Mah KE, et al. - Fluid overload (FO) is common after neonatal congenital heart surgery and may contribute to mortality and morbidity. This study was designed to investigate whether the impacts of FO are independent of acute kidney injury (AKI). Findings showed an independent and important contribution of FO to outcomes in neonates following congenital heart surgery. These results called for careful fluid management after cardiac surgery in neonates with and without AKI.

• Neonates (age < 30 days) who underwent cardiopulmonary bypass in a university-affiliated children’s hospital between 20 October 2010 and 31 December 2012, were retrospectively scrutinized.
• Researchers recorded demographic information, risk adjustment for congenital heart surgery score, surgery type, cardiopulmonary bypass time, cross-clamp time, and vasoactive inotrope score.
• They calculated FO [(fluid in–out)/pre-operative weight] and AKI defined by Kidney Disease Improving Global Outcomes serum creatinine criteria.
• Outcomes included all-cause, in-hospital mortality and median postoperative hospital and intensive care unit lengths of stay.

• Of a total of 167 neonates who underwent cardiac surgery using cardiopulmonary bypass in the study period, 117 met the inclusion criteria.
• A total of 117 neonates were included in the study.
• Of those, significant FO (>10%) was detected in 76 (65%) patients, and 25 (21%) developed AKI ≥ Stage 2.
• Findings revealed that when analyzed as FO cohorts (< 10%,10–20%, > 20% FO), patients with greater FO were more likely to have AKI (9.8 vs 18.2 vs 52.4%, respectively, with AKI ≥ stage 2; p=0.013) and a higher vasoactive-inotrope score, and be premature.
• An independent association of FO with hospital and intensive care unit lengths of stay [0.322 extra days (p=0.029) and 0.468 extra days (p < 0.001), respectively, per 1% FO increase) was shown in the multivariable regression analyses of patients without AKI.
• Association of FO with mortality was observed in all patients [odds ratio 1.058 (5.8% greater odds of mortality per 1% FO increase); 95% confidence interval 1.008,1.125;p=0.032].