Emergency Medical Services

Brad l ey L. Demeter, MD

Eric H. Beck, DO

Key Points

• Emergency medical services (EMS) is the extension of

emergency medical care into the prehospital setting.

• The u.s. EMS Systems Act of 1 973 established key

elements for EMS systems to receive funding.

INTRODUCTION

Emergency medical services (EMS) is the medical specialty

that involves the delivery of prehospital care. The use of the

term "EMS" may refer solely to the prehospital element of

care or be part of an integrated system, including the main

care provider, such as a hospital.

Federal funding for emergency medical services came

with the U.S. EMS Systems Act of 1 973, which established

15 key elements that must be addressed by systems to

receive funding. The elements are used here as an outline

for discussion.

..... Manpower

The workforce providing prehospital care varies largely

based on population density. Urban areas typically have

paid providers serving through government agencies or as

public safety officers in large public venues (airports,

amusement parks, etc). Volunteers are more commonly

found in suburban, rural, and wilderness areas.

..... Training

The U.S. Department of Transportation (DOT) National

Highway Traffic Safety Administration (NHTSA) National

Standard Curriculum for prehospital care providers historically outlined 4 levels of training: first responder, EMTbasic, EMT-intermediate, and EMT-paramedic. Currently,

• In 201 2, the American Board of Medical Specia lties

approved EMS as a subspecialty.

these levels are being transitioned to 4 nationally standardized levels of certification: emergency medical responder

(EMR), emergency medical technician (EMT), advanced

EMT (AEMT), and paramedic. Each level of training infers

a specific role, skill set, and knowledge base (Table 9- 1).

EMS provider training at all levels emphasizes airway,

breathing, and circulation (ABCs) and provider scene

safety as priorities in patient care. Although significant

efforts have been made to standardize education and certification throughout the United States, variability exists

from state to state in scope of practice and specific medication usage by each level of prehospital provider .

..... Communications/ Access to Care

In the early 1970s, "9-1-1" became the now ubiquitous

common point of access to emergency services. Call cen ­

ters are typically staffed by trained dispatchers who practice priority dispatching. Their job is to gather sufficient

information to triage and allocate the most appropriate

resources for a given response. It is becoming increasingly

common for dispatchers to provide pre-arrival

instructions to the caller, such as how to perform

layperson CPR.

..... Transportation

Transport vehicles vary in equipment based on the

intended response model and provider scope of practice.

30

EMERGENCY MEDICAL SERVICES

Table 9-1 . Prehospital care providers.

Certification Level Description

Emergency medical responder (EMR} The first responders to arrive on scene, they are trained to perform immediate lifesaving care with limited

resources until additional EMS responders arrive. Their skill set includes CPR, spinal immobil ization, oxygen administration, hemorrhage control, and use of an automated external defibrillator (AED}.

Emergency medical technician (EMT) This is the basic level of training necessary for ambulance operations. EMTs' skill set includes that of the

EMR, with the addition of transport operations and the assistance of patients in taking some of their

own prescription medications, such as metered-dose inhalers or nitroglycerine tablets. They may also

provide several medications including oral glucose, aspirin, albuterol, and epinephrine for anaphylaxis.

Advanced emergency medical

technician (AEMT}

Under medical direction, the AEMT may initiate intravenous or intraosseous access, perform manual defibril lation, interpret electrocardiograms, and administer an expanded range of medications.

Paramedic Traditionally the highest prehospital level of training with the broadest scope of practice. Their expanded

skill set includes endotracheal intubation, cricothyrotomy, needle thoracostomy. Drug administration

includes vasoactive agents, benzodiazepines, and opiates for pain control. They are also trained to perform higher level ECG analysis and to provide antiarrhythmic therapy with medications, electrical cardiaversion, manual defibrillation, and transcutaneous pacing.

Critical care paramedic This is a provider level that reflects additional training, knowledge, and scope of practice that is needed

for initiating or maintaining advanced level intervention during transport. Critical care paramedics often

have training in chest tube placement and management, balloon pump management, neonatal care,

central venous catheters, arterial lines, and hemodynamic monitoring. Additional medications including

neuromuscular blockers and sedation agents are commonly used at this level of care .

Basic life support ( BLS) ground units have automated

external defibrillators (AED) and supplies necessary for

basic wound care and airway management, including

oxygen, bag-valve-masks, suction equipment, and oral

and nasal airways. Advanced life support (ALS) units

have equipment necessary for a paramedic's scope of

practice, including equipment for IV access, medications,

and a cardiac monitor/defibrillator for rhythm analysis

and intervention. Some systems have uniquely equipped

critical care transport units that are designed to

accommodate patients with continuous IV infusions,

ventilators, or other specialized medical equipment such

as intra-aortic balloon pumps or neonatal incubators.

Air medical transport comprises both fixed-wing

(airplane) and rotary-wing (helicopter) vehicles. General

indications for air medical transport are outlined in

Table 9-2.

Table 9-2. Relative indications for air medical transport.

Distance by ground to the closest appropriate medical facil ity is too

great for safe and timely transport.

A delay during ground transport would likely worsen the patient's

clinical condition.

Special ized care is not available from local ground response

agencies.

An area is inaccessible to ground traffic.

