Dynamic deployment: 5 more persistent myths busted
The implementation of dynamic deployment and how it is different from system status management is explained in this second myth busting primer
By Dale Loberger
Dynamic deployment of ambulances is an evolving topic in EMS. Dynamic deployment: 5 persistent myths provided a basic definition for dynamic deployment, how it is different than System Status Management and what it means for response to calls in rural areas.
To correct some of the other concepts about dynamic deployment that I often see confused in discussions and articles about it, here are five more of the most common misconceptions and the current reality behind each statement.
Myth 1: A hybrid model works better for us than a full dynamic deployment strategy
There are EMS agencies with only a vehicle or two that cover a relatively small service area that are genuinely better served by a static deployment from a centrally located station. However, once a threshold of demand, available resources, and traffic congestion is reached that allows calls to be accurately forecast and where response times can be reduced by moving vehicles out of their stations, a deployment model that moves resources from the station to temporary posting locations is warranted.
Dynamic deployment regularly forecasts demand and disperses resources in order to address those next most likely calls with consideration given to fluctuating traffic patterns such as morning rush hour, afternoon school dismal or other special events. The idea of only partially implementing this strategy is an admission that the concept either does not work or is not yet needed. The justification for a hybrid implementation is that some resources need to be kept in reserve at certain geographic locations because the demand is uncertain. A true hybrid model is a partial implementation of competing strategies rather than a single, unique cooperative plan. Balancing unique geographic constraints is better managed through weighting response objectives than by dividing the response strategy.
Myth 2: Dynamic deployment is all about chasing response times
While the most widely touted benefit of dynamic deployment is an improvement in response time, it is clearly not the only benefit. Dynamic deployment closes the distance an ambulance travels between the point of its dispatch and its arrival on scene. The most dangerous time to be in an ambulance is when it is traveling under red lights and siren. The shorter the distance a vehicle is required to travel; the safety of the crew in that ambulance potentially improves.
An additional benefit of moving vehicles closer to the calls is reducing the miles driven as measured in the operational savings experienced. These savings are compounded when the specific portion of non-reimbursed miles is reduced.
Myth 3: The foundation of dynamic deployment is predicting completely random accidents
The nature of calls for EMS is certainly dynamic, but it is far from random. Much like forecasting the weather, calls for service follow identifiable patterns. No one can claim to know which phone is about to dial 911; however, the likelihood of a call originating in an identifiable area can be accurately forecast and responded to accordingly.
A simple test for the potential of forecasting calls can be made by comparing call volumes from previous years. When a pattern can be discerned between years, it can also be interpolated between much shorter time segments. The natural groupings of demographics and consistencies of traffic patterns are just a few of the parameters that conspire to create useful demand forecasts.
Myth 4: Since our ambulances are constantly on the road, we already have a dynamic deployment
Every EMS system has units moving around the service area at some point during each shift. Even a static, station-based plan will have ambulances in the field at some point when a call is received. The core strategy, however, is identified by the planning for how those resources are deployed.
System Status Management dictates 168 plans each week for every possible service level to address the changing densities of demand each hour and the available resources to address them. Dynamic deployment is unique in that it constantly varies the deployment pattern specifically to address forecast demand in near real-time so that the number of potential plan options is effectively infinite.
By contrast, any system that operates with a single posting plan based strictly on the number of available resources is the technical equivalent of a static plan similar to staffing fire stations where resources are redeployed as move-ups. The deployment strategy has nothing to do with whether the crews are reclining in a station lounge or sitting in the ambulance cab. The only difference is that crews waiting in the ambulance will have a reduced chute time to improve response.
Myth 5: Our service does not need to consider a dynamic deployment strategy
While there may not be any magic in an eight-minute response goal or even any gold in the platinum ten minutes, dynamic deployment as a strategy is not designed to hit a specific time target. The objectives for employing a dynamic deployment strategy are to reduce the drive time, the emergency driving distance and to shorten patient wait times. These objectives translate to values in improving safety, response, and patient satisfaction within the limited financial and resource constraints of most EMS systems.
- Stout, Jack L. (1983 May 22) System Status Management: The Strategy of Ambulance Placement. JEMS.
- Ingolfsson, A. (2013). EMS Planning and Management. In Operations Research and Health Care Policy (pp. 105-128). Springer New York.
- Dean, Stephen S. Why the Closest Ambulance Cannot be Dispatched in an Urban Emergency Medical Services System. Prehospital and Disaster Medicine, 2008, 23, pp 161-165
- Ward, Michael J. (2012 October 18) How Fire Departments Mangle Ambulance Deployment. EMS1.
- Brophy, John R. (2014). Dynamic Deployment: A Primer for EMS. Createspace. Charleston, South Carolina.
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