Studies on hemodynamics and cardiac function in the immediate postoperative period following open heart surgery

Hemodynamics and cardiac function in the immediate postoperative period following open heart surgery were studied by means of a Swan-Ganz catheter and a thermodilution output computer. Pulmonary arterial pressure decreased at 3 hr after operation in congenital and mitral valvular diseases either with or without pulmonary hypertension. Then pulmonary arterial pressure maintained the decreased level subsequently in patients without pulmonary hypertension or with moderate pulmonary hypertension. However, in cases of severe pulmonary hypertension, pulmonary arterial pressure increased concomitantly with the increase of pulmonary arterial resistance in adult cases, but maintained the decreased level in juvenile cases. Pulmonary wedge pressure decreased to 3 hr after operation and maintained the decreased level. Right atrail pressure fluctuated within normal range. The cardiac index and left ventricular stroke work index increased between 3 to 6 hr after operation in congenital and mitral valvular diseases and decreased temporarily between 9 to 30 hr and then increased again. The cardiac index and left ventricular stroke work index in mitral valvular diseases showed values lower than those in congenital heart diseases. The increase of cardiac index and left ventricular stroke work index after open heart surgery was more remarkable in mitral valvular diseases than in congenital heart diseases.