Various fluid removal strategies are utilized to mitigate the deleterious effects of fluid accumulation in neonates following cardiac surgery. We aim to describe practice patterns and identify associations of fluid management strategies with outcomes in neonates undergoing cardiac surgery using the Neonatal and Pediatric Heart and Renal Outcomes Network dataset.

Multicentre retrospective study including neonates who underwent cardiac surgery between 2015 and 2018. Primary outcomes were duration of mechanical ventilation, delay in first negative daily fluid balance, peak cumulative fluid balance, and severe persistent acute kidney injury. Multivariable logistic and ordinal regression models assessed associations between fluid removal strategies and clinical outcomes.

Of 2,240 neonates, 25% (n = 560) received furosemide in the operating room. Peritoneal catheters were placed in 24% (n = 527), and 8.6% (n = 193) underwent prophylactic peritoneal dialysis. Diuretic use on postoperative day 0 ranged 6–95% across institutions. Diuretics on postoperative day 0 were associated with shorter time to negative daily fluid balance (odds ratio 0.55; 95% confidence interval 0.30–0.995) and shorter duration of mechanical ventilation (odds ratio 0.58; 95% confidence interval 0.39–0.86). Intraoperative diuretics were also associated with shorter duration of mechanical ventilation (odds ratio 0.60; 95% confidence interval 0.42–0.86). Receipt of continuous diuretic infusion on postoperative day 0 or 1 was associated with longer duration of mechanical ventilation (odds ratio 3.02; 95% confidence interval 1.98–4.58). No association of diuretic use with severe persistent acute kidney injury was found.

Early use of diuretics in neonatal cardiac surgery is highly variable and has a differential association with outcomes. Future studies that standardize the dose, timing, and mode of administration (intermittent vs continuous) of diuretics are warranted to identify potential associations with outcomes.

The use of peritoneal catheters for prophylactic dialysis or drainage to prevent fluid overload after neonatal cardiac surgery is common in some centres; however, the multi-centre variability and details of peritoneal catheter use are not well described.

Twenty-two-centre NEonatal and Pediatric Heart Renal Outcomes Network (NEPHRON) study to describe multi-centre peritoneal catheter use after STAT category 3–5 neonatal cardiac surgery using cardiopulmonary bypass. Patient characteristics and acute kidney injury/fluid outcomes for six post-operative days are described among three cohorts: peritoneal catheter with dialysis, peritoneal catheter with passive drainage, and no peritoneal catheter.

Of 1490 neonates, 471 (32%) had an intraoperative peritoneal catheter placed; 177 (12%) received prophylactic dialysis and 294 (20%) received passive drainage. Sixteen (73%) centres used peritoneal catheter at some frequency, including six centres in >50% of neonates. Four centres utilised prophylactic peritoneal dialysis. Time to post-operative dialysis initiation was 3 hours [1, 5] with the duration of 56 hours [37, 90]; passive drainage cohort drained for 92 hours [64, 163]. Peritoneal catheter were more common among patients receiving pre-operative mechanical ventilation, single ventricle physiology, and higher complexity surgery. There was no association with adverse events. Serum creatinine and daily fluid balance were not clinically different on any post-operative day. Mortality was similar.

In neonates undergoing complex cardiac surgery, peritoneal catheter use is not rare, with substantial variability among centres. Peritoneal catheters are used more commonly with higher surgical complexity. Adverse event rates, including mortality, are not different with peritoneal catheter use. Fluid overload and creatinine-based acute kidney injury rates are not different in peritoneal catheter cohorts.