title: Accuracy of Oxygen Consumption and Carbon Dioxide Elimination Measurements in 2 Breath-by-Breath Devices.
abstract: BACKGROUND
  Although accurate quantification of oxygen consumption (V̇O2) and carbon dioxide elimination (V̇CO2) provides important insights into a patient's nutritional and hemodynamic status, few devices exist to accurately measure these parameters in children. Therefore, we assessed the accuracy and agreement of 2 devices currently on the market using a pediatric in vitro model of gas exchange.
  
  
  METHODS
  We utilized a Huszczuk simulation model, which simulates oxygen consumption and carbon dioxide production using gas dilution, to examine the accuracy of two FDA-cleared respiratory modules (E-COVX and E-sCAiOVX-00). V̇O2and V̇CO2were set at 20, 40, 60, and 100 mL/min, ranges typical for infant and pediatric patients. Bland-Altman analysis was used to calculate the bias and limits of agreement of each device relative to simulated values for V̇O2and V̇CO2.
  
  
  RESULTS
  The E-COVX mean percentage bias (limits of agreement) was -26.3% (-36.1 to -16.6%) and -39.3% (-47.5 to -31.1%) for V̇O2and V̇CO2, respectively. The mean bias (limits of agreement) for the E-aCAiOVX-00 was -0.5% (-13.3 to 12.3%) and -6.0% (-13.8 to 1.7%) for V̇O2and V̇CO2, respectively.
  
  
  CONCLUSIONS
  The E-COVX demonstrated bias and limits of agreement that were not clinically acceptable; therefore, application of this module to pediatric patients would not be recommended. The new module, E-sCAiOVX, demonstrated acceptable bias and limits of agreement for the V̇O2and V̇CO2in the range 40-100 mL/min (which corresponds to patients in the range of ∼5-16 kg).
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine craig.smallwood@childrens.harvard.edu.|Harvard Medical School, Boston, Massachusetts.
authors.forename: Craig D
authors.initials: CD
authors.lastname: Smallwood
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: John N
authors.initials: JN
authors.lastname: Kheir
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine.|Harvard Medical School, Boston, Massachusetts.
authors.forename: Brian K
authors.initials: BK
authors.lastname: Walsh
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine.|Harvard Medical School, Boston, Massachusetts.
authors.forename: Nilesh M
authors.initials: NM
authors.lastname: Mehta
mesh_terms: D001944:Breath Tests / Q000295:instrumentation*; D019296:Capnography / Q000295:instrumentation*; D002245:Carbon Dioxide / Q000032:analysis*; D002648:Child; D003198:Computer Simulation; D006801:Humans; D007223:Infant; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D012121:Respiration, Artificial / Q000295:instrumentation*
chemical_list: D002245:Carbon Dioxide
keywords: accuracy; carbon dioxide elimination; gas exchange; indirect calorimetry; oxygen consumption