Clinical Care Algorithms:
The Good, The Bad,
and The Ugly
R. Matthew Sailors, PhD
UTH Medical School
Department of Surgery
Overview
• Modern World / Why Use Algorithms
• Types of / Uses for Algorithms
• Clinical Care Algorithms
– Types, Use, Automation
•
•
•
•
Good, Bad, and Ugly Algorithms
Algorithm Classification & Examples
Evaluating Algorithms
Writing Good Algorithms
Modern World
• Society is making ever greater demands on our
healthcare delivery system and, in turn, on the
healthcare providers.
• It is imperative that the workflow of healthcare
delivery be altered if quality of care and access
to healthcare are to be maintained or improved.
• One of the many ways of accomplishing this
alteration is the automation of clinical
algorithms
Why Do We Use Algorithms?
• Share or extend expertise
– Training
– Disseminate processes / procedures
• Reduce variability
• Standardize care
– Improve overall quality of service
– Serve as baseline for new strategies
• Medico-Legal reasons
Types of Algorithms
• Clinical
• Administrative
• Financial
• Time-based
• Data-based
• State-based
•
•
•
•
Evidence-based
Heuristics
Model-based
WAG
Clinical Care Algorithm
• Specifically clinical (patient care)
• NOT
– Financial
– Administrative
– Resource allocation
• Neutral, high-level term
– No biases or preconceptions
Clinical Care Algorithm
• Description of a process intended to guide
sequential clinical (therapeutic or
palliative) interventions.
• Usually single patient-centric
• Time or data-driven
• Evidence-based, models, heuristic, WAG
Clinical Care Algorithm
Protocol (I)
Protocol (II)
Care Path(way)
Knowledge Base
Practice
Guideline
Care Plan
Procedure
This is not a hierarchy diagram, just a terminology
Use of Clinical Algorithms
• Serve only as guides
• Only good inside the design envelope
• Professional clinical judgment override
• Handle “routine” situations
• Allows experts to concentrate on difficult
cases
Automation of Clinical Algorithms
• guide (but not directly provide) therapies
• manage information flow
• assist in diagnosis and treatment
planning
• provide a safety net for the patient for the
times when the inevitable human /
technical / system errors occur.
Automation of Clinical Algorithms
• Computers have no native intelligence
• Algorithms must be as detailed as
possible
– streamline the implementation process
– computerized algorithm must represent
• what we want to do
• not just want we told the computer to do.
Good Algorithms -- Required
1. Concise description
•
•
Content and intent of the algorithm
Patient groups to which it can and cannot
be safely applied
2. Structured, repeatable algorithm
•
textual or graphical form
3. Fully specified concepts
•
(e.g., “high nasogastric tube output is defined
as nasogastric tube output > 1200 cc/12 hr”)
Good Algorithms -- Required
4. Fully specified decision points
•
E.g., PaO2 >= 60 and PaO2 <= 80
5. Fully specified action steps,
•
•
•
Therapeutic interventions suggested by the
algorithm
Calculations to be performed
Patient-specific recommendations
Good Algorithms -- Desired
1. Formal expression language
•
•
•
Describe the decision and action steps
Delineated scope and purpose
Define entry and exclusion criteria
2. Formalism to describe the flow of the
algorithm from one state to the next
3. Encoded links
•
•
•
Didactics
Reference materials
On-line resources
Bad Algorithms
• Full of vagaries (“weasel words”)
– “optimize patient’s respiratory status”
• Fail to adequately describe the decisions
and actions that are required to care for
the patient
• Important entry or exclusion criteria and
conditional values missing
• Concepts poorly defined
– “high NG output”
Ugly Algorithms
• Unstructured / poorly structured algorithm
• Algorithm follows no sequential order
• Important entry or exclusion criteria appear
at the end of the algorithm or in footnotes
• No standard formalism used to describe
algorithm
Algorithm Classifications
• Proposal to HL7 Clinical Decision
Support Technical Committee
• 5 levels
–0–4
– Increasing detail with higher classification #
Class 0
• Often encoded only in textual form.
• Full of vagaries
• Fail to adequately describe the decisions and
actions that are required to care for the patient
• Actual algorithm
– often unstructured or poorly structured
– may follow no sequential order
• Important entry or exclusion criteria and
conditional values often appear at the end of
the algorithm or in footnotes, if at all.
Class 1
• Improve upon Class 0 algorithms
• All of the entry and exclusion criteria specified
at the beginning of the description.
• Algorithms steps are coarsely structured and
are arranged in a temporal or logical
progression.
