title: Indirect Calorimetry in Mechanically Ventilated Patients: A Prospective, Randomized, Clinical Validation of 2 Devices Against a Gold Standard.
abstract: The 2 currently available indirect calorimeters, CCM Express Indirect Calorimeter (MedGraphics, St Paul, MN) and Quark RMR ICU Indirect Calorimeter (COSMED, Rome, Italy), have not been validated against a gold standard in mechanically ventilated patients. Our aim was to do so using a gold-standard, modified Tissot bell-spirometer method in mechanically ventilated patients who were hemodynamically, respiratory, and metabolically stable.
  
  
  
  We studied 30 patients undergoing general anesthesia and major gynecological surgery. We measured oxygen consumption ([Formula: see text]O2) and resting energy expenditure (REE) in a randomized, sequential, crossover design with double determination of each device.
  
  
  
  Compared with the modified Tissot bell-spirometer, the CCM Express Indirect Calorimeter demonstrated a mean Δ-REE of +361 kcal/d, corresponding to a 31% overestimation of energy requirements. Bland-Altman analysis for REE showed a mean (SD) bias of 384 (124) with limits of agreement 142-627 kcal/d. QUARK RMR ICU demonstrated a mean Δ-REE of 81 kcal/d, corresponding to a 7% overestimation of energy requirements. Bland-Altman plot analysis showed a mean (SD) bias of 77 (167) with limits of agreement -249 to 404 kcal/d.
  
  
  
  The QUARK RMR ICU Indirect Calorimeter compared better with the gold standard for values of [Formula: see text]O2and REE than did the CCM Express Indirect Calorimeter in mechanically ventilated patients who were circulatory and respiratory stable. Both indirect calorimeters had low precision.
authors.affiliation: 1 Department of Intensive Care, Copenhagen University Hospital, Rigshospitalet, Denmark.
authors.forename: Matilde Jo
authors.initials: MJ
authors.lastname: Allingstrup
authors.affiliation: 2 Department of Clinical Nutrition, Copenhagen University Hospital, Rigshospitalet, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Kondrup
authors.affiliation: 1 Department of Intensive Care, Copenhagen University Hospital, Rigshospitalet, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Perner
authors.affiliation: 3 Department of Anaesthesiology, Bispebjerg Hospital, Denmark.
authors.forename: Poul Lunau
authors.initials: PL
authors.lastname: Christensen
authors.affiliation: 1 Department of Intensive Care, Copenhagen University Hospital, Rigshospitalet, Denmark.
authors.forename: Tom Hartvig
authors.initials: TH
authors.lastname: Jensen
authors.affiliation: 4 Department of Anaesthesiology, Copenhagen University Hospital, Rigshospitalet, Denmark.
authors.forename: Steen Winther
authors.initials: SW
authors.lastname: Henneberg
mesh_terms: D000328:Adult; D000368:Aged; D001481:Basal Metabolism; D002153:Calorimetry, Indirect / Q000295:instrumentation*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007558:Italy; D008297:Male; D008875:Middle Aged; D009751:Nutritional Requirements; D010101:Oxygen Consumption; D011446:Prospective Studies; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D018401:Sample Size
keywords: indirect calorimetry; intensive care; mechanical ventilation; oxygen consumption; resting energy expenditure (REE); validation