Time Is On Emergency Dispatcher’s Side

Audrey Fraizer

Audrey Fraizer

Best Practices

Audrey Fraizer

A recent study should take the pressure off of EMDs who are often being pushed to achieve shorter call processing times. The study finds, in fact, that devoting more time to gathering case defining information up front actually reduces response times to the most critical calls and leads to better system efficiency and effectiveness.

Processing time is typically defined as the elapsed time from phone call pick up to responder unit notification.

“It’s not surprising that this research shows that giving emergency dispatchers sufficient time to do their job is better for the whole system,” said Greg Scott, Operations Research Analyst, International Academies of Emergency Dispatch® (IAED). “We’ve always advocated for doing it right above doing it fast, or too fast as is sometimes the case at dispatch.”

Janette Turner, Director of Health Services Research at the University of Sheffield’s Centre for Urgent and Emergency Care Research (East Yorkshire, England), led the Sheffield study to evaluate changes by National Health Service (NHS) England as part of the Ambulance Response Programme (ARP).

A major goal in the two-phase study was the development of initiatives to counteract increasing strain on NHS ambulance services while providing optimal patient care.


“There was a lot of inefficiency in the old system,” Turner said. “It [inefficiency] wasn’t the fault of the ambulance service. It was the target. So, we asked what could we do to improve while ensuring people in the most critical condition got the quickest response.”

Traditionally, emergency dispatchers in the NHS ambulance service 999 communication centers had up to 60 seconds to assess calls and establish the urgency of the problem and the type of response required. At this point the response-time clock started—a key performance measurement for ambulance services across the U.K. (e.g., eight minutes for the Red 1 code).

The urgency placed on meeting that response time performance measurement raised several issues, such as the tendency to send multiple vehicles to the same patient to meet the Red 1 and Red 2 time limits.

“For many years the main measure used to assess the quality of the ambulance service was how quickly an ambulance gets to a patient,” Turner said. “The ambulance response time targets were exacting and, over time, services were failing to meet them.”

Turner attributed several factors to an increasing inability in meet response time performance standards, including over-extended available resources, an overall increase in demand for ambulance services, and strong public expectations that put EMS in the position of evaluating performance according to how promptly they respond.

Two-phase study

The Sheffield study was divided into two phases, beginning in 2015.

Phase 1 involved changes to the triage of calls to allow more time for call handlers in cases that are not deemed as immediately life-threatening (Dispatch on Disposition, or DoD, which helps ensure resources are available to life-threatening situations when needed). The program was piloted in six ambulance services in England—London Ambulance Service (LAS), South Western Ambulance Service NHS Foundation Trust (SWAST), North East Ambulance Service, South Central Ambulance Service, West Midlands Ambulance Service, and Yorkshire Ambulance Service. The other four services continued to operate normally as control sites.

DoD is critical in the 999 clinical hubs, allowing additional time for triage of calls other than those that are most urgent. Ambulances are required to reach patients with life-threatening conditions (such as cardiac arrest) in a mean time of seven minutes, while additional time in dispatch is granted to decide the most appropriate response for patients not in immediate need.

Phase 2 involved the introduction of a new code set that has four key response categories, rather than three. In the former NHS system almost 50 percent of calls to ambulance services were classified as Red 1 or Red 2, requiring a response within eight minutes. Other calls were categorized as Green with local standards for response. In this phase, three services (SWAST, West Midlands, and Yorkshire) piloted the revised call categories.

In the categorization of calls, the Red and Green categories were eliminated in favor of the new code set established in phase 2 of the study2:

