Table Of ContentGuide to health informatics
This page intentionally left blank
Guide to health informatics
Second edition
Enrico Coiera
Professor and Foundation Chair of Medical Informatics,
University of New South Wales, Sydney, Australia
Hodder Arnold
AMEMBER OF THE HODDER HEADLINE GROUP
First published in Great Britain in 2003 by
Hodder Arnold, a member of the Hodder Headline Group,
338 Euston Road, London NW1 3BH
http://www.hoddereducation.com
Distributed in the United States of America by
Oxford University Press Inc.,
198 Madison Avenue, New York, NY10016
Oxford is a registered trademark of Oxford University Press
© 2003 Enrico Coiera
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any
means, electronically or mechanically, including photocopying, recording or any information storage or
retrieval system, without either prior permission in writing from the publisher or a licence permitting restricted
copying. In the United Kingdom such licences are issued by the Copyright Licensing Agency: 90 Tottenham
Court Road, London W1T 4LP.
Whilst the advice and information in this book are believed to be true and accurate at the date of going to
press, neither the author nor the publisher can accept any legal responsibility or liability for any errors or
omissions that may be made. In particular (but without limiting the generality of the preceding disclaimer)
every effort has been made to check drug dosages; however it is still possible that errors have been missed.
Furthermore, dosage schedules are constantly being revised and new side-effects recognized. For these
reasons the reader is strongly urged to consult the drug companies’ printed instructions before administering
any of the drugs recommended in this book.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
Library of Congress Cataloging-in-Publication Data
A catalog record for this book is available from the Library of Congress
ISBN-10: 0 340 76425 2
ISBN-13: 978 0 340 76425 1
2 3 4 5 6 7 8 9 10
Commissioning Editor: Georgina Bentliff
Development Editor: Heather Smith
Project Editor: Zelah Pengilley
Production Controller: Lindsay Smith
Cover Design: Amina Dudhia
Typeset in 10/13pt Minion by Charon Tec Pvt. Ltd, Chennai, India
Printed and bound in India
What do you think about this book? Or any other Hodder Arnold title?
Please send your comments to www.hoddereducation.com
Contents
Note xiii
Preface xiv
Preface to the first edition xvi
Acknowledgements xviii
Publishers’ acknowledgements xx
Introduction to health informatics xxi
PART 1 BASIC CONCEPTS IN INFORMATICS
1 Models 3
1.1 Models are abstractions of the real world 4
1.2 Models can be used as templates 7
1.3 The way we model the world influences the way we affect the world 9
Conclusions 10
Discussion points 11
2 Information 12
2.1 Information is inferred from data and knowledge 12
2.2 Models are built from symbols 13
2.3 Inferences are drawn when data are interpreted according to a model 14
2.4 Assumptions in a model define the limits to knowledge 16
2.5 Computational models permit the automation of data interpretation 18
Conclusions 20
Discussion points 20
3 Information systems 22
3.1 A system is a set of interacting components 22
3.2 A system has an internal structure that transforms inputs into outputs for a
specific purpose 23
vi CONTENTS
3.3 Information systems contain data and models 29
Conclusions 31
Discussion points 31
PART 2 INFORMATICS SKILLS
4 Communicating 35
4.1 The structure of a message determines how it will be understood 36
4.2 The message that is sent may not be the message that is received 37
4.3 Grice’s conversational maxims provide a set of rules for conducting
message exchanges 41
Conclusions 42
Discussion points 42
5 Structuring 44
5.1 Messages are structured to achieve a specific task using available resources
to suit the needs of the receiver 44
5.2 The patient record can have many different structures 49
Conclusions 53
Discussion points 53
6 Questioning 55
6.1 Clinicians have many gaps and inconsistencies in their clinical knowledge 56
6.2 Well-formed questions seek answers that will have a direct impact on
clinical care 59
6.3 Questions to computer knowledge sources are structured according to the
rules of logic 60
6.4 Well-formed questions are both accurate and specific 62
Conclusions 65
Discussion points 65
7 Searching 66
7.1 Successful searching for knowledge requires well-structured questions
to be asked of well-informed agents 66
7.2 Search strategies are optimized to minimize cost and maximize benefit 67
7.3 The set of all possible options forms a search space 68
