alerting. The purpose of our paper is to illustrate the
software-side of the proposed cyber-physical system
using a motivating example based on one of the most
relevant, and often occurring clinical workflows.
On the software side, the system will model and
encode clinical workflows using the Business Process
Modelling and Notation (BPMN) (Object Manage-
ment Group, 2015) standard and it will be compati-
ble with leading medical informatics standards such
as HL7 V3 (Health Level Seven International, 2016),
thus allowing seamless interconnection to hospital in-
frastructure via HL7-compliant Hospital Information
Systems (HIS). In addition, it will integrate a network
of hardware sensors, able to identify ongoing clini-
cal processes, provide location information and track
the use of hospital equipment and materials. Health-
care workers will use wearable devices that continu-
ously monitor their location and activity. The central
hub of the system will be a server side engine able to
load and execute BPMN-based workflows. Integra-
tion with the HIS enables the retrieval of key informa-
tion regarding patients, such as admissions, transfers
and discharges as well as records of past of planned
invasive interventions, which can be used to deter-
mine the level of risk. Hence, infections and outbreak
management could be improved so that in case of sus-
picion, the locations of previous admissions, as well
patients of members of staff considered at risk can be
contacted.
The modelled clinical workflows will be executed
using a BPMN engine. When the workflow leads to
a state that is a risk of HAI, the engine will gener-
ate alerts that are received directly by the involved
healthcare workers. In this paper we illustrate the in-
terplay between the hardware and software compo-
nents of the proposed system using a motivating ex-
ample based on hand hygiene, which remains one of
the most common pathways of HAI transmission. We
must note that the provided example is only used to
portray the workflow-based system, and that the final
implementation will allow the creation and monitor-
ing of a variety of clinical workflows, that will be ex-
ecuted by the BPMN engine whenever necessary.
We illustrate our motivating example using a typ-
ical scenario: a healthcare worker enters a room with
two beds, and interacts with both inpatients before ex-
iting. Both common as well as highly relevant to hand
hygiene, our example is illustrated in Figure 2, using
simplified BPMN-like notation to reduce the number
of decision points and emphasize readability.
According to established hand hygiene guidelines
(World Health Organization, 2016), upon entering a
patient room, workers must perform hand disinfec-
tion. If this procedure is skipped or performed in-
adequately (e.g. without disinfectant, shorter wash-
ing time than recommended), the system will gener-
ate an alert to warn the clinician about the detected
non-compliance. After each patient contact, and be-
fore leaving the room, hand disinfection should again
be correctly performed. All these events and alert re-
ports will be persisted to enable later analyses, such as
identification of an outbreak’s patient zero and route
of transmission.
Figure 1, which was adapted from (Shhedi et al.,
2015) illustrates a typical patient room, with two
beds, a sink and a bathroom. As soon as the healthcare
worker enters it, the Radio-Frequency Identification
(RFID) tag and motion sensor combination detect this
and identify them. The system records and interprets
the data received from the sensors and the BPMN en-
gine starts a new instance of the relevant workflows,
including the one for hand-hygiene. According to the
hand hygiene workflow, the clinician should perform
the hand disinfection procedure before going near a
patient and before leaving their surrounding. In our
example, this is achieved using the sink or the bath-
room sink and the disinfectant dispenser. All of them
have inexpensive sensors together with RFID tags and
Bluetooth Low Energy transceivers; their role is to
provide input to the workflow engine. The workflow
engine records received data into the persistent repos-
itory. Furthermore, by running the workflow, the soft-
ware engine ascertains that hand hygiene guidelines
were observed. In our example, the healthcare worker
performs hand disinfection before contact with the
first patient, which is recorded by the sensors inte-
grated with the sink and the disinfectant dispenser.
However, the worker can move to the second patient
directly, as shown in Figure 2. In this case, the system
records their proximity to the second bed via RFID;
if a disinfection event that is compliant with guide-
lines was not recorded before the contact, the system
interprets this as non-compliance, and emits an alert
that is recorded and received by the healthcare worker
through their wearable device. Once they become
compliant by undergoing hand disinfection, they can
resume contact with the patient. Information that is
persisted is planned to be reused at later dates and in
the context of more than one workflow, including at
least all the workflows active during that time. As an
example, the room entry and exit events from Figure
2 can be used for finding the source of an outbreak, or
tracking its propagation. In our example, the current
instance of the hand hygiene workflow ends once the
healthcare worker exists the patient room.
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