Peritoneal dialysis does not adversely affect kidney function recovery after congenital heart surgery

Acute kidney injury (AKI) after cardiopulmonary bypass surgery to correct congenital heart disease is common. We prevent fluid overload and further cardiac compromise in oliguric infants with continuous peritoneal dialysis (CPD). The effect of CPD on kidney recovery is unknown, thus indications to discontinue CPD are unclear. We aimed to determine if CPD affects kidney recovery, measured by urine output and novel urinary AKI biomarker concentrations.

Twenty infants <90 days old with congenital heart disease who underwent bypass surgery and were post-operatively treated with CPD were randomized at the time of clinical readiness for CPD discontinuation to 1) discontinue CPD (control) or 2) continue 24 h more CPD (experimental). Urine output (ml/kg per h), total output (ml/kg per h) and urinary neutrophil gelatinase-associated lipocalin, interleukin-18, liver-type fatty acid binding protein, and kidney injury molecule-1 were assessed post-surgery until CPD catheter removal.

24 hours preceding randomization, there were no differences in mean urine output or total output; 24 hours post-randomization, the control group had higher mean urine output (4.2 ± 2.6 ml/kg per h vs. 2.8 ± 2.0 ml/kg per h, p = 0.02) but lower total output (6.3 ± 2.1 ml/kg per h vs. 4.7 ± 2.7 ml/kg per h, p = 0.01). Median biomarker concentrations did not differ significantly between groups at any time point.

Our results suggest renal replacement therapy does not change the time course of kidney function recovery.