terface design was improved based on usability stud-
ies using a task list and a modified MPUQ. Whereas
the study participants had a diverse range of experi-
ence and demographics that was helpful for interface
design improvement, we could not test the effect of
language or cultural barriers, as all subjects were En-
glish speaking and living in Canada. We are currently
conducting the same usability studies in Africa with
a wide range of potential end users (e.g. anesthesia
technician). The high acceptance rate obtained from
our Canadian study and the intentional minimal use of
English words in the Home and Settings screen sug-
gests that adoption could be universal.
The Phone Oximeter application prototype con-
sists of our developed software and interface, an iPod
Touch and a Nonin Xpod pulse oximeter. The iPod
Touch was able to provide power for the pulse oxime-
ter sensor for five hours, which included continuous
recording and display of data without dimming the
screen. Most phones have a substantially larger bat-
tery and will, therefore, be able to operate the applica-
tion for a longer period of time. This will be sufficient
for most operating scenarios conducted in the devel-
oping world. If required, additional autonomy could
be provided by an additional battery pack to power
the pulse oximeter sensor independently.
The current prototype is based on a wired connec-
tion between sensor and phone. This is an advantage
for power consumption and designing the commu-
nication protocol, since less complex layers are re-
quired. However, our current implementation does
not provide the required electrical isolation between
the iPod Touch and oximeter device. This will be
solved in upcoming versions with an improved elec-
tronic isolation circuit or through wireless communi-
cation between sensor and display device. This will,
however, increase power consumption and costs, and
reduce autonomy.
Further work will include the improvement of the
embedded algorithms for the computation of HR, RR
and SQI. We also plan to include a clinical decision
support engine that will have the potential to increase
the reliability of the warning and alarm messages.
We have demonstrated an approach to design a
user interface for visualization of HR, RR, and SpO
2
data for use on a size-restricted mobile phone display
to be used in remote locations by healthcare workers
with little to no prior training. This will offer great
potential in deploying low-cost, life-saving devices in
the ORs of developing countries without significant
investments in training and infrastructure.
ACKNOWLEDGEMENTS
The authors would like to thank all subjects for par-
ticipating in the interface evaluation study. Ali Buttar
and Shona Massey designed the cardboard mockups
for the participatory design process. Dr. Speciosa
Mbula Kimenye and Dr. Jacqueline Hudson assisted
in the usability study.
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