The use of local ground resources would leave an area temporarily

without adequate resources.

.,..._ Facilities/Critical Care Units

In general, prehospital patients are transported to the closest appropriate medical facility. There are some situations

in which a patient's preference may dictate hospital desti ­

nation. One issue that has emerged as a product of hospital

overcrowding is ambulance diversion, where ambulances

may need to bypass the closest appropriate facility to transport to another center that has capacity. Another factor in

hospital destination is availability of specialty care for

time-critical diagnoses. Examples of field triage and transport for time-critical illnesses include designated "trauma

centers;' facilities with surgical teams and operating rooms

on standby; "stroke centers;' with immediately available

neurology and neurosurgical capabilities; and "cardiac

centers;' with cardiac catheterization laboratories and

therapeutic hypothermia resources readily available for

patients with acute coronary syndromes or cardiac arrest.

Obstetrical, pediatric, and burn centers are recognized in

some regions as specially designated receiving facilities.

.,..._ Public Safety Agencies

Prehospital responses are often coordinated efforts between

police, fire, and EMS personnel. Various paradigms for the

division of labor within a given municipality exist. Some of

the more common EMS structures include fire-based,

third-service, private, and hospital-based. Fire-based

ambulances are staffed and operated by the local fire

department, whereas in third-service systems, EMS are

separate from both police and fire departments. Private

ambulance companies may provide nonurgent transports

CHAPTER 9

or may operate under contract with local governments to

supplement or provide all emergency care for a municipality. Lastly, hospital-based ambulances have crews of

hospital-employed personnel dispatched on ambulances

owned by the hospital.

..... Consumer Participation/Public

Information and Education

An important aspect of most EMS operations is community service, ranging from public relations expositions to

educational initiatives like CPR training. It is also common

for public representatives to participate in the oversight

and decision making that takes place within a public EMS

organization. EMS is often described as existing at the

intersection of public safety and public health; EMS data

and personnel are a critical link in public health infrastructure and preventative interventions.

..... Patient Transfer

One of the primary purposes of EMS is to deliver patients

to the care that they need. In many cases, this involves

transport from the scene of an injury or medical event to a

receiving hospital, but it may also involve the transport of

a patient from one medical facility to another. A key legislative mandate set forth in the Emergency Medical

Treatment and Active Labor Act (EMTALA) is that an

appropriate medical screening exam must be performed to

identify emergent medical conditions that must be stabilized before a patient can be considered for transfer to

another facility. Receiving hospitals must explicitly accept

a transfer before a patient is transported.

..... Coordinated Patient Record Keeping

T�e method of charting varies from one system to another,

W1th many systems now implementing an electronic medical record. A significant barrier to prehospital research is

the tremendous variation that exists in charting methods,

data definitions, and reporting requirements. There is also

difficulty linking prehospital data to hospital or outcomes

data.

..... Review and Evaluation

The care rendered by prehospital providers is overseen by a

physician medical director. Day-to-day operations generally

function using either "standing orders" (offline medical

control-protocols developed to guide patient care) or

online medical control (real-time telephone/radio communication with hospital personnel to answer clinical questions

or to receive orders). Protocols undergo periodic review for

updates based on changing system needs and current science. Proactive systems have robust continuous quality

Table 9-3. The "Simple Triage and Rapid Treatment"

(START) system.

Green (minor)

Yellow (delayed)

Red (immediate)

Black (deceased)

Care may be delayed (eg, non-l imbthreatening extremity trauma)

Will require urgent care (eg, hemorrhage

with signs of adequate perfusion)

Requires immediate care for life-threatening

injury (eg, severe hemorrhage or airway

compromise)

Either dead or mortally wounded, such that

dedication of any additional resources is

unl ikely to alter outcome

improvement processes, by which EMS data are used to

identify areas of the system in need of improvement .

..... Disaster Plan/Preparedness

Emergency response plans exist at local, state, and national

levels. Key features include provisions for interagency

communication and agreements regarding the optimal

allocation of limited resources when a system's capacity is

exceeded-a situation referred to as a mass casualty incident. In these situations, the "Simple Triage and Rapid

Treatment" (START) algorithm is a commonly employed

triage protocol used to assess severity of injury and to

assign transport priority. Providers assign 1 of 4 colors to

victims during an initial assessment focused on the ABCs

(Table 9-3).

..... Mutual Aid

Agreements among neighboring municipalities or EMS

services are common to bolster the capacity of a given

agency's emergency response system. Interagency communication and equipment interoperability are potential

challenges that need to be addressed in establishing such

relationships.

SUGGESTED READING

Emergency Medical Services: Clinical Practice and Systems

Overstght. National Association of EMS Physicians. Dubuque,

IA: Kendal/Hunt, 2009.

Mechem CC. Emergency medical services. ln: Tintinalli JE,

Stapczynsk.i JS, Ma OJ, Cline DM, Cydulka RK, Meckler GD.

Tintinalli's Emergency Medicine: A Comprehensive Study

C!utde. 7_th ed. New York, NY: McGraw-Hill, 20 l l, pp. l-4.

NatiOnal Highway Traffic Safety Administration. The National EMS

Scope of Practice Model. DOT HS 810 657. Washington, DC:

National Highway Traffic Safety Administration, 2007.