Fluids, Nutrition, and Acute Kidney Injury in Pediatric Acute Respiratory Distress Syndrome

Abstract

Fluid and nutrition support are essential components of intensive care management of children with pediatric acute respiratory distress syndrome (PARDS) with well-recognized associations with patient outcome. As liberal fluid administration is associated with fluid accumulation and, in turn, worse oxygenation, adequate nutrition delivery could potentially create a competing goal. However, receipt of a higher proportion of goal energy and protein is associated with improved patient outcome in PARDS. Nutrition support is often limited or fails to meet energy and protein goals due to delayed initiation of feeds, interruptions for ICU procedures, feeding intolerance, and to prevent or manage existing fluid overload. Despite contrary evidence, additional restriction of daily protein delivery often accompanies restrictive fluid management for children with severe PARDS with acute kidney injury (AKI). The balanced management of nutritional status, fluid overload, and AKI presents unique challenges when caring for children with PARDS. Careful multidisciplinary team-based care is necessary to prescribe guideline-recommended minimum macronutrient needs to preserve lean body mass and optimize respiratory muscle function, to avoid fluid overload, and coordinate care for AKI. American Society for Parenteral and Enteral Nutrition (ASPEN) and Society of Critical Care Medicine (SCCM) recommendations for provision of nutrition in critically ill children include (1) early screening of nutritional status to identify patients at high nutritional risk; (2) use of predictive equations to determine energy requirements without the addition of stress factors when indirect calorimetry (IC) is not available; (3) target energy for the first week of critical illness should be at least 2/3 of total energy requirements; (4) minimum protein delivery is 1.5 g/kg/day; (5) enteral nutrition (EN) is the preferred route of nutrition delivery, should be initiated within 24–48 hours of ICU admission, and should be advanced by a stepwise institutional algorithm; and (6) parenteral nutrition (PN) should be delayed at least 24 hours after ICU admission and initiated only for children who cannot be fed enterally during their first week of ICU stay, or for children with baseline high nutritional risk who cannot tolerate more than low volumes of EN. Current nutritional guidelines recommend modest energy goals, and with the possibility of low-volume protein supplementation, it is possible to achieve goal nutrition and avoid fluid overload due to nutrition delivery in most patients. Therapies currently used to treat and manage fluid overload in PARDS with and without AKI include fluid restriction, diuretics, and continuous or intermittent renal replacement therapies. Careful monitoring of protein tolerance, but not protein restriction, is needed in the setting of AKI. If renal replacement therapies are needed for AKI, optimal nutrition delivery should take into account dialysis-associated nutrient losses. In this chapter, we will review the principles of management for fluid, nutrition, and AKI in children with PARDS.