Perioperative circulating blood volume and cardiac function in valve disease

Circulating blood volume is important in managing fluid balance and cardiac function after surgery under cardiopulmonary bypass. Appropriate management differs among the valve disorders, but perioperative blood volume has not yet been considered. From February 2001 to March 2003, perioperative blood volume, fluid balance, cardiac index, and left ventricular stroke work index were measured in 31 patients: 10 with aortic stenosis, 9 with aortic regurgitation, 3 with mitral stenosis, and 9 with mitral regurgitation. All immediate postoperative blood volume measurements were less than preoperative values, and gradually returned to baseline. At all time points, blood volume in patients with aortic or mitral regurgitation was high, whereas it was low in those with stenosis, especially mitral stenosis. Fluid balance was positive in all patients. Postoperatively, there was a positive correlation between cardiac index and blood volume in all groups. The left ventricular stroke work index in the mitral regurgitation group was significantly higher than other groups, the aortic stenosis group was slightly lower, the mitral stenosis and mitral regurgitation groups were higher than the baseline, and the aortic regurgitation group was essentially unchanged. Thus, it is necessary to consider blood volume perioperatively in different valvular diseases to manage water balance.