title: Prevalence of Underprescription or Overprescription of Energy Needs in Critically Ill Mechanically Ventilated Adults as Determined by Indirect Calorimetry: A Systematic Literature Review.
abstract: BACKGROUND
  Underfeeding and overfeeding has been associated with adverse patient outcomes. Resting energy expenditure can be measured using indirect calorimetry. In its absence, predictive equations are used. A systematic literature review was conducted to determine the prevalence of underprescription and overprescription of energy needs in adult mechanically ventilated critically ill patients by comparing predictive equations to indirect calorimetry measurements.
  
  
  METHODS
  Ovid MEDLINE, CINAHL Plus, Scopus, and EMBASE databases were searched in May 2013 to identify studies that used both predictive equations and indirect calorimetry to determine energy expenditure. Reference lists of included publications were also searched. The number of predictive equations that underestimated or overestimated energy expenditure by ±10% when compared to indirect calorimetry measurements were noted at both an individual and group level.
  
  
  RESULTS
  In total, 2349 publications were retrieved, with 18 studies included. Of the 160 variations of 13 predictive equations reviewed at a group level, 38% underestimated and 12% overestimated energy expenditure by more than 10%. The remaining 50% of equations estimated energy expenditure to within ±10 of indirect calorimetry measurements. On an individual patient level, predictive equations underestimated and overestimated energy expenditure in 13-90% and 0-88% of patients, respectively. Differences of up to 43% below and 66% above indirect calorimetry values were observed.
  
  
  CONCLUSIONS
  Large discrepancies exist between predictive equation estimates and indirect calorimetry measurements in individuals and groups. Further research is needed to determine the influence of indirect calorimetry and predictive equation limitations in contributing to these observed differences.
authors.affiliation: Nutrition and Dietetics Department, The Alfred, Melbourne Victoria, Australia Department of Nutrition and Dietetics, Monash University, Notting Hill Victoria, Australia O.Tatucu@alfred.org.au.
authors.forename: Oana A
authors.initials: OA
authors.lastname: Tatucu-Babet
authors.affiliation: Nutrition and Dietetics Department, The Alfred, Melbourne Victoria, Australia Australian and New Zealand Intensive Care Research Centre (ANZIC-RC), Department of Epidemiology and Preventive Medicine, Monash University, Melbourne Victoria, Australia.
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Ridley
authors.affiliation: Nutrition and Dietetics Department, The Alfred, Melbourne Victoria, Australia Department of Dietetics and Human Nutrition, La Trobe University, Bundoora Victoria, Australia.
authors.forename: Audrey C
authors.initials: AC
authors.lastname: Tierney
mesh_terms: D002153:Calorimetry, Indirect; D016638:Critical Illness / Q000628:therapy*; D002149:Energy Intake; D004734:Energy Metabolism; D006801:Humans; D009751:Nutritional Requirements; D018529:Nutritional Support / Q000379:methods*; D015995:Prevalence; D016032:Randomized Controlled Trials as Topic; D012121:Respiration, Artificial
keywords: critically ill, nutrition; indirect calorimetry; intensive care unit; predictive equations; resting energy expenditure