Intelligent alarms in anesthesia : a real time expert system application Citation for published version (APA): Aa, van der, J. L. C. M. (1990). Intelligent alarms in anesthesia : a real time expert system application. [Phd Thesis 1 (Research TU/e / Graduation TU/e), Electrical Engineering]. Technische Universiteit Eindhoven. https://doi.org/10.6100/IR330395 DOI: 10.6100/IR330395 Document status and date: Published: 01/01/1990 Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. 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If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Download date: 30. Jan. 2023 INTELLIGENTAlARMS IN ANESTHESIA a real time expert system application CIP-GEGEVENS KONINKLIJKE BIBLIOTHEEK, DEN HAAG Aa, Johannes Jacobus Leonardus Catherina Maria van der Intelligent alarms in anesthesia: a real time expertsystem application / Johannes Jacobus Leonardus Catherina Maria van der Aa. - [S.l. : s.n.]. - Fig., tab. Proefschrift Eindhoven. - Met lit. opg., reg. ISBN 90-9003303-3 SISO 608.1 UDC 616-089.5(043.3) NUGI 742 Trefw: anesthesie; patientbewaking / expertsystemen INTELLIGENT ALARMS IN ANESTHESIA a real time expert system application PROEFSCHRIFf ter verkrijging van de graad van doctor aan de Technische Universiteit Eindhoven, op gezag van de Rector Magnificus, prof. ir. M. Tels, voor een commissie aangewezen door het College van Dekanen in het openbaar te verdedigen op vrijdag 11 mei 1990 te 16.00 uur door Johannes Jacobus Leonardus Catherina Maria van der Aa geboren te Aarle-Rixtel (NB) Dit proefschrift is goedgekeurd door de promotoren: Prof. dr. ir. Jan E. W. Beneken en Prof. Joachim S. Gravenstein M.D., Dr. h.c. (Dniversity of Florida) The work reported in this dissertation on the "IntelligentAlarms Project" is the result of a collaboration between the Department of Anesthesiology at the University of Florida (Chairman: Prof. Jerome H. Modell M.D.) in Gainesville, Florida and the Division of Medical Electrical Engineering (Chairman: Prof. dr. Jan E. W. Beneken) from the Eindhoven University ofTechnology in Eindhoven, the Netherlands. The project was supported in part by Ohmeda, a division of The BOC Group Inc. ''And at night you will look up at the stars. Where I live everything is so small that I cannot showyou where my staris to befound. It is betterlike that. My star will bejust one of the stars for you. And so you will love to watch all the stars in the heavellS...." Antoine de Saint Exupery The Little Prince In memory of Ans ACKNOWLEDGEMENTS The research described in this dissertation is the result ofan intense collaboration with numerous persons having made significant contributions. Professor Beneken, your guidance, support, in depth discussions, suggestions, and the many constructive remarks during your many visits to our Gainesville crew made it all possible. For many wonderful years, thank you. Professor Gravenstein, ten years ago you offered me the opportunity to come to Gainesville and work in your group. Thankyou for that opportunity. In these ten years you have taught me so many invaluable things; you supported, encouraged, and guided me towhere I am today. Withoutyou, this research and many other projects would not have been possible. Moreover, as domain expert, your input was essential. Additional clinical knowledge was provided by a great team of enthusiastic anesthesiologists: Drs. Jeff Feldman, Gordon Gibby, Mike Good, Peter Pan, and David Paulus. Thank you for your help and support. Hans Blom, you gave the project the SIMPLEXYS toolbox to convert our ideas into prototypes. Despite the distance between Gainesville and Eindhoven the collaboration was exemplary. Many graduate students have worked on the "Intelligent Alarm" project: Bert de Vries, Rob Bastings, Hans van Oostrom, Jelle Nederstigt, Seong Choi, Chieteuk Abn, Frank Gomez, and John Noll. Their valuable contributions are acknowledged and very much appreciated. My thank goes out to the entire Department ofAnesthesiology at the University ofFlorida and its chairman Dr. Jerome H. Modell M.D., for their interest, support, help, and for allowing me to use the laboratory and various other facilities. IngridMellone,whoread andeditedearlydrafts ofthisdissertation, andDr.David Pharies thank you for your editorial assistance and valuable suggestions. To my wife Ria, for countless reasons, I am indebted. Acknowledgements ii CONTENTS ACKNO~DGEMENTS CONTENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ii 1. INTRODUCTION 1 1.1. Background 1 1.2. Project Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 5 1.3. Chapter Outline 5 2. ANESTHESIA ISSUES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 2.1. General Anesthesia .