Critically injured patients must receive high-quality care from the earliest post-injury moment to have the best chance of survival. Most trauma victims first receive health care from the emergency medical services (EMS) system, which is responsible for rendering aid and transporting the trauma patient to an appropriate facility.

The practice of medicine in the prehospital setting presents numerous challenges not encountered in the hospital. Hazardous materials along with environmental and climatic conditions may pose dangers to rescuers as well as to patients. If the patient is entrapped in a mangled vehicle or a collapsed building, there must be meticulous coordination of medical and rescue teams. Providers of prehospital care are expected to deliver high-quality medical care in situations that are austere and unforgiving and, often, for prolonged periods.

The role of the EMS system is far more complex than simply transporting the trauma victim to a medical facility. In most EMS systems in the United States, specially trained health care professionals are responsible for the initial assessment and management of the injured patient. Experience from the last several decades has shown that these paraprofessionals can safely perform many of the interventions that were previously performed only by physicians or nurses in the emergency department.

While many of these procedures have proven beneficial for victims of cardiac emergencies, critically injured patients may need two items not usually available on an ambulance—blood and a surgeon. As EMS systems mature and additional prehospital care research is conducted, the question is no longer, “What can the Emergency Medical Technician (EMT) do for the trauma patient in the prehospital setting?” but rather, “What should the EMT do?”

While the roots of prehospital trauma care can be traced back to military physicians, modern civilian prehospital trauma care began about four decades ago. J.D. “Deke” Farrington and Sam Banks instituted the first trauma course for ambulance personnel in 1960.¹ This course, initiated with the Chicago Committee on Trauma and the Chicago Fire Academy, marked the beginning of formal training in prehospital care of injured patients. Farrington is generally acknowledged as the father of modern EMS.²

In September, 1966, the National Academy of Sciences and National Research Council published the landmark monograph, Accidental Death and Disability: The Neglected Disease of Modern Society.³ This document argued that there were no standards for ambulances with respect to design, equipment, or training of personnel. As a direct result of this monograph, the Department of Transportation funded the development of the Emergency Medical Technician–Ambulance (EMT-A) curriculum, which was published in 1969. Continued public pressure resulted in the passage of the Emergency Medical Services (EMS) Systems Act of 1973 (PL 93-154). This act revolutionized EMS in this country and resulted in federal funding for the establishment of EMS systems.

In the late 1950s, Pantridge, an Irish physician practicing in Belfast, developed a mobile coronary care unit that was staffed by physicians.⁴ He conceived of a system in which the victim of an acute myocardial infarction was stabilized at the scene by bringing advanced life support (ALS) to the patient. The physicians worked to restore normal cardiac rhythm through medications and defibrillation at the location where the victim was stricken.

In the United States, the concept of advanced prehospital care involved training emergency medical technicians (EMTs) to perform these lifesaving skills. The original “paramedic” programs began in Los Angeles, California; Houston, Texas; Jacksonville, Florida; and Columbus, Ohio and were often associated with fire departments. Paramedics were trained to serve as the “eyes and ears” of the physicians in their base hospitals and provide care under their direction.

While prehospital ALS proved beneficial for victims of cardiac emergencies, it was not until the 1980s that it became obvious that definitive care for trauma patients was fundamentally different than that for the cardiac patient. Efforts to restore circulating blood volume proved to be unsuccessful in the face of ongoing internal hemorrhage. The exsanguinating trauma patient requires operative intervention, and any action that delays the trauma patient’s arrival in the operating room is ultimately detrimental to survival. During this period, significant controversy surrounded prehospital ALS for trauma patients as expert panels and editorialists debated its pros and cons.^5,6 Several studies documented the detrimental effect of prolonged attempts at field stabilization on seriously injured trauma patients,^7,8,9 while others showed that paramedics could employ ALS measures in an expeditious manner.^10,11,12,13

The modern EMS system involves the integration of a number of complex components. Essential elements include the following: personnel, equipment, communications, transport modalities, medical control, and an ongoing quality improvement process. Different configurations of EMS systems result when these components are integrated in varying combinations. The EMS system represents a significant component of the trauma system, described elsewhere (see Chapter 4).

The Department of Transportation, through the EMS office of the National Highway Traffic Safety Administration, provides federal leadership for the EMS system. With input from national stakeholder organizations, NHTSA developed the EMS Agenda for the Future, published in 1996.¹⁴ This document detailed a vision for improving 14 aspects of EMS including the following: integration of health services, EMS research, legislation and regulation, system finance, human resources, medical direction, education systems, public education, prevention, public access, communication systems, clinical care, information systems, and evaluation. Two related documents that expand on concepts addressed in the original Agenda are the EMS Education Agenda for the Future: A Systems Approach (2000) and the National EMS Research Agenda (2001).^15,16

EMS Personnel

EMTs comprise the vast majority of prehospital care providers employed in the United States, and only a small number of nurses and physicians deliver care in the out-of-hospital setting.

