Recent advances in studies on cardiac structure and metabolism
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Recent Adv Stud Cardiac Struct Metab · Jan 1975
Effects of inhalation anesthetics on cardiac function and metabolism in the intact dog.
In healthy, closed-chest dogs, dose-dependent depression of ventricular function was produced by the anesthetics halothane, methoxyflurane, and fluroxene, as evidence by decreases in left venticular stroke volume, stroke work, dP/dt, and an increased enddiastolic pressure. Myocardial blood flow and oxygen consumption decreased concomitantly and were correlated with aortic blood pressure decreases. ⋯ The hemodynamic effects of halothane and methoxyflurane are similar to those previously reported in man, but those of fluroxene are different. Consequently, clinical speculation from these results is not justified at this time.
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Recent Adv Stud Cardiac Struct Metab · Jan 1975
Effect of deep hypothermia, limited cardiopulmonary bypass, and total arrest on growing puppies.
The advantages of a bloodless field and total cardiac relaxation have popularized the technique of deep hypothermia and total circulatory arrest for the correction of complex congenital cardiac defects in infancy. There is, however, a significant potential for cerebral and pulmonary complications. Presently, the most common technique is that of using a combination of surface cooling and cardiopulmonary bypass cooling and rewarming. ⋯ Puppies that were continuously on cardiopulmonary bypass had no significant pulmonary changes caused by increasing the inspired oxygen tension in the ventilator; however, striking changes were noted when limited cardiopulmonary bypass was employed for core cooling and total circulatory arrest combined with pulmonary ventilation with 100% oxygen. We conclude from this experimental study that the use of surface cooling and core cooling with subsequent total circulatory arrest at 20 degrees C is a safe procedure, providing the period of time of cardiac arrest is kept around 30 min. We also conclude that the alveolar oxygen tension should be maintained at the lowest level possible during the interval of circulatory arrest to avoid the apparent rapid onset of post-traumatic pulmonary insufficiency.