title: Laboratory validation of the M-COVX metabolic module in measurement of oxygen uptake.
abstract: A practical method of breath-by-breath monitoring of metabolic gas exchange has previously been developed by GE Healthcare and can now be easily incorporated into existing anaesthetic and critical care monitoring (M-COVX). Previous research using this device has shown good accuracy and precision between the M-COVX measurements and a traditional measurement of gas uptake at the mouth and also against the reverse Fick method during cardiac surgery and critical care, but its accuracy in the paediatric situation and across a range of ventilatory settings awaits validation. We tested the M-COVX metabolic monitor in the laboratory comparing its measurement to a traditional Haldane transformation across a wide range of oxygen consumption values, from 50 ml/minute to just under 300 ml/minute, typical of those expected in anaesthetised adults and children. The M-COVX device showed acceptable accuracy with an overall mean bias of -3.3% (range -15.1 to +4.2%, P = 0.21). Excellent linearity was found, by y = 0.96x + 0.5 ml/minute, r = 0.99. The device showed acceptable robustness to ventilatory changes examined, including changes in respiratory rate, I:E ratio, FiO2 up to 75% and simulated spontaneous breathing. However any induced leak from around the simulated endotracheal tube caused a significant error in paediatric scenarios.
authors.affiliation: Department of Anaesthesia, The Austin Hospital, Heidelberg, Victoria, Australia.
authors.forename: C R
authors.initials: CR
authors.lastname: Stuart-Andrews
authors.forename: P
authors.initials: P
authors.lastname: Peyton
authors.forename: T B
authors.initials: TB
authors.lastname: Walker
authors.forename: A D
authors.initials: AD
authors.lastname: Cairncross
authors.forename: G J B
authors.initials: GJ
authors.lastname: Robinson
authors.forename: B
authors.initials: B
authors.lastname: Lithgow
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000758:Anesthesia / Q000379:methods; D002648:Child; D002675:Child, Preschool; D003422:Critical Care / Q000379:methods; D004867:Equipment Design; D006801:Humans; D007223:Infant; D016343:Monitoring, Intraoperative / Q000295:instrumentation; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange; D015203:Reproducibility of Results; D012121:Respiration, Artificial / Q000379:methods; D055815:Young Adult