Fluid Restriction Contributes to Poor Nutritional Adequacy in Patients With Congenital Heart Disease Receiving Renal Replacement Therapy.

Objectives: Critically ill patients receiving renal replacement therapy (RRT) in the pediatric cardiac intensive care unit (CICU) are at high risk for inadequate nutrition delivery. The objective of this study is to evaluate barriers to adequate energy and protein delivery in critically ill patients with congenital heart disease receiving RRT.

Methods: This is a single-center retrospective cohort study of patients receiving RRT in the CICU from 2011 to 2019. Energy and protein adequacy was recorded over the first 7 days of RRT. Adequacy was defined as delivery of >80% of the energy and protein targets during this time period. Patients who achieved adequacy were compared to those who did not. Multivariable logistic regression models were constructed to determine factors independently associated with energy and protein adequacy while receiving RRT.

Results: Sixty patients were included for analysis. Fifty-five patients (92%) achieved energy adequacy and 37 patients (62%) achieved protein adequacy. A higher weight-for-age z-score (WAZ) on admission to the CICU was the only independent predictor of inadequate energy intake (odds ratio 0.07, 95% confidence interval 0.01-0.58, P = .014); median WAZ was -1.17 versus +1.24 for those with adequate versus inadequate energy intake, respectively. Fluid restriction to <80% of maintenance fluid at the time of RRT initiation was more likely in patients with higher WAZ. Fluid restriction was the only independent predictor of inadequate protein intake (odds ratio 0.13, 95% confidence interval 0.02-0.7, P = .018); 5% versus 30% were fluid restricted in those with adequate versus inadequate protein intake, respectively. Azotemia was not associated with inadequate protein intake. Initiation of RRT did not allow for liberalization of fluid intake over the time period evaluated.

Conclusions: Protein delivery was inadequate in 38% of children undergoing RRT in the CICU. Fluid restriction was associated with inadequate protein intake and higher WAZ was associated with inadequate energy intake.