Emergency Medical Technicians

For more than a decade, the National Emergency Medical Services Education and Practice Blueprint, published by NHTSA in 1993, provided the basis for the levels and training of EMTs utilized in the United States.¹⁷ The four levels of EMTs described in the document are the First Responder, EMT-Basic, EMT-Intermediate (EMT-I), and EMT-Paramedic. An enhanced EMT-I level was introduced in 1999, but many states retained the original 1985 curriculum. The Blueprint divided the major areas of prehospital instruction into 16 “core elements.” For each core element, there are progressively increasing knowledge and skill objectives, representing a continuum of education and practice. A National Standard Curriculum (NSC) provided lesson plans for each level.

With the publication of the EMS Education Agenda for the Future, the foundation was laid to replace the NSC with a system that would hopefully standardize EMS training and certification across the country. This system is based on a medical model that includes a defined scope of practice, accredited education programs, certifying exams that ensure baseline competency, and licensure to permit one to practice. Three of the five components of this system focus on the levels and education of EMS providers, and each had input from national stakeholder organizations and the public during its development.

National EMS Core Content

Published in 2005, this document describes the domain of prehospital care, identifying the universal body of knowledge and skills that could potentially be utilized by EMS providers who do not function as independent practitioners.¹⁸

National EMS Scope of Practice Model

Published in 2007, this document identifies four new levels of prehospital care practitioners¹⁹ (Table 7-1). The knowledge and skills described in the Core Content are divided among the four levels. During the development of the Scope of Practice Model, there was insufficient support in the EMS and medical communities to support the development of a fifth level of EMS provider with a scope of practice greater than that of the paramedic.

National EMS Education Standards

Published in 2009, these standards describe the minimal, entry-level competencies that EMS personnel must achieve for each of the levels described in the Scope of Practice.²⁰ Compared to the NSC, the Education Standards allow for more diverse methods of implementation, more frequent updates of content, and some variation at the state or local level. Each level builds upon the knowledge and skills of the previous level.

The four levels of prehospital care providers described in this new system are described below.

Emergency Medical Responder

This level was previously named “first responder” (FR). Following the terrorist attacks of September 11, 2001, this term now refers to those who are the initial responders to emergencies and could include law enforcement personnel or firefighters who may lack medical training. The emergency medical responder (EMR) uses a limited amount of equipment to perform initial assessment and rudimentary intervention until EMS providers with a higher level of training arrive at the scene. Skills utilized by the EMR include oral airways, suctioning, automated external defibrillators, cardiopulmonary resuscitation (CPR), oxygen therapy, hemorrhage control, and manual stabilization of the spine and injured extremity. New skills included at the EMR level that were not taught to the FR include measurement of blood pressure, eye irrigation, and use of a bag-valve mask (BVM) device and auto-injectors for self or peers.

Emergency Medical Technician

Previously termed the EMT-Basic, the emergency medical technician (EMT) has greater knowledge and skills than the first responder and holds the minimum qualifications to staff an ambulance. The EMT possesses expanded assessment skills and is trained to perform spinal immobilization and splinting, assist with uncomplicated childbirth, and use limited medications (oral glucose, sublingual nitroglycerine, and subcutaneous epinephrine). Compared to the EMT-Basic, the new EMT is trained to use more types of oxygen masks, automated transport ventilators, auto-injectors, and oral administration of aspirin.

Advanced EMT

In the current system, the EMT-I is the least well defined of all the levels of EMS providers, as training requirements and skills vary widely from state to state. The advanced EMT (AEMT) replaces both versions of the EMT-I; although the AEMT is closer to the scope of practice of the 1999 EMT-I than to the 1985 version. Additional time is devoted to acquiring a more in-depth knowledge of pathophysiology, advanced techniques of patient assessment, and advanced skills for airway management, but not endotracheal intubation. The AEMT is trained in intravenous access and can perform fluid resuscitation with crystalloid solutions. Medications an AEMT may administer include epinephrine, glucagon, 50% dextrose, naloxone, and inhaled β-agonists and nitrous oxide.

Paramedic

In addition to the knowledge and skills of the previous levels, the paramedic is trained in the use of a wider range of medications and the performance of a greater number of advanced skills. The scope of practice of the EMT-Paramedic includes endotracheal intubation, needle decompression of the pleural cavity, cardiac monitoring and interpretation of arrhythmias, and administration of numerous medications. The paramedic has had a major impact on the resuscitation of patients with cardiac or major medical problems and is very effective in urban areas in which response times are short. Compared to the EMT-Paramedic, the new paramedic is trained to administer continuous positive airway pressure (CPAP), monitor and manage chest tubes, access indwelling venous devices, perform eye irrigation using a Morgan lens, initiate and monitor thrombolytic agents, and perform analysis of limited blood chemistry utilizing portable devices.

Education and Certification of EMS Personnel

In addition to the three components of the EMS Education Agenda for the Future described above, the two additional elements that complete this system of EMS education are national certification and national accreditation of paramedic training programs.

National EMS Certification

In medical practice, certification exams serve to protect the public by ensuring that practitioners have minimal, entry-level competency on entering the workforce. Traditionally, individual states have offered certification exams for their EMS personnel, but this results in issues related to cost for test development, legal challenges, and reciprocity as EMS providers move from one state to another. The National Registry of EMTs (NREMT), a nonprofit organization founded in 1970, has emerged as the only national entity that offers certification exams for all recognized EMS levels. Through its careful test development, NREMT offers psychometrically sound, legally defensible examinations that states may use for licensure of their EMS personnel. Currently,²¹ states utilize the NREMT examination process.