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 2.2. Anesthesia Equipment and Stages during Anesthesia 8 2.2.1. The Endotracheal Tube. .. . . . . . . . . . . . . . . . . . . . . . .. 8 2.2.2. The Anesthesia Machine ..... . . . . . . . . . . . . . . . . . . ., 9 2.2.3. The Anesthesia Breathing System 10 2.2.4. The Anesthesia Ventilator . . . . . . . . . .. 11 2.3. The Circle Breathing Circuit .. . . . . . . . . . . . . . . . . . . . . . . . . .. 13 3. MONITORING DURING ANESTHESIA . . . . . . . . . . . . . . . . . . . . . . . .. 17 3.1. Why Monitor , 17 3.2. What to Monitor 19 3.3. How often to Monitor . . . . . . . . . . . . . . . . . . .. 22 3.4. How to Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23 3.4.1. Monitoring Oxygenation. . . . . . . . . . . . . . . . . . . . . . . . .. 24 3.4.2. Monitoring Ventilation 25 3.4.3. Monitoring Circulation 26 3.4.4. Monitoring Temperature 27 3.4.5. Monitoring the Neuromuscular Junction 27 3.4.6. Vigilance 27 3.4.7. Preoperative Information . . . . . . . . . . . . . . . . . . . . . . . .. 28 3.5. Signal Processing and Data Presentation 28 4. ALARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 31 4.1. Current Alarm Technology 31 4.2. Possible Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33 4.2.1. Dealing with Artifact 34 4.2.2. Trend Detection 34 4.2.3. Multi-Variable Tactics. . . . . . . . . . . . . . . . . . . . . . . . . .. 34 4.2.4. Integration and Communication . . . . . . . . . . . . . . . . . . . ., 35 Contents iii 4.3. Toward Intelligent Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35 4.3.1. Fantasy or Possibility? . . . . . . . . . . . . . . . . . . . . . . . . . .. 36 4.3.2. The Layered Approach . . . . . . . . . . . . . . . . . . . . . . . . .. 38 4.4. Limits and Alarms " 41 5. IMPLEMENTING INTELLIGENT ALARMS . . . . . . . . . . . . . . .. 42 5.1. Monitoring for Patient Safety 42 5.1.1. Detecting Potential Problems 42 5.1.2. The Differential Diagnosis . . . . . . . . . . . . . . . . . . . .. 43 5.1.3. Implications and Treatment 45 5.2. Selecting the Area of Implementation . . . . . . . . . . . . . . . .. 46 5.2.1. The Major Cause of Injury 46 5.2.2. Suggested Improvements 47 5.2.3. Scope of the Project . . . . . . . . . . . . . . . . . . . . . . . . . . .. 47 5.3. Project Approach 48 5.3.2. Possible Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49 5.3.3. The Expert Systems Approach 50 6. EXPERT SYSTEMS 52 6.1. Introduction to Expert Systems 53 6.1.1. Expert System Components 53 6.1.2. Building an Expert System . . . . . . . . . . . . . . . . . . . . . . .. 56 6.2. Expert Systems Applications in Medicine . . . . . . . . . . . . . . . . . . .. 57 6.3. Finding an Expert System Tool for Intelligent Alarms 58 6.4. The Expert System Tool: SIMPLEXYS . . . . . . . . . . . . . . . . .. 60 6.4.1. Introduction 60 6.4.2. Building Applications with SIMPLEXYS . . . . . . . . . . . . . .. 61 6.4.3. SIMPLEXYS Rules 62 6.4.4. SIMPLEXYS Programs . . . . . . . . . . . . . . . . . . . . . . . . .. 64 6.5. SIMPLEXYS and the Intelligent Alarm Project Requirements 71 6.5.1. Real Time Performance 71 6.5.2. Linkage with Other Software 72 6.5.3. Temporal Reasoning. . . . . . . . . . . . . . . . . . . . . . . . . . .. 72 7. IMPLEMENTATION: PROTOTYPE I 74 7.1. Knowledge Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 75 7.1.1. Breathing System Problems 75 7.1.2. Monitoring the Breathing System. . . . . . . . . . . . . . . . . . .. 77 7.1.3. Summary 79 7.2. From Knowledge to Signals. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 79 Contents