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Clinical Decision Support Systems in
Biomedical Informatics
and their Limitations
Alberto De la Rosa Algarín
Computer Science & Engineering
University of Connecticut, Storrs
alberto.delarosa.algarin@engr.uconn.edu
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Overview
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Clinical Decisions
 What types of clinical decisions exist?
 Requirements for excellent decision-making
 Definition of Decision Support Systems
History
 First possibility of a CDSS
 First prototype and the shortcomings
 Better CDSS (MYCIN, HELP, Leeds System)
Existing Systems
 Pathfinder, Iliad, DiagnosisPro, CKS, HDP, etc.
Limitations
 Patient’s Role, Usability (and performance),
Knowledge sharing and maintenance and Security
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Clinical Decisions
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Two types of clinical decisions:
 Diagnosis decisions
 Diagnosis process
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Diagnosis decisions
 Done analyzing to determine the cause of sickness
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Diagnosis process
 Used to determine which questions to ask in order
to make better diagnosis decisions
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Requirements for excellent decision-making
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Accurate data:
 Bad data is useless obviously
 Good data is equally useless if there is no
knowledge on how to apply it.
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Pertinent knowledge
 The overload of information affects the process of
decision making in a negative way.
 Overload of information can be seen in the ICU
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Appropriate problem-solving skills
 The glue between the correct use of accurate and
pertinent knowledge.
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Goal
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The goal of clinical decision support systems (CDSS)
is to emulate the clinician’s thought process during
diagnosis.
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Definition of Decision Support Systems
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A decision support system is a system in which one or
more computers and computer programs assist in
decision making by providing information.
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They can exist as hardware-software solutions or stand
alone software applications.
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History
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The possibility first appeared in 1959 [Ledley &
Lusted]
 With the use of symbolic logic, probability theory
and value theory, the foundations of medical
diagnosis could be understood.
The first prototype appeared in 1964 [Walker et al.]
 Issues with logistics, scientific shortcomings
related to medical diagnosis, and the lack of
integration to the workflow made the widespread
use and adoption virtually impossible.
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History
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After this, several CDSS appeared that tackled the
previous pitfalls (MYCIN, Leeds System and HELP)
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MYCIN [Shortliffe, 1976]
 A consultation system for patients with infections
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Leeds Abdominal Pain System [De Dombal et al.,
1972]
 A system for the diagnosis of acute abdominal pain
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HELP [Warner, 1979]
 A system to alert clinicians in case of
abnormalities in patient records
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Types
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Management Systems
Provide an environment for the storage and
retrieval of information.
Decision is left to the clinician.
Focusing
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Attention Systems
Alert clinicians when a conflict arises.
Follow simple logic.
Patient-specific
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Recommendation Systems
Offer advice to a single patient using the patient’s
medical history.
Can use simple logic, decision theory, cost-benefit
analysis, etc.
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Requirements of a CDSS
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Clinical decision support systems must satisfy the
following requirements in order to be widely accepted
and used:
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Patient Data Acquisition and Validation
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Medical Knowledge Modeling, Elicitation,
Representation and Reasoning
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System Performance
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Integration to the Workflow
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Requirements: Patient Data Acquisition
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There is no standard way to acquire data.
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Current methods range from keyboard to natural
language processing.
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Some health care professionals even use
intermediaries like nurses or secretaries.
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The end goal is to capture patient data without
disrupting the workflow.
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Requirements: Patient Data Validation
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Tons of coding systems exist for the validation of
patient data.
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Sadly none of the existing coding systems capture the
subtle differences and the high details of the patient’s
health care.
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A clinical decision support system should be able to
work with both detailed and general patient data.
 And the system’s performance should not be
affected by the type of data.
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Requirements: Medical Knowledge Modeling
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Knowledge modeling is necessary for the
identification of relationships and concepts.
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Modeling is also used to decide what patient data is
pertinent and what strategies to use.
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These tasks require a large amount of modeling.
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Luckily several methods exist that do a pretty good job
regarding medical knowledge modeling.
 Common KADS [De Hoog et al., 1994]
 CASNET [Weiss et al.]
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Requirements: Medical Knowledge Elicitation
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Current clinical decision support systems obtain
knowledge and then work directly with the clinician.
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But a clinical decision support system should be able
to evoke useful knowledge seamlessly.