  • Category 1 (life-threatening calls): people needing treatment for life-threatening illnesses or injuries with response in an average of seven minutes (90th percentile of 15 minutes).
  • Category 2 (emergency calls): potentially serious conditions that might require rapid assessment, urgent on-scene intervention and/or urgent transport, with response in an average of 18 minutes (90th percentile of 40 minutes).
  • Category 3 (urgent calls): non-life-threatening problems that often can be managed at the scene, with 90 percent responded to within 120 minutes.
  • Category 4 (less urgent calls): problems requiring assessment either face-to-face or by telephone, with 90 percent responded to within 180 minutes.
An evaluation on the use of DoD following a six-month pilot period across six ambulance services in England reported a wide range of benefits from the trial to date, particularly the anticipated gains in ambulance service efficiency. Among these3:
  • DoD releases ambulance resource so that those most in need of an ambulance response have the right resource dispatched at the right time.
  • DoD improved Red 2 (8 minute) performance by between 2.5 percent and 2.9 percent. It also slowed the decline in Red 2 performance that is associated with steadily increasing demand.
  • It is clinically safe; the pilot evaluated 18 months of data from six pilot sites and compared it to four control sites, with 14 million 999 calls with no patient safety issues or harm arising.
  • Nature of Call successfully identified nearly three quarters of cardiac arrests (72.8 percent) as Red 1 calls, an increase from 64.8 percent in the earlier pilot period. 95 percent of all cardiac arrests were identified by a defined group of 10 descriptors.
  • Analysis suggests a maximum triage (DoD) time of 240 seconds, for all except Red 1 (now C1) calls where a clock start of T0 (“call connect”) should be retained.
  • DoD is supported by staff; both “control room” and operational “road” staff view the ARP as a positive step in helping to better manage emergency calls in a challenging environment.
Dispatch on Disposition is “intelligent dispatching,” Turner said.

“Dispatchers like having the extra time,” Turner said. “It allows them to do their job much better and manage resources more efficiently.”

The ARP’s Expert Clinical Reference Group unanimously recommended the extension of the DoD pilot to all NHS Ambulance Trusts, following the six-month evaluation. This decision was supported by the ambulance services, clinicians, and independent expert analysis, demonstrating a methodology and evidence base upon which to build further improvements.4 This was followed by implementing the new call categories in all services in July 2017 following approval by the Department of Health. These changes are the biggest initiated in ambulance service delivery for 40 years.

The study doesn’t stop here. Turner and her fellow researchers at Sheffield University are now at the point of filtering what they’ve already learned.

“We are getting to a place where we can better prioritize calls, and we want to take a closer look at MPDS® determinants to make sure people are aligned to the right category,” she said. “There will probably be more shifting around as we gather more evidence to refine the process.”

Time differences

The scrutiny of response times has picked up steam over the past few years, particularly in the U.S. following recommendations of the National Fire Protection Association (NFPA). In the 2010 edition of NFPA 1710, the following was added: “The travel times for units responding on the first alarm were clarified to indicate the first unit must arrive within 4 minutes’ travel time and all units must arrive within 8 minutes’ travel time.”5 In keeping with the theme of rapid response, the NFPA has a separate time standard for dispatch (call processing) times—NFPA 1221 which requires a 90 second call processing time (in 90 percent or more of all cases) for most medical emergency calls.5

Several studies before and after NFPA 1710 was issued have indicated that the eight-minute response time is not a valid standard performance measurement. For example, a study published at about the same time as NFPA 1710 reviewed the “pitfalls” of response time (RT) as a sole performance indicator.6 The article drew similar drawbacks: lack of evidence supporting the validity of RT as a performance indicator; using RT gives an undeserved sense of high performance and dominates over the patient quality care; and, finally, aiming to meet RT standards induces financial and safety costs.7

“It all starts in dispatch,” Turner said. “We conducted the study in a very controlled way and found Dispatch on Disposition safe and efficient. It improves response and care for the patient overall. While it took some time for them to get used to it, they’d never go back to the old way.”

Note: The IAED was not included in the study. MPDS was represented on the clinical subgroup that reviewed the call categories and allocated MPDS determinants to each category.


1Turner J (et al.). “Ambulance Response Programme. Evaluation of Phase 1 and Phase 2.” 2017; July 13. https://www.england.nhs.uk/wp-content/uploads/2017/07/ARPReport_Final.pdf (accessed July 13, 2018).

2Quaile A. “What’s next for England’s ambulance services?” 2017; Nov. 23. https://aliquaile.com/tag/dispatch-on-disposition/ (accessed July 24, 2018).

3Dunne P. “Ambulance Response Programme Evaluation Report on Dispatch on Disposition.” 2016; July 20. https://www.england.nhs.uk/wp-content/uploads/2016/04/letter-dod-amb-response-prog.pdf (accessed July 25, 2018).

4See note 3.

5“Understanding NFPA 1710 Response Times.” Purvis Systems Public Safety Division. 2014; Oct. 18. http://purvispublicsafety.com/2014/10/18/nfpa-1710-response-times/ (accessed July 13, 2018).

6Khalifah Al-Shaqsi SZ. “Response time as a sole performance indicator in EMS: Pitfalls and solutions.” Open Access Emergency Medicine. 2010; Jan. 8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806820/ (accessed July 25, 2018).

7See note 6.