• Algorithms are usually still represented in
textual form, but may also be represented in
other forms.
Class 2
• Improve upon Class 1 algorithms
• Explicitly defining all thresholds and
decisions within the algorithms.
• Some action steps are also defined.
Class 3
• Distinguished from Class 2 algorithms by
– Representation format
– Presence of definitions for all steps
• Represented using structured formalism
– flow diagrams
– formal, structured text (pseudo-code)
Class 4
• Include all of the details necessary for a nonexpert or computer to negotiate the algorithm
in a reliable and repeatable manner.
• All logical and clinical concepts are explicitly
spelled out and are described in terms of
patient-specific values.
• Most often disseminated as either flow
diagrams or encoded using a knowledge base
formalism.
Intermediate Classifications
• A given clinical algorithm may fulfill all of the
requirements for a given classification and part
of the requirements for a higher classification
• May be necessary to classify the algorithm as a
intermediate value.
• Separate the two levels with a forward slash (/),
such as, “Class 3 / 4”.
• This notation, while less precise than a decimal
or true fractional notation, has the advantage
of being simple and efficient.
Classification Overview
Algorithm Class
0 1 2 3 4
concise description of content and intent of algorithm
+/- + + + +
description of inclusion and exclusion patient groups
+/- + + + +
structured repeatable algorithm
+/- +/- + + +
fully specified concepts
- +/- + + +
fully specified decision points
- - + + +
fully specified action steps
- - +/- + +
formal expression language
- - - +/- +
formalism to describe the flow of the algorithm
- - - - +
encoded links to didactics, references, on-line resources - - - - +/Elements of a “Good” Algorithm
+ := always present
- := always absent
+/- := may be present
Class 0 AED Algorithm
1.
2.
3.
4.
5.
6.
7.
8.
9.
ABC’s, start CPR, apply AED
Push “analyze”, if indicated defibrillate at 200 J
If no conversion, defibrillate at 300 J
If no conversion, defibrillate at 360 J
Check pulse, if present, support airway
If no pulse, CPR for one minute
Check pulse, if absent press “analyze”
If advised, defibrillate up to three times at 360 J
Repeat steps 2 thru 8 until arrival at medical facility
Class 0 AED Algorithm (cont.)
Notes:
A. Single rescuer with AED should verify
unresponsiveness, open airway give two breaths, and
check pulse. If full arrest, AED should be attached
and proceed with algorithm.
B. Pulse checks are not required after shocks 1, 2, 4, and
5 unless “no shock indicated” is displayed
C. Only to be used on pulse-less, non-pediatric patients
D. If advanced personnel are present, they can use the
manual mode
E. Advanced personnel can enter the above algorithm at
any point and continue with appropriate advanced
protocol
Class 1 AED Algorithm
Notes:
A. If advanced personnel can use the
manual mode
B. Advanced personnel can enter the
algorithm at any point and continue
with appropriate advanced protocol
Class 1 AED Algorithm (cont.)
1.
If patient has pulse or is a pediatric patient then do not continue
with algorithm. Instead use alternate algorithms for VF
2. Single rescuer with AED should verify unresponsiveness, open
airway give two breaths, and check pulse. If full arrest, AED
should be attached and proceed with algorithm. If multiple
rescuers then ABC’s, start CPR, apply AED
3. Push “analyze”, if indicated defibrillate at 200 J
4. If “no shock indicated” then check pulse
5. If no conversion, defibrillate at 300 J
6. If “no shock indicated” then check pulse
7. If no conversion, defibrillate at 360 J
8. Check pulse, if present, support airway
9. If no pulse, CPR for one minute
10. Check pulse, if absent press analyze
11. If advised, defibrillate up to three times at 360 J
12. Repeat steps 3 thru 11 until arrival at medical facility
Class 2 AED Algorithm
Notes:
A. If advanced personnel can use the
manual mode
B. Advanced personnel can enter the
algorithm at any point and continue
with appropriate advanced protocol
Class 2 AED Algorithm (cont.)
1.
