Objective:To observe the early effects of dopamine on patients undergoing mitral valve replacement after cardiac pulmonary bypass on left ventricular contraction,hemodynamics and urine volume,so as to revaluate the clinical effects of dopamine on patients undergoing open heart operation. Methods:Eighteen patients with American Society of Anesthesiologists Status(ASA)Ⅱ~Ⅲ,age≤70 years,male or female,preoperatively NYHAⅡ~Ⅲ,EF≥45% and without using cardiotonic agents,scheduled for mitral valve replacement were studied. Complete intravenous general anesthesia was used in anesthesia induction and during intraoperative anesthesia. The patients were divided into two groups,including the D group(n = 8) and the F group(n = 10). The D group:after cardiac pulmonary bypass with continuous infusion dopamine intravenously; thr F group:without receiving dopamine intravenously. With controlling the coincidence of ventricular rate by pacemaker,cardiac index(CI),left ventricular ejection fraction(LVEF),central venous pressure(CVP),mean arterial pressure(MAP),systemic vascular resistance index(SVRI),the value of lactic acid,urine volume and phenylephrine dosage were compared between two groups after cardiac pulmonary bypass. Results:Within the group D and F,the values of the examinations had no statistical significance (P > 0.05). Except that the LVEF at the points 30 min and 60 min of the group F were more than the group D,there were no differences in the levels of CI,LVEF,CVP,MAP,SVRI,urine volume and phenylephrine dosage between the two groups at the same points(P > 0.05). However,the urine volume of the groups D and F had statistical significance(P < 0.05),and lactic acid value at the same points between both of the groups were significantly different (P < 0.01). Conclusion:In this study,the result suggested that it isn’t necessary for the normal heart function of the patients undergoing mitral valve replacement after cardiac pulmonary bypass to receive prophylactic dopamine,but obviously increasing urine output and the clearance of lactic acid.