title: Systematic review of the influence of energy and protein intake on protein balance in critically ill children.
abstract: OBJECTIVE
  To examine the influence of protein and energy intakes on protein balance in children receiving mechanical ventilation in the pediatric intensive care unit.
  
  
  METHODS
  We hypothesized that higher energy and protein intakes are correlated with positive protein balance. We performed a systematic literature search to identify studies reporting protein balance in children requiring mechanical ventilation. Factors contributing to protein balance, including protein and energy intake, age, illness severity, study design, and feeding routes, were analyzed using a qualitative approach.
  
  
  RESULTS
  Nine studies met the entry criteria and were included in the final analysis. Positive nitrogen balance was reported in 6 of the studies, with a wide range of associated energy and protein intakes. Measures of central tendency for daily energy and protein intakes were significantly correlated with positive protein balance. A minimum intake of 57 kcal/kg/day and 1.5 g protein/kg/day were required to achieve positive protein balance.
  
  
  CONCLUSIONS
  We found a correlation between higher energy and protein intakes and achievement of positive protein balance in children receiving mechanical ventilation in the pediatric intensive care unit. However, there is a paucity of interventional studies, and a variety of protocols have been used to determine nitrogen balance. Larger clinical trials with uniform methodology are needed to further examine the effect of energy and protein intake on protein balance, lean body mass, and clinical outcomes in children on mechanical ventilation.
authors.affiliation: Division of Gastroenterology, Children's Hospital Boston, Boston, MA 02115, USA. lori.bechard@childrens.harvard.edu
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Bechard
authors.forename: J Scott
authors.initials: JS
authors.lastname: Parrott
authors.forename: Nilesh M
authors.initials: NM
authors.lastname: Mehta
mesh_terms: D002648:Child; D016638:Critical Illness; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D004734:Energy Metabolism; D004750:Enteral Nutrition; D006801:Humans; D015278:Intensive Care Units, Pediatric; D009584:Nitrogen / Q000378:metabolism; D010288:Parenteral Nutrition; D011506:Proteins / Q000378:metabolism*; D012121:Respiration, Artificial
chemical_list: D004044:Dietary Proteins; D011506:Proteins; D009584:Nitrogen