earlier, with obligate diastolic runoff and a potential “splanchnic steal”) or the PGE1 itself, because they are colinked variables It is believed that it is more likely that the physiology of a widely patent duct, rather than the PGE1 per se, places the intestines at risk, similar to the postoperative risk factors such as a wide pulse pressure and diastolic runoff mentioned earlier Nonetheless, the literature is replete with citing “PGE1” as the risk factor Of note, one study reported an increased incidence of feeding difficulties in neonates receiving a continuous intravenous infusion of PGE1 for longer than 2 weeks.51 Prolonged duration and dosing have also been associated with an increased risk of developing gastric outlet obstruction.51–54 Therefore neonates receiving PGE1 should be closely monitored for signs of feeding intolerance In some infants, deprivation of enteral nutrition may be unavoidable and parenteral nutrition is warranted However, a cautious introduction of preoperative enteral feeding may provide benefits including development of oromotor skills, maternal bonding, improved hemodynamics, and protective immunologic and GI benefits Umbilical Arterial Catheters The practice of using umbilical arterial catheters is widespread, although the evidence to support the safety of concurrently introducing enteral nutrition remains somewhat controversial Much of the known complications of these catheters is drawn from the literature on premature infants, rather than term infants with CHD No difference has been shown in flow through the superior mesenteric artery in neonates with or without such catheters,55 and others have found no increased incidence of problems with feeding.56 Despite the evidence supporting the use of enteral nutrition in premature infants with these catheters, nonetheless, the practice remains variable across centers Postoperative Nutrition Surgical outcomes can be greatly impacted by nutritional status and nitrogen balance Timely nutritional support is necessary for patients with CHD to maintain an adequate nutritional state and to minimize the physiologic consequences of undernutrition Nutrition support should be initiated as early as 24 to 48 hours postoperatively for neonates to promote wound healing, preserve lean body mass, and support metabolic function Energy requirements in the first few days following surgery may be decreased because of the catabolic stress mechanism inhibiting growth, decreased activity, and insensible losses The challenge is to provide minimum energy requirements to maintain metabolism, described in the literature as 40 to 70 kcal/kg per day.57–59 As the stress response dissipates, calories and protein should be optimized to promote synthesis of tissues and storage of energy for growth and healing, as well as cope with routine losses and further expenditures related to illness or infections Goals for children include providing adequate nutrition to meet current metabolic demands, as well as for catch-up growth Estimating energy requirements is challenging during critical illness Indirect calorimetry is the gold standard for determining energy needs, although feasibility and availability to implementing indirect calorimetry may limit its use Estimated Nutrition Requirements Special considerations for vitamins and minerals: ■ Vitamin D: Infants receiving exclusive breast milk or less than 1000 mL infant formula daily require additional cholecalciferol 400 units/day ■ Calcium: may have increased losses with use of loop diuretics ■ Potassium: may have increased losses with use of diuretics Mode of Feeding Enteral Nutrition Enteral nutrition is the preferred mode of feeding when gut function is intact Improved nutritional status is directly related to improved surgical outcomes Given the vast literature demonstrating the high incidence of feeding difficulties and growth failure in patients with CHD, there has been growing interest in the development of nutrition protocols to standardize recommendations and decrease provider variability in feeding practices.48 Furthermore, the use of enteral feeding protocols has been shown to be a safe and advantageous process for optimizing nutrient delivery.62–64 The Feeding Work Group of the National Pediatric Cardiology Quality Improvement Collaborative published a comprehensive literature review of best nutrition practices from collaborating centers, with detailed recommendations for standardizing nutrition support and feeding infants with a functionally univentricular heart.60 During the interstage period, there is considerable variation in feeding modality practices, including oral only, oral and tube feeding, or tube feeding only Studies have shown that normal growth may be achieved, regardless of feeding modality, with adequate caloric provision There may be important differences clinically between children able to maintain adequate oral feeding versus those fed via nasogastric or gastric tube The inability to feed orally or achieve adequate growth velocity may be signs of more severe illness.65 For patients who require enteral tube feeding, close nutrition monitoring, evaluation, and intervention are imperative to frequently advance regimens to maintain ageappropriate growth The implementation of interstage home monitoring programs, first introduced by Ghanayem and colleagues at the Children's Hospital of Wisconsin, including daily weight and nutrition intake records, has been associated with improved growth outcomes and survival.65 These practices have had increasing applications worldwide Lack of adjustments to enteral regimens for patients requiring tube feeds can also lead to plateaus in weight gain and growth failure Parenteral Nutrition Although enteral nutrition is the preferred mode of nutrition, it may not always be feasible Adequate nutrient delivery is often still required to offset the catabolic burden resulting from critical illness There is ongoing debate in the literature regarding the macronutrient dosing, the route of delivery, and timing of initiation of parenteral nutrition in critically ill children.66 There is heightened awareness of the complications and side effects of parenteral nutrition, including infection, risks/benefit ratio, and ongoing investigations to determine the optimal timing of nutrition support The landmark study, the Early versus Late Parenteral Nutrition in the Pediatric Intensive Care Unit (PEPaNIC) trial, was a multicenter, prospective, randomized, controlled trial (Netherlands, Belgium, and Canada) involving 1440 critically ill children in the pediatric intensive care unit.67 The trial investigated ... feeding protocols has been shown to be a safe and advantageous process for optimizing nutrient delivery.62–64 The Feeding Work Group of the National Pediatric Cardiology Quality Improvement Collaborative published a comprehensive literature review of best nutrition practices from collaborating... The landmark study, the Early versus Late Parenteral Nutrition in the Pediatric Intensive Care Unit (PEPaNIC) trial, was a multicenter, prospective, randomized, controlled trial (Netherlands, Belgium, and Canada) involving 1440 critically ill children in the pediatric intensive care unit.67 The trial investigated