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But this implies methods that facilitate the use of
knowledge-bases.
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Requirements: Medical Knowledge Representation
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The interpretation of trends is intuitive for clinicians.
 For example, trends of sickness, trends of the
results of medical treatments.
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Clinical decision support systems must be able to
represent the knowledge like trends.
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But to achieve this, the clinical decision support
system must emulate the clinicians intuition.
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Requirements: Medical Knowledge Reasoning
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Computer systems have the capability of storing large
amounts of factual knowledge.
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Clinical decision support systems should be able to
 Discern which knowledge is useful for the task at
hand.
 Know how to apply the knowledge in order to
obtain worthy results.
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The solution for this requirement is in the realm of
artificial intelligence.
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Requirements: System Performance
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Clinical decision support systems should be able to
use ALL the pertinent data and knowledge available.
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At the same time, the systems should be able to use
the most updated data and knowledge.
 This implies a lot when we talk about the use of
knowledge-bases.
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On top of it all, decision support should appear in an
instant manner while maintaining high accuracy.
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Requirements: Integration to the Workflow
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The most difficult of the requirements to fulfill.
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Integration to the workflow requires fulfilling a couple
of previous requirements:
 Patient Data Acquisition
 Knowledge Representation
 System Performance
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If a clinical decision support system is able to fulfill
these previous three requirements, integration is given.
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Existing Systems
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There has been a surge of clinical decision support
systems from the 1980’s to the present day.
Their applications range from infectious disease
diagnosis to cardiovascular treatment predictions.
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Pathfinder (1992)
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Explains, acquires, represents and manipulates
uncertain medical knowledge.
 Uses probability and decision theory as strategies
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Deductive reasoning is used to provide diagnosis
 But the system is designed so that no
recommendations are done
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The user interface is menu based and mouse driven
 Feature category, observed features and differential
diagnosis are the windows in the initial screen.
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Pathfinder’s Deductive Reasoning Model
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Iliad (1988)
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Uses Boolean and Bayesian frames to represent
knowledge.
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The system has four basic components:
 Inference engine
 User interface
 Data driver
 Best information algorithm
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Currently used as a teaching tool for medical students.
 Particular cases are simulated so that students learn
how to diagnose.
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DiagnosisPro (1993)
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Uses differential diagnosis to remind the user of
possible diagnoses in an effort to reduce medical
errors.
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The knowledge-base is huge:
 11,000 diseases
 30,000 findings
 300,000 relationships
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Information for the knowledge-base is taken from
medical sources such as JAMA, Oxford Textbook of
Medicine and others.
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DiagnosisPro’s User Interface
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Heart Disease Program (HDP) (1980’s – 90’s)
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Assists the clinician in anticipating the effects of
therapy in cardiovascular disorders.
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Uses strategies as:
 Knowledge-base and physiologic model
 Probabilities
 Constraints
 Differential Diagnosis
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The user interface is menu driven
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Heart Disease Program’s Differential Summary
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Clinical Knowledge Summaries (CKS) (2007)
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Helps clinicians make decisions about a patient’s
health and provides strategies on how to use those
decisions.
 Provides knowledge on topics about common acute
and chronic diseases and their prevention
 Offers quick answers on how to manage common
clinical scenarios
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Built on the existing PRODIGY knowledge-base.
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It is a web-based clinical decision support system,
accessible from around the world.
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Clinical Knowledge Summaries’ User Interface
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Dxplain (1987)
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Combines characteristics of an electronic medical
textbook with characteristics of a medical reference
system.
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Provides information on different diseases
 Emphasizes in signs and symptoms
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The knowledge-base includes:
 2,400+ diseases
 5,000+ symptoms, signs, lab data and clinical
findings
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VisualDx (2006)
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Java-based and image driven
 Designed for point-of-care reference
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One of the main functions is the facilitation of image
matching for the end user, achieved with:
 Graphical search tools
 Knowledge-base of relationships
 Thousands of digital images
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Used to develop differential diagnoses based on
morphologic and patient driven search.
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Its focus is on infectious diseases.
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VisualDx’s User Interface
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INTERNIST-1 / QMR Project (1974 - 80’s)
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Designed to provide assistance in general internal
medicine
 Both INTERNIST-1 and QMR rely on the
INTERNIST-1 knowledge-base
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INTERNIST-1 works as a high-powered diagnostic
consultant tool.
