title: Modular indirect calorimeter suitable for long-term measurements in multipatient intensive care units.
abstract: OBJECTIVE
  The construction of an indirect calorimeter capable of long-term automated sequential monitoring of multiple patients in adult and pediatric ICUs.
  
  
  METHODS
  A prototype system utilizing modular engineering principles, including central respiratory mass spectrometer; validation by organic solvent combustion and nitrogen dilution methods, and Tissot spirometer.
  
  
  METHODS
  Surgical and pediatric ICUs in a tertiary care university hospital.
  
  
  RESULTS
  When expired minute volume was measured over a range of 4 to 28 L in six intubated patients, expired minute volume measured by the prototype system demonstrated a correlation coefficient of .998 compared with simultaneous expired minute volume measured by a Tissot spirometer. Organic solvent combustion demonstrated a maximum error of 3.8% for oxygen consumption (VO2) and an average error of 1.73 +/- 1.25% (SEM). The maximum error for the respiratory quotient was 3.0%, with an average error of 1.75 +/- 1.07%. VO2 (predicted) vs. VO2 (measured) demonstrated a correlation coefficient of .997. Validation with the nitrogen dilution method over a range of FIO2 from 0.21 to 0.60 demonstrated a maximum error of 7.9%, with an average error of -1.72 +/- 1.1% (n = 51).
  
  
  CONCLUSIONS
  Indirect calorimetry by means of a shared system for measurements in multiple patients in ICUs is feasible and cost effective utilizing modular principles and a centralized respiratory gas analyzer.
authors.affiliation: Pediatric Critical Care, University of Minnesota Hospital and Clinic, Minneapolis.
authors.forename: D M
authors.initials: DM
authors.lastname: Steinhorn
authors.forename: A L
authors.initials: AL
authors.lastname: Rozenberg
authors.forename: M J
authors.initials: MJ
authors.lastname: Boyle
authors.forename: J H
authors.initials: JH
authors.lastname: Abrams
authors.forename: R C
authors.initials: RC
authors.lastname: McComb
authors.forename: I
authors.initials: I
authors.lastname: Gilmour
authors.forename: F B
authors.initials: FB
authors.lastname: Cerra
mesh_terms: D000328:Adult; D001784:Blood Gas Analysis / Q000191:economics / Q000295:instrumentation / Q000379:methods; D002138:Calibration; D002153:Calorimetry, Indirect / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D002648:Child; D003362:Cost-Benefit Analysis; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D006801:Humans; D007362:Intensive Care Units; D008838:Microcomputers; D008991:Monitoring, Physiologic / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D015596:Nutrition Assessment; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D012997:Solvents; D013147:Spirometry / Q000191:economics / Q000295:instrumentation* / Q000379:methods
chemical_list: D012997:Solvents