Article: H∞ control analysis of patient agitation management in the critically ill Journal: International Journal of Intelligent Systems Technologies and Applications (IJISTA) 2005 Vol.1 No.1/2 pp.111 - 125 Abstract: Patient agitation in the critically ill damages patient health, increases length of stay, and contributes to rising healthcare costs. Recently developed quantifiable measures of patient agitation create the potential for automated sedation management. A physiologically verified non-linear model of agitation-sedation dynamics is used to design and evaluate sedative infusion controllers. A simplified linear model is used for H∞ analysis and control design to minimise the transfer function between unknown stimulus and resulting patient agitation. Regions of stability and instability are identified using H∞ Lyapunov methods, and bolus-based heavy derivative feedback control is shown to best minimise the H∞ norm. H∞ controllers yield an approximately 25% improvement over prior choices, and a nearly 50% improvement over current clinical practice. Importantly, these results show that general trends in the linear system are still reflected. Inderscience Publishers - linking academia, business and industry through research

Title: H∞ control analysis of patient agitation management in the critically ill

Authors: J. Geoffrey Chase, Andrew D. Rudge, Dominic S. Lee, Geoffrey M. Shaw

Addresses: Department of Mechanical Engineering, Centre for Bioengineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. ' Department of Mechanical Engineering, Centre for Bioengineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. ' Department of Mathematics and Statistics, Centre for Bioengineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. ' Department of Intensive Care Medicine, Christchurch Hospital, Christchurch, New Zealand

Abstract: Patient agitation in the critically ill damages patient health, increases length of stay, and contributes to rising healthcare costs. Recently developed quantifiable measures of patient agitation create the potential for automated sedation management. A physiologically verified non-linear model of agitation-sedation dynamics is used to design and evaluate sedative infusion controllers. A simplified linear model is used for H∞ analysis and control design to minimise the transfer function between unknown stimulus and resulting patient agitation. Regions of stability and instability are identified using H∞ Lyapunov methods, and bolus-based heavy derivative feedback control is shown to best minimise the H∞ norm. H∞ controllers yield an approximately 25% improvement over prior choices, and a nearly 50% improvement over current clinical practice. Importantly, these results show that general trends in the linear system are still reflected.

Keywords: biomedical modelling; sedative infusion control; H∞ control; patient agitation management; critically ill patients; healthcare; automated sedation management; biomechatronics; bioengineering.

DOI: 10.1504/IJISTA.2005.007310

International Journal of Intelligent Systems Technologies and Applications, 2005 Vol.1 No.1/2, pp.111 - 125

Published online: 05 Jul 2005 *

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Title: H∞ control analysis of patient agitation management in the critically ill

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