title: Accuracy of the Foldes-Biro equation for measurement of oxygen uptake during anaesthesia: a laboratory simulation.
abstract: Laboratory benchtop testing was conducted of the Biro method for measurement of oxygen uptake from an anaesthetic breathing system by patients during low flow anaesthesia. A high precision flow and gas concentration measurement system was employed in conjunction with a physical gas exchange simulation model to test the theoretical basis of the method under controlled conditions. Simulated oxygen uptake values between 200 and 350 ml x min(-1) were modelled. The Biro-derived measurement of simulated O(2) uptake significantly underestimated the target value (mean difference -88.5 ml x min(-1), or -31.7%). The bias was directly proportional to the simulated O(2) uptake. The Biro method has a systematic bias that cannot be explained by random measurement imprecision.
authors.affiliation: Department of Electrical and Computer Systems Engineering, Faculty of Engineering, Monash University Centre for Biomedical Engineering, Victoria, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Stuart-Andrews
authors.forename: P
authors.initials: P
authors.lastname: Peyton
authors.forename: G
authors.initials: G
authors.lastname: Robinson
authors.forename: B
authors.initials: B
authors.lastname: Lithgow
mesh_terms: D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D004334:Drug Administration Schedule; D006801:Humans; D008954:Models, Biological; D008961:Models, Structural; D016343:Monitoring, Intraoperative / Q000379:methods*; D010100:Oxygen / Q000008:administration & dosage; D010101:Oxygen Consumption
chemical_list: D018685:Anesthetics, Inhalation; D010100:Oxygen