Clinical Investigation Of Acute Renal Failure Following Cardiac Surgery

OBJECTIVE Acute renal failure (ARF) is one of the most common and severe complication in patients after cardiac surgery. Therefore how to prevent and successfully treat ARF post cardiac surgery is still a concern of cardiac surgeons. This study analyse the risk factors of ARF in cardiac surgery patient with cardiopulmonary bypass and without cardiopulmonary bypass, to establish early diagnosis and to evaluate the efficacy of diuretic therapy and blood purification therapy, thereby reducing the occurrence of ARF and decreasing the mortality of ARF after cardiac surgery. METHOD During the period of January 1993 to December 2007, 45 cases who had developed ARF from a total of 879 cases following cardiac surgery were taken into study, which were 35 cases with cardiopulmonary bypass and 10 cases without cardiopulmonary bypass. 42 and 34 patients undergoing cardiac surgery at the same period were randomly selected as control case. The occurrence and risk factors of ARF developing after cardiopulmonary bypass and without cardiopulmonary bypass were identified through regression analysis using multi-factor analytical method. The post cardiac surgery ARF 45 cases all went through diuresis treatment. If diuresis has no effect, immediate purification treatment (hemodialysis, hemofiltartion) were undertaken. RESULTS Total ARF occurrence post cardiac surgery was 5.12%, which was 5.07% with cardiopulmonary bypass surgery, and 5.29% without cardiopulmonary bypass surgery. The most important risk factors for those with the use of cardiopulmonary bypass are post surgical hypotension (P<0.001), pre-existing renal dysfunction (P<0.05). Among the 45 cases of ARF after dialysis treatment, 35 cases (77%) had increased urine output after 3-5h, within 7-35h returned to normal, other 10 cases (23%) had no noticeable increase in urine and creatinine continued to increase. Therefore blood purification treatment (dialysis, filtration). Of the 10 cases, 5 cases had hemodialysis, 5 cases had filtration. The clinical situation of pre and post dialysis and filtration treatment in two groups had significiant difference. Especially in filtration groups, pre and post filtration treatment indicators (average blood pressure, urea nitrogen, creatinine, oxygen partial pressure) were significant improved. Among the patients of blood purification treatment, 5cases died the mortality 50%, 3 cases in dialysis, 2 cases in filtration. The main cause of the death was the multi organ failure. 40 cases of the discharged ARF cases underwent visit, 5 cases died, the cause of deaths is multi organ failure. Conculsion Pre-existing hypertension and post surgical hypotension is the independent risk factor of ARF after cardiac surgery. In surgical environment, correct method of disposition is most important in the preventive treatment of the ARF, and urgent diagnosis and early treatments like diuresis and active blood purification are the key factors of successive emergency treatment of post cardiac surgical ARF.