[The effects of dopamine on the renin-angiotensin-aldosterone system after extracorporeal circulation]

Thirty-one patients underwent elective coronary bypass grafting were studied about the effects of dopamine (DOP) on the renin-angiotensin-aldosterone system (RAAS) for 24 hours after extracorporeal circulation (ECC). All of them had no evident of renal dysfunction nor other complication preoperatively. Patients were divided according to the administration of DOP 5-10 micrograms/kg/min (group D, n = 16) and control group without any catecholamine including DOP (group N, n = 15). Criteria for DOP administration were systolic blood pressure less than 100 mmHg and central venous pressure greater than 15 cmH2O. Hemodynamically no significant difference was observed between the two groups. The RAAS was activated by ECC in both groups. Plasma renin activity (PRA) and plasma angiotensin II-levels (AII) returned to normal range at 6 hours after ECC in group D which is significantly less than group N where PRA and AII remained elevated at 24 hours after ECC. Plasma aldosterone levels (ALD) did not show any significant difference between the two groups. AII changed proportionately to PRA, whereas ALD did not correlate with PRA or AII in the both groups. These results suggested that in early postoperative period angiotensin II didn't cause peripheral vasoconstriction in group D, and administration of DOP in doses of 5-10 micrograms/kg/min resulting in a low level of AII is safe and useful in view of data that a high AII promotes multifocal myocardial necrosis and renal tubular degeneration.