placed on a difference that is consistently demonstrated. A significant correlation was demonstrated between the pressure gradient across the pulmonary valve frequently found in these patients and the magnitude of the pulmonary blood flow. The gradient did not appear to be associated with a pathologically significant degree of pulmonary stenosis.