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ISDS 2012 Conference Abstracts

Adaptation of GUARDIAN for Syndromic Surveillance
During the NATO Summit
Julio C. Silva1, Dino P. Rumoro1, Shital C. Shah1, Gillian S. Gibbs*1, Marilyn M. Hallock1,
Michael Waddell2 and Shon Doseck2

1Rush University, Chicago, IL, USA; 2Pangaea Information Technologies, Chicago, IL, USA

Objective
To develop and implement a framework for special event surveil-

lance using GUARDIAN, as well as document lessons learned post-
event regarding design challenges and usability.

Introduction
Special event driven syndromic surveillance is often initiated by

public health departments with limited time for development of an
automated surveillance framework, which can result in heavy reliance
on frontline care providers and potentially miss early signs of emerg-
ing trends. To address timelines and reliability issues, automated sur-
veillance system are required.

Methods
The North Atlantic Treaty Organization (NATO) summit was held

in Chicago, IL, May 19-21, 2012. During the NATO summit, the
Chicago Department of Public Health (CDPH) was charged with col-
lecting and analyzing syndromic surveillance data from emergency
department (ED) visits that may indicate a man-made or naturally oc-
curring infectious disease threat.

Ten days prior to the NATO summit surveillance period, Rush Uni-
versity Medical Center (RUMC) received a guidance document from
CDPH outlining the syndromes for systematic surveillance, specifi-
cally febrile rash illness, localized cutaneous lesion, acute febrile res-
piratory illness, gastrointestinal illness, botulism-like illness,
hemorrhagic illness, along with unexplained deaths or severe illness
potentially due to infectious disease and cases due to toxins or sus-
pected poisoning. RUMC researchers collected relevant ICD-9 codes
for each syndrome category. 

GUARDIAN (1), an automated surveillance system, was pro-
grammed to scan patient charts and match free text using National
Library of Medicine free-text term to unique medical concept, which
were further mapped to relevant ICD-9 codes. The baselines were de-
veloped using ED patient data from 1/1/2010 to 12/31/2011. Statis-
tical references were established for unsmoothed, 24 hour counts
(Baseline = Average; Threshold = +2 standard deviations). 

During the NATO surveillance timeframe (May 13- 26, 2012) au-
tomated results with prior reporting period’s counts, reference statis-
tics, and charts were electronically sent to CDPH. In addition, ED
charge nurses made manual surveillance reports by telephone at least
daily. Open lines of communication were maintained between RUMC
and CDPH during the event to discuss potential positive cases. In ad-
dition, a post-event debriefing was conducted to document lessons
learned.

Results
The automated GUARDIAN surveillance reports not only pro-

vided timely counts of potentially positive cases for each syndrome

but also provided trend analysis with baseline measures. The
GUARDIAN User Interface was used to explain what data points
could trigger positive cases. The Epic system was used to review pa-
tient charts, if further explanation was necessary. The observed counts
never exceeded +2 standard deviations during the NATO surveillance
period for any of the syndromes.

Based on the debriefing meeting between RUMC and CDPH, the
top three achievements and lessons learned were as follows:

1. Quick turnaround time (~ 10 days) from surveillance concept
development to automated implementation using GUARDIAN

2. Surveillance data was timely and reliable
3. Additional statistical information was beneficial to put trends in

context
4. System may be too sensitive resulting in false alarms and addi-

tional investigative burden on public health departments
5. Need for development of user-interfaces with drill down capa-

bilities to patient level data
6. Clinicians don’t necessarily utilize exact terminology used in

ICD-9 codes which could result in undetected cases.

Conclusions
This exercise successfully highlights rapid development and im-

plementation of special event driven automated surveillance as well
as collaborative approach between front-line entities such as emer-
gency departments, surveillance researchers, and the department of
public health. In addition, valuable lessons learned with potential so-
lutions are documented for further refinements of such surveillance
activities.

Keywords
Emergency department; NATO Summit; automated surveillance

Acknowledgments

GUARDIAN is funded by US Department of Defense, Telemedicine and
Advanced Technology Research Center, Award numbers W81XWH-09-
1-0662 and W81XWH-11-1-0711.

References

J. Silva, D. Rumoro, M. Hallock, S. Shah, G. Gibbs, M. Waddell, K.
Thomas, Disease profile development methodology for syndromic
surveillance of biological threat agents, Emerging Health Threats
Journal, 2011, 4:11129.

*Gillian S. Gibbs
E-mail: Gillian_Gibbs@rush.edu

Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org * 5(1):e192, 2013