Analysis of Emergency Medical Response Service in Peshawar through Simulation

EMRS (Emergency Medical Response Service) is the public safety system that is responsible for the initial first aid and transportation of the patient to the hospital. Providing a timely response to any emergency situation is of critical nature and needs to be addressed in the shortest possible time. Decreasing the response to an emergency site and timely pre-hospitalization care location identification and number of emergency response personnel and vehicles are some of the critical elements of EMRS. In this research, a probabilistic model is developed which incorporates the probabilistic response to any emergency situation. The developed model was applied to an actual scenario of the EMRS in the city of Peshawar, Pakistan. The EMRS has 7 locations covering 7 different regions of the city covering more than 1200 square kilometers area. The main purpose of the study is to measure the quality of EMRS on the basis of response time and queue. The study has identified that station 1 and 2 have the highest utilization; 58% each, while station 7 has the lowest utilization at 13.7%. Since the emergency care at the site of incidence is one of the primary responsibilities of the public safety organizations so this study also discusses the average instantaneous utilization of EMRS resources for that region.


INTRODUCTION
T he provision of effective and time dependent emergency and ambulance response service is a problem that is being faced by almost all the major cities around the world. The EMRS technicians are first at the site of incident to provide quick and adequate stabilization to sick and injured patients. The purpose of emergency medical response service is to respond promptly to the emergency calls by providing first aid services and shifting patients, if required, to the emergency care unit of the nearest hospital [1]. Indeed, proper pre-hospital care can reduce casualty and morbidity considerably [2]. Previous literature shows that the survival rate for non-traumatic cardiac arrest patients can be improved significantly through an onsite appropriate medical care [2][3][4][5][6][7]. A study by [8] concludes that 33% reduction in the probability of death can be achieved if the emergency medical response time is reduced by 10 minutes (25-15 minutes), in road side accidents.

GOALS AND OBJECTIVES
The goal of this research is to determine the utilization of current available resources of EMRS Peshawar. In any emergency medical response service, it is important to know the current utilization of the system (i.e. whether the EMRS system has enough resources) to efficiently respond to all the emergency calls and serve the location as per requirements.
Previously studies conducted for EMRS in Pakistan were

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To analyze the load on each station separately.

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To find out capacity of system, whether it can meet the current requirement or not.

Emergency Medical Services Operation Procedure
The process of intervention of an EMRS to an emergency site includes the following four steps: (1) incident detection and reporting to the EMRS control room, (2) call screening, (3) vehicle dispatching, and (4) actual intervention by paramedics [14]. The decision for dispatching the ambulance are to be made quickly by the emergency call operators for each incoming call [1] .

Decisions Needed to Address the EMRS Operations
The Simulation is now widely used in a broad spectrum of fields including but not limited to healthcare [15].
Because of the stochastic and dynamic nature of health care problems, discrete event simulation is used. Within the health care system, simulation is now been increasingly used in areas such as hospital bed capacity planning [16], emergency room settings [17], and patient flow and their waiting times. The simulation also addresses the issues such as the expense of maintaining the EMRS stations in places that will minimize the travel time to the site of incidence, improve the chances of patient survival, and keep the recurring cost within limits [18][19].
In Peshawar, KPK (Khyber Pakhtunkhwa) there is a greater need to re-assess the present EMRS stations that are located in and around the city, in the current prevailing situation, where the population has more than doubled since the last census in 1998.
According to last Census data [20], Peshawar was home

FIG. 1. FLOW CHART FOR THE CHAIN OF EVENTS LEADING TO INTERVENTION OF EMRS TO THE SITE OF INCIDENCE
The mission of the EMRS is "Timely, Professional and Scientific, response to any Emergency" [21]. This objective can be achieved by providing the proper medical care on time at the location of the incidents.
Hence, the success of EMRS system can be measured by the rapid and appropriate response provided at the site of the incident [22]. The EMRS has divided the city into seven zones, each zone being covered by one EMRS

Data Analysis
The call arrivals were plotted on histogram showing the average number of call arrivals at each hour in the 24hour period for the 90 days (Fig. 2).
The data was then fitted into a theoretical distribution.
Input analyzer, a module of Arena software is used to fit the theoretical distribution on data. The theoretical distribution shows the probability distribution, which the data is following, along with its parameters (Fig. 3). Then these parameters were put in the simulation model.
The data showed the Beta distribution with parameters of  1 = 1.1075 and  2 = 0.67136 for emergency calls arrival.
In addition, to check the reliability of the data, Kalmogorov Smirnov and Chi Square tests were performed.
The chi Square  2 statistics was calculated using the Where K is Number of Classes or intervals f oi is expected frequency for the class or interval i f ei is Expected frequency for the class or the interval i predicted by the theoretical distribution.
For the Beta distribution the  2 = 0.58332 The Kolmogorov Smirnov test was also performed for goodness of fit using the Equation (2). (2)

EMRS SIMULATION MODEL
The simulation model was developed in ARENA. First of all, the calls arrival was created for incoming calls reporting incident or emergency. If the operator line is available then it will receive the call otherwise the call will be rejected. The beta distribution was used for the inter-arrival call times and triangular distribution was deployed for operator call duration (the process of selecting the distributions is already explained before).
This process in simulation software (Arena) is shown in Fig. 5.  In Table 3 Table 4 shows the total number of emergency calls waiting in queue for ambulance availability. On the EMRS station 1 and 2 the average is relatively higher which is 0.311 minutes for each station. Still the waiting time for each call to be served by ambulance is less than a minute. The

Analysis of Emergency Medical Response Service in Peshawar through Simulation
The call waiting time and the operator utilization that recieves the call for each EMRS station is shown in the Tables 6-7.
The waiting time for each call being served by operator is shown in minutes.

CONCLUSIONS
In this study, we found out that all the seven EMRS are under-utilized and there is none calls waiting to be served. The low utilization of resources suggests that an awareness campaign be initiated among the local population that will increase the utilization of the stations.

FUTURE RESEARCH
It is suggested that further studies may be conducted while considering the variable speed of ambulances during rush and non-rush hours, actual population according to census with identification of thickly and thinly populated areas of the city.
This research study will help the community in several ways; optimization of the travel distance will reduce the response timer resulting in lives saves, it will also optimize the number of ambulances needed at each zone thus help in curtailing the EMRS stations budget and the study could be expanded and used in future in other towns as well with some minor modifications.