title: Model-based administration of inhalation anaesthesia. 2. Exploring the system model.
abstract: We explored our model by displaying its new capabilities, testing its sensitivity to variations in input data and illustrating its use. Its multiple-gas character allows simulation of the mechanisms governing concentration and second gas effects. Simulating the volume of a standing bellows makes it possible to test algorithms for automated closed-circuit anaesthesia. Using desflurane, the model's sensitivity to changes in blood/gas partition coefficient (range 0.42-0.576), cardiac output and minute ventilation was analysed. The model was very sensitive to changes in blood solubility; other results agreed with those reported previously. An alveolar isoflurane tension of 1% atm was rapidly attained and maintained, even using 0.5 litres min(-1) of fresh gas, when isoflurane was 'co-administered' through a vaporizer set to 3.5 vol% and a single aliquot (1.25 ml liquid) injected into the expiratory limb. As a result of its credibility and capabilities, the model is to be tested in the clinical setting.
authors.affiliation: Institute for Anaesthesiology, University of Nijmegen, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: Lerou
authors.forename: L H
authors.initials: LH
authors.lastname: Booij
mesh_terms: D000465:Algorithms; D000764:Anesthesia, Closed-Circuit; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000187:drug effects; D000077335:Desflurane; D006801:Humans; D007530:Isoflurane / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D008954:Models, Biological; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D012680:Sensitivity and Specificity
chemical_list: D018685:Anesthetics, Inhalation; D002245:Carbon Dioxide; D000077335:Desflurane; D007530:Isoflurane; D010100:Oxygen