Continuous indirect calorimetry--a laboratory simulation of a new method for non-invasive metabolic monitoring of patients under anaesthesia or in critical care.
A method was tested which permits continuous real time monitoring of O(2) uptake in patients attached to a breathing system. The method is an indirect calorimetry technique which uses fresh gas rotameters for control, regulation and measurement of the gas flows into the system, with continuous sampling of mixed exhaust gas. Testing of this approach was conducted using a lung gas exchange simulator, in order to determine its accuracy and precision under controlled conditions, when compared to a range of simulated O(2) uptake values. The overall mean bias (standard error) was -1.3 mL min(-1) (0.3) and the standard deviation was 6.5. The performance of the method was found to be consistent across a wide range of fresh gas flow rates and O(2) concentrations from 30 to 80%. The method warrants in vivo testing under clinical conditions.
Stuart-Andrews
Christopher
C
Department of Electrical and Computer Systems Engineering, Faculty of Engineering, Monash University, Victoria, Australia. christopher-stuart-andrews@eng.monash.edu.au
Peyton
Philip
P
Robinson
Gavin
G
Lithgow
Brian
B
D002151:Calorimetry / Q000379:methods*; D003422:Critical Care / Q000379:methods*; D006801:Humans; D008954:Models, Biological; D008991:Monitoring, Physiologic / Q000379:methods*; D010101:Oxygen Consumption / Q000502:physiology