Evolution and mortality risk factors in children with continuous renal replacement therapy after cardiac surgery

To study the clinical course of children requiring continuous renal replacement therapy after cardiac surgery and to analyze factors associated with mortality.

A prospective observational study was performed that included children requiring continuous renal replacement therapy after cardiac surgery. Univariate and multivariate analyses were performed to determine the influence of each factor on mortality. We compared these patients with other critically ill children requiring continuous renal replacement therapy.

Of 1650 children undergoing cardiac surgery, 81 (4.9%) required continuous renal replacement therapy, 65 of whom (80.2%) presented multiple organ failure. The children who started continuous renal replacement therapy after cardiac surgery had lower mean arterial pressure, lower urea and creatinine levels, and higher mortality (43%) than the other children on continuous renal replacement therapy (29%) (P=.05). Factors associated with mortality in the univariate analysis were age less than 12 months, weight under 10 kg, higher pediatric risk of mortality score, hypotension, lower urea and creatinine levels when starting continuous renal replacement therapy, and the use of hemofiltration. In the multivariate analysis, hypotension when starting continuous renal replacement therapy, pediatric risk of mortality scores equal to or greater than 21, and hemofiltration were associated with mortality.

Although only a small percentage of children undergoing cardiac surgery required continuous renal replacement therapy, mortality among these patients was high. Hypotension and severity of illness when starting the technique and hemofiltration were factors associated with higher mortality.