Risks of acute renal failure after cardiopulmonary bypass surgery in children: a retrospective 10-year case-control study

To our knowledge there are no case-control studies that have examined the main risk factors for acute renal failure (ARF) following cardiopulmonary bypass surgery in children. We therefore evaluated the potential risk factors in a large retrospective case-control study. Sixty-one of 2262 children (2.7%) developed postcardiopulmonary bypass surgery ARF requiring peritoneal dialysis (PD) from 1982 to 1991. Fifty-eight of 61 cases (median age 8.5 months) were selected by systematic sampling and matched with 176 controls who did not develop ARF. The four matching variables were age, cardiopulmonary bypass and circulatory arrest duration, and year of operation. Mortality rate was 79% in cases (controls: 18%). Forty-three of 48 of the deceased cases did not recover renal function; no renal cause of death was found; 13 of 61 cases survived and recovered renal function. Multiple regression analysis showed the following significant risk factors for postcardiopulmonary bypass surgery ARF: central venous hypertension >12 h (odds ratio (OR) 9.6); systolic arterial hypotension >12 h (OR 8.9); dopamine dosage >15 μg/kg/min (OR 3.0); adrenaline (OR 5.9) and isoproterenol (OR 13.5) use. High preoperative serum creatinine, cyanosis, and vasodilator use were not significant risk factors. We conclude that: (1) haemodynamic alterations were the main cause of postcardiopulmonary bypass surgery ARF; (2) ARF was associated with but was not the cause of the high mortality rate; (3) the risk of ARF increased almost 10-fold after 12 h of central venous hypertension and/or of systolic arterial hypotension; (4) effective dosages of inotropes might have been a risk factor for ARF; (5) a slight precardiopulmonary bypass surgery reduction of renal function alone did not represent an increased risk for ARF.