If patient has pulse or patient age <= 8 years then do not continue with
algorithm. Instead use alternate algorithms for VF
2. Single rescuer with AED should verify unresponsiveness, open airway give
two breaths, and check pulse. If full arrest, AED should be attached and
proceed with algorithm. If multiple rescuers then ABC’s, start CPR,
apply AED
3. Push “analyze”, if AED displays “shock indicated”, defibrillate at 200 J
4. If “no shock indicated” then check pulse
5. If AED displays “shock indicated” (no conversion), defibrillate at 300 J
6. If “no shock indicated” then check pulse
7. If AED displays “shock indicated” (no conversion), defibrillate at 360 J
8. Check pulse, if present, support airway
9. If no pulse, CPR for one minute
10. Check pulse, if absent press analyze
11. If AED displays “shock indicated”, defibrillate up to three times at 360 J
12. Repeat steps 3 thru 11 until arrival at medical facility
Class 3 AED Algorithm
start
yes
no
yes
pt. age > 8 yrs
pulse present?
yes
responsive
no
no
performs ABCs
open airway
no
wait 1-3 minutes
no
yes
# rescuers = 1
yes
initiate CPR
"shock advised" ?
breathing
apply AED and
turn unit on
press "analyze"
no
give 2 breaths
yes
perform CPR for 1 min.
defib. at 200 J
no
pulse ?
check pulse
yes
yes
conversion ?
no
pulse ?
defib. at 300 J
yes
no
defib. at 360 J
yes
conversion ?
no
yes
conversion ?
defib. at 360 J
no
defib. at 360 J
support airway
yes
pulse ?
conversion ?
no
no
yes
no
defib. at 360 J
at hospital?
yes
use alternate
algorithm
end
check pulse
Class 4 AED Algorithm (Part 1)
start
yes
yes
pt. age > 8 yrs
check pulse
yes
pulse present?
yes
# rescuers = 1
responsive
no
no
performs ABCs
open airway
initiate CPR
breathing
no
no
wait 1-3 minutes
no
yes
"shock advised" ?
press "analyze"
apply AED and
turn unit on
yes
conversion ?
no
pulse ?
defib. at 300 J
yes
no
defib. at 360 J
yes
conversion ?
no
yes
conversion ?
defib. at 360 J
no
defib. at 360 J
support airway
yes
pulse ?
conversion ?
no
no
yes
no
defib. at 360 J
at hospital?
yes
use alternate
algorithm
give 2 breaths
check pulse
check pulse
yes
pulse ?
yes
perform CPR for 1 min.
defib. at 200 J
no
no
end
Class 4 AED Algorithm (Part 2)
remove patient clothing
that may interfere with
AED use
AED brand = X ?
turn AED on by lifting monitor
screen to "up" postition
turn AED on by pressing
power switch
clear area for AED and
rescurer on patient's left side?
open first defibrillator pad
place AED close to supine
patient's left ear
place AED close to supine
patient's right ear
rescuer position on patient's
left side
rescuer position on patient's
right side
attach first pad in the anterior position -right (patient's right) of the upper sternum (breast
bone) and below the clavicle (collar bone)
open second defibrillator pad
attach second pad in the apex position -left (patient's left) of the nipple with the
center of the electrode in the midaxillary line
(where the chest and armpit meet)
Critically Evaluating Algorithms
• Identify target audience
– Experts
– Novices
– Related fields
• Identify intended use
– Author’s
– Yours
• Look for well-defined decision and action
targets (no “weasel words”)
• Look for individual-based outputs
Critically Evaluating Algorithms
• Look for well-defined decision and action
targets (no “weasel words”)
• Look for individual-based outputs
• Use the table to help classify algorithms
Algorithm Class
0 1 2 3 4
concise description of content and intent of algorithm
+/- + + + +
description of inclusion and exclusion patient groups
+/- + + + +
structured repeatable algorithm
+/- +/- + + +
fully specified concepts
- +/- + + +
fully specified decision points
- - + + +
fully specified action steps
- - +/- + +
formal expression language
- - - +/- +
formalism to describe the flow of the algorithm
- - - - +
encoded links to didactics, references, on-line resources - - - - +/Elements of a “Good” Algorithm
+ := always present
- := always absent
+/- := may be present
Writing Good Algorithms
• Start with general and work to specific
– Iterative process
• Avoid Gotchas -- later slide
• Think like a child (or engineer)
– Simple, discrete, decisions
• Keep it simple at first
• Add complexity as needed
Tips
• Simple binary (yes / no) decisions
involving 1 or 2 data points
– X < 25
– X > 36 or Y <= 18
• String together lots of small steps rather
than having one or two big ones
• Nest complexities away
Gotchas
•
•
•
•
•
•
Over generalizations
“Weasel Words”
Being Too Ambitious
Not Understanding Problem Domain
Trying to Solve Wrong Problem
Trying to Use Wrong Techniques
Summary
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•
•
•
•
•
Algorithms – many uses: for good, for bad
Good, bad, and ugly algorithms
Good algorithms share expertise
Algorithm classifications: 0 (low) – 4 (high)
Critically evaluate algorithms
Writing good algorithms is about attention
to details