Pismo uredniku
https://doi.org/10.22514/SV132.112017.21
Ed overcrowding – matematic models for integrated solutions and decisions
LUCIANA TEODORA ROTARU
orcid.org/0000-0003-3135-5456
; Emergency Department and First Aid,University County Hospital Craiova, Dolj County
MIHAI BĂNICIOIU - COVEI
Sažetak
Dear Editor In Chief,
We are writing to You in line with an very
interesting point of view regarding the
Emergency Department (ED) development.
The paper titled Improving Emergency
Department Capacity Efficiency,
published in your Journal 2016; 12(1): 52-
57, as an original articles, spotlight solution
for ED crowding.
So we are proposing a mathematics models
for reciprocal accommodation of patients
flows to the response capacity of the ED.
ED overcrowding is not just a reality but a
huge problem, not only on satisfaction of
staff and patients, but also in terms of ED
performance. It is already known that, prolonged
stay in ED is associated with lower
compliance of ACC rules for care of ACS/
NSTEMI (1) and increased mortality for
hospitalized patients.(2,3)
Theoretically, there are two possible approaches:
modulating demand (categorization
and stratification of entries, triage,
types and volume of auxiliary resources
patients, use bifocal FastTrack for reducing
time of wait) or enhancing capacity.
Managing resources to meet demand.
Limiting resources, constraint, (4) implies
a capacity below the request, that must
satisfy (available imagistic investigations,
surgery room, ICU (intensive care unit)
ventilation capacity) (5) and only change
of limiting resources will improve the flow.
The mathematical study of waiting lines
was our model for predicting how systems
serving random arrivals behave.
The flow of patients in the ED can be compared
as an ordinary elementary stream
flow, stationary and independent, called
„Poisson type flow” (the occcured flow can
be calculated by Poisson distribution law).
To an elementary strem flow we can apply
Pearson’s test of validation of probabilities
for arrival of patients flow and time until
patients are admitted.
Applying simulation of this type for such
a process is recommended by the fact that
ED are systems with a large number of
workstations with complex topology, the
time of patients arrival is complicated and
with mixtures of distributions, there is prioritization
and pursuing efficiency targets.
The system of patients admitting can be recalibrated
if some data are known: arivals
distribution and duration of work per patient,
as random or deterministic variables,
number of workstations, approach algorithme,
system capacity.
It is important from the beginning if the ED
is considered as an closed system, an open
system with infinite source of workstations
with refusal, (for improvement, number of
workstations should be increased), open
systems (a number of patients waiting). or
open system with limited number of stations
(no refusal).
High rates of use in systems with many variations
generates very long periods of waiting.
In high level of usage, small changes
can dramatically affect user waiting time,
both in good or bad way. A small change
could be represented by the increase of
minimum workstations, but mathematically
if only number of service providers
increases, also waiting time will increase
exponentially.
Conclusion is that modeling results depend
on how emergency system is interpreted
and placed in the typology of queuing systems,
then to realize analytical study for
distribution of time between presentations
and admitting time, patient approach policies,
and than can be deduced mathematical
formulas of efficiency factors of the
system.
Ključne riječi
Emergency Department; overcrowdind; Poisson flow; Pearson’s test; constraint; ED capacity
Hrčak ID:
190634
URI
Datum izdavanja:
12.12.2017.
Posjeta: 1.033 *