The single emergency number 911 (part 2)

In the USA and Canada, three digits are used for all emergency types. It may seem like a simple and effective system, but complexity lurks underneath.

Birth, operation and effectiveness of 911

911 (nine-one-one) is probably the best-known telephone number in the world. In the United States and Canada, these three digits are used to reach emergency services of all kinds. It sounds like a simple and effective system, but it may not always be so.

Article translated from the original Italian version

This article was written by Professor Nicolas Peschanski, who practices and teaches emergency medicine in France. There, the plans to establish the European single emergency number 112 are under much debate (1). While 911 is often cited as an example by advocates of adopting a single emergency number, few people know how the system is organized. The first part of the article recounts the origins of the number 911 and describes how it works. In the second part, Prof. Peschanski focuses on the administration of medical emergencies within the 911 system and reflects on the real effectiveness of using a single emergency number in France.

Go to part 1

Medical emergencies

The National Emergency Number Association (NENA) does not separately track national data by call type. It is therefore impossible to know on a national level how many 911 calls are made exclusively for medical emergencies, and how many calls go unanswered.

In some PSAPs, the first responder dispatcher performs both information gathering and dispatching, connecting directly with the medical (EMS) or fire department authorities. In other cases, information is relayed to a separate dispatcher through the computerized system. During this transfer of information, the first dispatcher terminates the call or remains on the line with the caller (3-way conference).

Emergencies that aren’t emergencies

Ambulance drivers and Emergency Medical Technicians (EMTs) or "paramedics" are expected to respond to medical emergencies. In the North American pre-hospital first aid system, however, these emergencies are defined by 911 callers rather than by telephone operators at PSAP centers.

In this diverse system, it is not easy to assess whether or not a person's medical symptoms justify a call to 911. Analysis of data from some PSAP centers shows that 15-20% of calls across all types are not emergencies. When considering only medical emergencies, this figure can be as high as 40%. However, as we have seen with calls involving police, the vast majority of 911 calls related to a medical emergency, real or perceived, result in an ambulance being dispatched by an EMS or fire station.

Effectiveness of dedicated channels

A defined assessment of the overall EMS system from call to hospital arrival does not exist. Only collaborative efforts organized locally or regionally by the medical directors of EMS agencies (who are physicians) can analyze specific types of interventions, such as cardiac arrest or gunshot wounds, for example.

For cardiac arrest, studies show very effective protocols in terms of the rate of spontaneous resumption of cardiac activity and mortality. The Seattle and King County EMS agencies in Washington State, both members of the Resuscitation Organization Consortium, show impressive results: 22% survival rate at hospital discharge and 56% for patients who received cardiac massage and defibrillation on arrival from the EMS. In Phoenix, Arizona, the Cardiac Arrest Registry to Enhance Survival (CARES) reports different statistics with 28.1% of patients arriving at the hospital alive and 10.8% leaving it alive.

There is limited retrospective data from self-reported questionnaires showing that nearly half of PSAP centers in the United States do not provide telephone assistance in performing BLSD maneuvers in the event of out-of-hospital cardiac arrest. Moreover, very few PSAPs even provide instruction in performing CPR. Studies indicate that there is significant potential to improve this critical link in the survival of cardiac arrest.

Is 911 an example to follow?

Evaluating the effectiveness of 911 has serious limitations. It is difficult to determine if current protocols are adequate and effective, especially the coding systems. Analyzing parameters other than response time would also be necessary. The structures that comprise the system are very heterogeneous, both in terms of organization and types of personnel and their level of training.

When they do exist, it is voluntary local policies that help streamline care processes. These policies are initiated by the medical directors of EMS agencies, who are physicians. They focus primarily on developing appropriate specific channels, effectively training staff, and optimizing the use of emergency services resources.

In my opinion, the example of 911 shows that in France a one-stop number scheme like 112 is not an ideal solution. Our ultimate goal is to continuously reduce call handling and response times. We will achieve this by steadily improving the efficiency of acute care channels, as developed by SAMU.


  1. There are four separate emergency numbers in France. Calls to 15 (Service d'aide médicale urgente - SAMU) are for medical emergencies only. 18 is the number for the fire department, which can also be called for medical emergencies. The number 17 takes callers to the police. Lastly, 112 calls are directed to either 15 or 18 depending on the geographic area. The idea of a single number is gradually gaining momentum. A trial in one region will begin in 2022. The fire department is in favor of this, but some emergency physicians are concerned that if the 15 number disappears, emergency services will lose their effectiveness.


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