7.4 Search strategies are designed to find the answer in the fewest possible steps 69
7.5 The answer is evaluated to see if it is well formed, specific, accurate and reliable 77
Conclusions 79
Discussion points 79
CONTENTS vii
8 Making decisions 81
8.1 Problem-solving is reasoning from the facts to create alternatives, and then
choosing one alternative 81
8.2 Hypotheses are generated by making inferences from the given data 83
8.3 Decision trees can be used to determine the most likely outcome when
there are several alternatives 88
8.4 Heuristic reasoning guides most clinical decisions but is prone to biases and
limited by cognitive resources 89
8.5 An individual’s preferences for one outcome over another can be
represented mathematically as a utility 93
Conclusions 96
Discussion points 97
PART 3 INFORMATION SYSTEMS IN HEALTHCARE
9 Information management systems 101
9.1 Information systems are designed to manage activities 101
9.2 There are three distinct information management loops 103
9.3 Formal and informal information systems 105
Discussion points 109
10 The electronic medical record 111
10.1 The EMR is not a simple replacement of the paper record 112
10.2 The paper-based medical record 113
10.3 The EMR 117
Conclusions 122
Discussion points 123
11 Designing and evaluating information systems 124
11.1 Design and evaluation are linked processes 125
11.2 The formative assessment cycle defines clinical needs 128
11.3 Summative evaluations attempt to determine the measurable impact
of a system once it is in routine use 129
11.4 Interaction design focuses on the way people interact with technology 130
11.5 Designing for change 134
11.6 Designing the information management cycle 136
Discussion points 139
viii CONTENTS
PART 4 PROTOCOL-BASED SYSTEMS
12 Protocols and evidence-based healthcare 143
12.1 Protocols 145
12.2 The structure of protocols 148
12.3 Care pathways 150
12.4 The protocol life cycle 151
12.5 Departures from a protocol help drive protocol refinement 152
12.6 The application of protocols 153
Discussion points 154
13 Computer-based protocol systems in healthcare 156
13.1 Passive protocol systems 156
13.2 Active protocol systems 158
13.3 Protocol representations and languages 164
Conclusions 169
Discussion points 169
14 Disseminating and applying protocols 171
14.1 The uptake of clinical guidelines will remain low as long as the costs
perceived by clinicians outweigh the benefits 172
14.2 The clinical impact of a guideline is determined both by its efficacy
as well as its adoption rate 173
14.3 Strategies for improving the uptake of evidence into practice may alter
either actual or perceived costs and benefits 174
14.4 Socio-technical barriers limit the use of evidence in clinical settings 178
Discussion points 178
15 Designing protocols 180
15.1 Protocol construction and maintenance 180
15.2 The design of protocols 183
15.3 Protocol design principles 185
Discussion points 187
PART 5 LANGUAGE, CODING AND CLASSIFICATION
16 Terms, codes and classification 191
16.1 Language establishes a common ground 191
16.2 Common terms are needed to permit assessment of clinical activities 192
CONTENTS ix
16.3 Terms, codes, groups and hierarchies 193
16.4 Compositional terminologies create complicated concepts
from simple terms 196
16.5 Using coding systems 197
Discussion points 200
17 Healthcare terminologies and classification systems 201
17.1 The International Classification of Diseases 202
17.2 Diagnosis related groups 205
17.3 Read codes 206
17.4 SNOMED 208
17.5 SNOMED Clinical Terms 210
17.6 The Unified Medical Language System (UMLS) 213
17.7 Comparing coding systems is not easy 215
Discussion points 216
18 The trouble with coding 217
18.1 Universal terminological systems are impossible to build 218
18.2 Building and maintaining terminologies is similar to software engineering 222
18.3 Compositional terminologies may be easier to maintain over time despite
higher initial building costs 223
18.4 The way forward 226
Discussion points 228
PART 6 COMMUNICATION SYSTEMS IN HEALTHCARE
19 Communication system basics 231
19.1 The communication space accounts for the bulk of information
transactions in healthcare 232
19.2 A communication system includes people, messages, mediating
technologies and organizational structures 233
19.3 Shared time or space defines the basic contexts of communication
system use 236
19.4 Communication services 239
Conclusions 242
Discussion points 242
20 Communication technology 244
20.1 Machine communication is governed by a set of layered protocols 244
20.2 Communication channels can be dedicated or shared 246
