Acute renal failure and outcome of continuous arteriovenous hemodialysis (CAVHD) and continuous hemofiltration (CAVH) in elderly patients following cardiovascular surgery.

A total of 111 elderly patients from the cardiac surgery intensive care unit (ICU) with acute renal failure (ARF) were studied during a period of 7 years (1988-1994). Forty-two patients being operated for coronary bypass (CBP) (31 M, 11 F), 26 patients for valve replacement (VR) (18 M, 8 F), 20 patients for a combined operation of coronary bypass and valve replacement (CBP+VR) (14 M, 6 F) and 23 patients for resection of aneurysm of the abdominal aorta (ROAOAA) (11 M, 12 F). Average age of the patients was 70 +/- 4 yr (65-80). Their blood pressure on the first day of continuous renal replacement therapy (CRRT) was 75 +/- 19 mmHg (50-95) and was maintained at about 95 +/- 15 mmHg (70-120) by using vasopressor drugs. From the results of this study a survival of 38% was registered within the CBP group, 65% within the VR group, 45% within the CBP+VR group and 91% within the ROAOAA group. The overall survival in all of the patients was 58%. It was a high mortality (62%) within CBP group compared to that of 35%, 55% and 9% within the VR, CBP+VR and ROAOAA groups, respectively. This is because more patients with predisposing preoperative risk factors, e.g., hypertension (33%) and Diabetes (17%) etc were found in the CBP group, in addition to their post operative complications of which bleeding necessitating reoperations was encountered in 31%. Multiple organ failure (MOF) was a common major problem of which respiratory failure needing artificial ventilation was encountered in about 90% of the patients. The overall mortality was 42% in which the major cause of death was MOF/circulatory failure. Heart failure was the second cause of death. Other secondary complications, e.g., liver failure (n = 6) and atrial fibrillation (n = 11) etc. might have added to the high mortality in this study. The effect of CRRT on uremic control was measured by following-up of the daily levels of the serum urea and creatinine and a steady-state uremic control was achieved. We conclude that CRRT can be considered as a reliable artificial renal support for ARF in ICU elderly patients.