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October 16-20, 2010 San Diego, CA Home Abstract Archive Search Abstracts 2010 Session Grid 2010 Meeting Website Policy Statements ASA Website Feedback 
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A686
October 19, 2008 2:00 PM - 4:00 PM Room Hall E2-Area M, |
| Educational Software for Bispectral Index Simulation |
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Ana Castro, B.S., Eduarda Amadeu, M.D., Paula Sa Couto, M.D., Pedro Amorim, M.D., Catarina S. Nunes, Ph.D. Departamento de Anestesiologia, Hospital Geral de Santo Antonio, Porto, Portugal |
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Background and Goal of Study: With the recent commercialization of Target Controlled Infusion anesthesia, one of the problems encountered by new users is what drug target concentration to choose. Usually anesthesiologists must rely on their experience to decide and adjust the drug's dose for the specific patient, in order to maintain adequate anesthesia throughout the intervention. In previous works [1] we developed a simulation software to help inexperienced TCI users, simulating State Entropy (SEnt) with propofol and remifentanil effect-site concentration steering. The objective of this work is to expand the functionalities of the previous presented software, introducing the simulation of the Bispectral Index (BIS), using average models for the population data. Material and Methods: Data were collected during urological procedures, with TCI anesthesia of remifentanil and propofol (Minto[2] and Schnider[3] PKPD models). Entropy and BIS were monitored, and RugloopII® was used to collect data every 5s. An algorithm was developed to extract the different drug combinations. Each time propofol or remifentanil effect-site concentration targets were changed, a different time interval for analysis was defined. BIS, propofol and remifentanil effect-site concentration values found during these intervals were averaged, and the BIS standard deviation found. With this information, two 3D surfaces were built for the sample (nonlinear least squares regression)[1]: propofol effect-site concentration, remifentanil effect-site concentration and average BIS (Av Surface); propofol effect-site concentration, remifentanil effect-site concentration and BIS standard deviation (SD Surface). MATLAB R2007a was used to adjust the models and build the software user friendly interface. (Data: Mean±SD) Results and Dicussion: Data collected from twenty patients, thirteen male, age 54±14 years, weight 70±14kg, height 166±9cm. Surgeries were: prostatectomy (eight), nefrectomy (five), urether (three), other (four). The data sets provided 312 time periods for analysis. The developed software allows the user to simulate the anesthesia index using propofol and remifentanil effect-site concentration target steering, obtaining average values for BIS (Av Surface). As optional features, the 99% confidence intervals of the simulation can be viewed, and generated disturbances introduced (SD Surface).[figure1]Conclusion: The developed software can be a valuable instrument for inexperienced TCI users, assessing the effect of changes and combinations of propofol and remifentanil effect-site concentration targets on BIS and SEnt. In the future this tool will be developed including other types of surgeries, individual fitted data and other anesthesia indices. References: [1] Euroanaesthesia (accepted); [2] Anesthesiology, 1997, 86:24-33; [3]Anesthesiology, 1998, 88:1170-82 Acknowledgements: Fundacao para a Ciencia e a Tecnologia. Anesthesiology 2008; 109 A686 |
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