Nutrition in Clinical Practice Volume XX Number X Month 201X 1 –10 © 2014 American Society for Parenteral and Enteral

hosted at online.sagepub.com Invited Review The metabolic response to illness, injury, or surgery was first described more than 80 years ago in orthopedic patients by Sir David Cuthbertson.1 This response is driven by complex neu-roendocrine pathways and affects macronutrient substrate metabolism. Delivery of adequate nutrients during illness to counteract the metabolic stress response and facilitate healing and tissue repair is an important goal in the care of critically ill children. While a variety of equations have been used to esti-mate energy requirements, these are generally inaccurate in critically ill patients. To prevent unintended underfeeding or overfeeding due to reliance on standard equations, methods to accurately measure energy expenditure during critical illnes