Changes in systemic vascular resistance and cardiac output during mitral valve replacement

ABSTRACT

Systemic vascular resistance and cardiac output were measured during mitral valve replacement for twenty patients with relatively good left ventricular function. Measurements taken prior to induction of anaesthesia were considered as control values. The systemic vascular resistance showed significant increase associated with highly significant decrease in cardiac output before the begining of cardiopulmonary bypass. Ten minutes after commencement of bypass there was very high significant decrease of systemic vascular resistance. During bypass the resistance started to increase, but it did not reach the control value at the end of hypass. During sternaI closure and one hour post operatively the systemic vascular resistance was still below the control value but associated with significant increase in cardiac output. There was highly significant negative correlation between the systemic vascular resistance and the cardiac output before and after bypass