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QMR acts as an information tool
 Provides ways to manipulate and review diagnostic
information for the knowledge-base
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EON System (1996)
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Consists of four general purpose components:
 Constructs patient-specific treatment plans
 Infers high level abstract components
 Performs time-oriented queries in time-oriented
patient database
 Allows the acquisition of protocol knowledge
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The design principles that create a base for the EON
system are problem-solving methods and domain
ontologies.
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Because of the difficulties of long-term maintenance
of knowledge-bases, PROTÉGÉ-II is used.
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EON System Architecture
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Snapshot of our clinical decision support systems
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Limitations
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Existing clinical decision support systems suffer from
limitations difficult to overcome.
 Patient’s Role
 Usability
 System Performance
 Knowledge Sharing and Maintenance
 Security
Such limitations slow the adoption rate of clinical
decision support systems.
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Limitations: Patient’s Role
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The patient’s role is not defined in clinical decision
support systems.
Patients are just the source of data for the clinical
decision support system to work on.
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Limitations: Patient’s Role
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The answers to those questions do not only have
implications in a moral or ethical sense, but can also
provide the patient evidence for legal matters.
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The patient will want to know every detail regarding
his health.
 After all, patients provide every bit of their
personal information in order to get the best care.
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Clinicians would like to withhold information for
different matters.
 For example, the clinician would like to be the one
to break the news in case of a serious disease.
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Limitations: Usability
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Biggest hurdle current clinical decision support
systems have to overcome.
 Health care professionals don’t like change.
No current system integrates in the workflow
seamlessly.
 This is the result of shortcomings in system
performance and human-computer interaction.
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Limitations: Usability
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A busy clinician would only want pertinent
information.
A less busy clinician, or one who needs every detail to
reach a diagnosis, would appreciate a high level of
detail.
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Clinicians do not like to modify the usual workflow to
input data.
New methods aim to bridge the gap between nondigital and digital data acquisition.
 For example: TIMOS LINK
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Preference on data input changes by person.
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Limitations: System Performance
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Limitations: System Performance
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Accurate support is the purpose of clinical decision
support systems.
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Current methods are not accurate enough to be widely
used.
 QMR’s accuracy being % in ED scenarios.
 Iliad’s accuracy being % in ED scenarios.
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At the same time, no matter how accurate, if a
decision support takes to long to appear, it is useless.
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Limitations: Knowledge Sharing
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Knowledge-bases are specific to each clinical decision
support system.
Its actually one of the “selling points” of current
solutions.
 Used to differentiate existing systems from others
in an effort to stand above.
The bigger the knowledge-base, the more decision
support (and more accurate) the system is able to
offer.
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Limitations: Knowledge Sharing
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Having a centralized knowledge-base, or at least a
framework that allows for current knowledge-bases to
be shared, would improve reliability and accuracy
across different clinical decision support systems.
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Standards exist in an attempt to consolidate.
 The problem is that there are so many standards,
everyone uses a different one.
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We need a standard of standards.
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Limitations: Knowledge Maintenance
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Maintaining knowledge and managing pieces of the
clinical decision support systems are critical for
successful delivery of decision support.
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Knowledge-base maintenance requires a lot of work.
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Current methods rely on periodical update by humans.
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Limitations: Knowledge Maintenance
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Periodical updates by human intervention is a
primitive approach to knowledge maintenance.
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The latest knowledge and information could be put on
hold for months until the knowledge-base’s update is
due.
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This goes against one of the original requirements:
 Clinical decision support systems should utilize the
latest knowledge available.
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Limitations: Security
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Clinical decision support systems provide an equal
level of recommendations to whoever has access to the
system.
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Clinical decision support systems that exist as part of
an EMR have some level of security.
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Systems that exist as stand alone solutions do not.
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Limitations: Security
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We have to remember that other professionals (such as
nurses, pharmacists, etc.) are an equal part of the
patient’s well-being.
It is natural to think that clinical decision support
systems should have some level of role-based access
control.
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Concluding Remarks
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A long road lies ahead of CDSS.
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Improvements must be made in order to increase the
adoption of clinical decision support systems.
 Usability
 System Performance
 Knowledge Handling
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Existing technologies and ideas offer possibilities to
resolve several of the limitations.
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Other limitations require a compromise in order to be
solved.
CDSS-49