The first prehospital stage is the occurrence of
a health-threatening event. As long as no sen-
sors/witnesses detect such occurrence, the timer T0
in Figure 3 increments and the state “Occurrence" re-
mains unchanged. The location of the event (e.g. ur-
ban, desert, or ocean), its sudden occurrence, and the
absence of any instant localization methods, would
make the event undetectable for quite a long time.
Even if the event has been detected (state “Detection"
in Figure 3) and notified (state “Notification" in Fig-
ure 3), and even if a rescue team is dispatched (state
“Dispatch" in Figure 3), the localization of the event
may take long time and may even never been reached
by the dispatched personnel. Therefore, the system
would be stuck at the state “Dispatch" with long du-
ration of the timer T3 (if its limit is not exceeded),
until arrival to the event’s site. An example of such an
event is the Malaysian flight MH370 that went miss-
ing on March 8th 2014, and has neverbeen found after
five years of the incident (as of the time of writing this
article), despite extensive search efforts in the Indian
ocean (Mujeebu, 2016).
Once the occurrence of an event is detected, timer
T0 stops and timer T1 starts and increments until no-
tification of the event is performed. Detection of an
event can be done through sensors, cameras, or wit-
nesses. Event’s notification may promptly happen,
which indicates a short duration of T1, whereas timer
T2 starts and increments up to dispatching appropriate
rescue measures. Communication technologies used
in the notification stage would be based on one of
the wireless standards or cellular networks, or even
through satellites or optical fibers. Once a rescue
team is dispatched with appropriate tools, T2 stops
and timer T3 starts and increments up to the arrival
to the event’s scene. The arrival to the event’s site
marks the end of T3 duration and the beginning of T4
duration. The difficulties encountered on site can be
overwhelming, which leads to a long duration of T4.
The places hit by an earthquake or a tsunami are ex-
amples of overwhelming locations that cause lengthy
duration of T4, before any initial care starts on site.
Sometimes, on-site care can be initiated by un-
trained bystanders before the arrival of health profes-
sionals. Even though such on-site care is highly rec-
ommended in the absence of trained persons, and can
be really critical to save a victim’s life, it is not usu-
ally included in the typical emergency system since it
is not performed by health professionals. However, if
on-site care is established by trained bystanders, arriv-
ing health professionals may temporarily rely on such
care for some victims, in order to treat other victims
at the same time. Therefore, in some circumstances,
the stage of initial care on the event’s site performed
by bystanders would occur before the dispatch of a
rescue team, before the team’s arrival, or after their
arrival. Therefore, the timer T5 in the model of Fig-
ure 3 does not stop until the victim is carried to a ve-
hicle, such an ambulance, that takes its route toward a
nearby hospital.
En route to the hospital, the rescue team in a ve-
hicle or an ambulance would be able to notify the
hospital’s emergency personnel of the patient’s health
status, using wireless communications. In this stage,
the timer T6 in Figure 3 depends on the traffic cir-
cumstances and route difficulties, and it only stops
when the patient actually reaches the hospital. Sub-
sequently, the timer T7 starts and increments until the
emergency personnel start their diagnosis and treat-
ment of the patient.
4 TIMING ANALYSIS OF A
PREHOSPITAL EMERGENCY
SYSTEM
The ASM-based smart emergency system facilitates
timing analysis of the featured stages in order for the
management to evaluate the duration of each prehos-
pital emergency case. Such timing information of
many cases ensures on-going improvementof prehos-
pital emergency systems.
4.1 Single-event Prehospital Emergency
System
The typical prehospital ASM chart presented in Fig-
ure 3 is based on each health-threatening event. When
a single individual person is involved in the event, the
ASM chart identifies the prehospital stages and cal-
culates the overall prehospital emergency duration D,
where D is:
D = T0 + T1 + T2 + T3 + T4 + T5 + T6 + T7.
However, when several casualties resulted from
a single event, the timers T0, T1, and T2 (for
stages “Occurrence," “Detection," and “Notification"
respectively in Figure 3) remain the same as they
are common to the event with multiple casualties,
and the timers T3 and T4 (for stages “Dispatch" and
“Site_Arrival" respectively in Figure 3) are associated
with each team dispatched to the same event loca-
tion, whereas the timers T5, T6, and T7 (for stages
“OnSite_Care," “To_Hospital," and “Hosp_Emerg"
respectively in Figure 3) can be different for each
individual casualty. Therefore, the total emergency
event duration can be formulated as a summation of
three duration periods T
e
, T
d
, and T
i
as follows: