Presented by Bryan Houliston Auckland University of Technology

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Aura Laboratory

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My road to Health Informatics1
Anaesthetic activity 2
Outline
Research methodology3
Design and development 4
Results and Conclusion5

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My road to Health Informatics
• 1991 Graduated B.Comm
• 91 - 02 Worked in software development
• 03 – 04 M.InfoTech at AUT

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Anaesthesia
• “Extreme approximation of death” (Euliano, 2004)
• “…that even today we understand but partly”
(Eger, 2006)
• “Every complication has the potential to
cause lasting harm to the patient…
deviations from the norm must be recognised
promptly and managed appropriately”
(Aitkenhead, 2007)

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Complications
• 49% of preventable adverse events due to
„system factors‟
• Poor record keeping
• Lack of information
• Few standard procedures
• Failure to adhere to standards
• Poor communication
• Organisational culture (Davis, 2003)

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Solutions
• Standard procedures
• WHO Safer Surgery Checklist
• Recording, Adherence to procedures

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Task analysis
• “A scientific description of the
anaesthetist’s task patterns and workload
would aid in our understanding of the
nature of anaesthetist’s job…and provide
a rational basis for making improvements”
(Weinger, 1994)
• “A scientific description of the
anaesthetist’s task patterns and workload
would aid in our understanding of the
nature of anaesthetist’s job…and provide
a rational basis for making improvements”
(Weinger, 1994)
• Evidence-based medicine requires
scientific data to justify improvements

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Gold standard for data collection

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‘Scientific description’ ?
Observation
Detailed ? No
Objective ? No
Consistent ? Unlikely
(Slagle, 2002)

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Can we build a system able
to capture more scientific
data, with less risk of
distraction, and lower
ongoing cost?
Scientific
value ?
Potential
distraction
Expensive
Automated Observation ?

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Design Science methodology
(Offermann, 2009)
Humans are not ideal
instrument for capture
of scientific data
Anaesthetic record
Drug Prep
Location + orientation
AURA Lab
ACSC field test
Simulated procedures

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Hidden Markov
Model
Bayesian
network
A priori rules
Body movement
Location
Object use
Voice / sound
Video
Accelerometer
RFID
Audio
Motion detectors
Contact switches
Flow meters
Sensors Measure Inference
Activity detection systems

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Rules
HMMs
(Hidden Markov
Models)
Proximity
LOS
(Location +
Orientation +
Stance)
RFID
(Radio
Frequency
Identification)
Sensors Measure Inference
TADAA

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Anaesthetic Record Action Zone
Rule: If reader detects any wristband tag then
Recording is happening

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ARAZ results
Lab Field tests Simulations
98 81
100
77 66
96 47
100
0 0
Specificity
97%
Sensitivity
69%

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Drug Trolley Action Zone
• Rule: If reader detects any wristband tag
then Drug Prep is happening

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DTAZ results
Field tests Simulations
Specificity
73%
Sensitivity
56%
0
100 100
10
64 10099

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Activity Fingerprinting
• Signal strength „fingerprint‟ built up from
multiple tags and readers

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Activity Fingerprinting 2
• Fingerprints associated with a location +
orientation through SOM clustering

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Activity Fingerprinting 3
= Drug Admin IV
• Location + orientation sequences associated
with activity through HMM analysis
1 second at drug trolley
then 2 seconds at machine
then 3 seconds at patient

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Activity Fingerprinting 4

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AF results
Lab Field tests Simulations
SOM
accuracy
99%
HMM
accuracy
97%
SOM
accuracy
88%
HMM
accuracy
10%
SOM
accuracy
97%
On new data
66%

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Distraction
• Rated on VAS, converted to 0-100
0
10
20
30
40
50
60
70
80
Tags Readers Observer
Distraction - Tags & Readers vs Observer (n=20)

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TADAA Observer
Hardware
Readers x3
Tags x16
Cabling
Laptop
$450
$950
$200
$600
Tablet PC $1000
OTS
Software
COM monitor $50
Labour Install (4 hours) $100
Ongoing
(annual)
Replace tags $190 Wage $40000 ?
Cost

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Conclusion
• ARAZ very good at sensing Recording activity
• DTAZ good at sensing Drug Prep
– But needs more rules to distinguish other
activity at drug trolley
• AF very good at sensing anaesthetist location +
orientation
– But requires better activity inference
mechanism
• RFID sensors less distracting than observers
• Higher upfront cost, but lower ongoing cost

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Future development
• Refine rules
– Switching semi-HMM? (Duong, 2005)
• Identify lower level activities
• Additional sensors
– Tag objects - syringes, intubation equipment
– Voice detection for „conversing‟ activities
– Gaze detection for „observing‟ activities

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Future development
• Real-time viewer
– Communication to staff outside theatre
• Repository of activity records
– Research unfamiliar procedures
– Mine by anaesthetist
– Mine by procedure type, patient condition, etc
• Formulate „best practice‟ for procedure
– Recognise deviations in real-time, raise alarm

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Aura Laboratory

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References
Aitkenhead, A. R., Smith, G., & Rowbotham, D. J. (Eds.). (2007). Textbook of Anaesthesia
(Fifth ed.): Elsevier Limited.
Davis, P., Lay-Yee, R., Briant, R., Ali, W., Scott, A., & Schug, S. (2003). Adverse events in New
Zealand public hospitals II: preventability and clinical context. New Zealand Medical Journal,
116(1183).
Duong, T. V., Bui, H. H., Phung, D. Q., & Venkatesh, S. (2005). Activity Detection and
Abnormality Detection with the Switching Hidden Semi-Markov Model. Paper presented at
the IEEE Conference on Computer Vision and Pattern Recognition.
Euliano, T. Y., & Gravenstein, J. S. (2004). Essential Anaesthesia From Science to Practice.
Cambridge, UK: Cambridge University Press.
Kohonen, T. (2008). Data Management by Self-Organising Maps. Paper presented at the IEEE
World Conference on Computational Intelligence, Hong Kong, June 1-6.
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Anaesthesia > Task Analysis > TADAA > Evaluation > Conclusion

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References
Peffers, K., Tuunanen, T., Rothenberger, M. A., & Chatterjee, S. (2008). A Design Science
Reseach Methdology for Information Systems Research. Journal of Management
Information Systems, 24(3), 45-77.
Slagle, J., Weinger, M. B., Dinh, M. T. T., Brumer, V. V., & Williams, K. (2002). Assessment of
the Intrarater and Interrater Reliability of an Established Clinical Task Analysis Methodology.
Anesthesiology, 96(5), 1129-1139.
Smith, A. F. (2009). In Search of Excellence in Anesthesiology. Anesthesiology, 110(1), 4-5.
Weinger, M. B., Herndon, O. W., Zornow, M. H., Paulus, M. P., Gaba, D. M., & Dallen, L. T.
(1994). An Objective Methodology for Task Analysis and Workload Assessment in
Anaesthesia Providers. Anesthesiology, 80(1), 77-92.
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Anaesthesia > Task Analysis > TADAA > Evaluation > Conclusion