National EMS Education Program Accreditation

The Committee on Accreditation of EMS Programs (CoAEMSP), also a nonprofit corporation, is the only organization that offers accreditation of paramedic training programs on a national basis. CoAEMSP itself is accredited by the Commission on Accreditation of Allied Health Education Programs (CAAHEP). Established in 1994, this group had its origins as the Council on Medical Education of the American Medical Association. CoAEMSP utilizes a combination of self and peer assessment to a set of defined standards that ensure a quality educational experience for the student. One recent study demonstrated that graduates of accredited paramedic programs are more likely to successfully achieve certification by the NREMT.²² The NREMT now requires applicants for the paramedic certification exam to have graduated from an accredited education program.

Nurses

Nurses occupy a unique position in the EMS system. They serve as prehospital providers, instructors, and proctors of quality improvement. While nursing education imparts an excellent understanding of patient assessment, the pathophysiology of disease processes, and administration of medications, most nursing programs do not teach many of the skills necessary for prehospital care. These include splinting, spinal immobilization, and advanced airway management, so dual training is often required to function in the EMS setting. Nurses may also be employed by EMS services as on-site instructors for continuing education and may be utilized as field observers for quality improvement. They can provide insight to the EMTs on the smooth integration of patient care from the field to the emergency department.

Ground Nurses

When dual trained as a nurse and an EMT, the individual can function in the field as a prehospital provider under the auspices of EMT certification. Nurses are utilized by many critical care transport services to assist in the care of special patients (eg, neonatal and cardiac). In this context, nurses can function to the extent of their training, abilities, and license restrictions. Most states have not developed standards for the prehospital role of nurses. Because of the paucity of trained EMTs, nurses often serve as ambulance attendants in foreign countries.

Flight Nurses

Almost all air medical services in the United States utilize nurses in the delivery of prehospital care and transport. The composition of the flight crews varies widely, and common configurations are two nurses, a nurse and a paramedic or EMT, or a physician with either a nurse or paramedic, while some services fly a nurse with a respiratory therapist. The scope of practice of both the critical care nurses and the paramedics during critical care air or ground transports varies widely from state to state based on nursing law and state EMS regulations, as well as delegation of skills by authority of medical direction. Approximately two-thirds of helicopter medical services in the United States utilize a combination of a critical care nurse paired with a paramedic. This combination of disciplines provides a wide range of complementary knowledge and skills between the two providers in caring for both out-of-hospital scene flights, which are predominantly for victims of trauma and the complex patients transported from one hospital to another.

Physicians

In the United States, it is unusual for physicians to directly participate in the provision of care to the injured patient in the field, although about 5% of air medical services utilize physicians as members of their primary flight crew. The physicians assigned to such crews are usually emergency medicine residents who rotate onto the aircraft as a formal part of their residency. Another use of physicians in the prehospital setting involves neonatologists or pediatric residents or fellows who staff units used for interfacility transport of critically ill infants.

In Europe, Australia, New Zealand, Japan, Central and South America it is common for physicians to function as primary members of the EMS team. Because of a surplus of physicians or a lack of attractive employment opportunities, physicians may work for an EMS service, either staffing an ambulance or responding in a separate vehicle. The standards of EMT training in the United States suggest that little is gained by employing physicians on EMS units, and this use of a valuable resource in the field is a challenging one to defend.

Physicians who happen upon the scene of a motor vehicle crash may be tempted to assume control of the patient despite the fact that they possess little experience caring for patients in the prehospital setting. In such situations, the physician should realize that the vast majority of EMTs are well trained and capable of performing their job and that they work under the medical direction of a licensed physician. Additionally, should the physician begin to direct care for a patient, he or she must remain with the patient until care is formally transferred over to an accepting physician, either by radio communication or by face-to-face turnover in the emergency department. Failure to do so may constitute abandonment of the patient and leave the physician exposed to serious legal repercussions.

Longer range air transports of critical trauma and medical patients by physicians and nursing staff has been refined by the United States Air Force Critical Care Air Transport Teams (CCATT) with positive effect on morbidity and mortality.^23,24

Prior to the early 1970s, EMS services in the United States were very rudimentary and focused primarily on transportation of patients. Actual medical care began only after the patient’s arrival at the hospital. Today, numerous models of EMS systems exist, as the various elements of the system are combined in different ways. No definitive evidence exists that one model is superior in performance to any other, and community leaders design their system around the available resources in the community. An EMS service may be operated by a private company, a hospital, a fire department, a police department, or an agency funded by the government that is solely responsible for emergency medical care (a public “third service”). Regardless of which agency provides EMS, prehospital care generally fits into one of two distinct categories—basic life support (BLS) and ALS.²⁵

Basic Life Support

BLS is a term used to describe a level of care that provides noninvasive emergency care and includes care rendered by personnel trained at the EMR and EMT levels. While EMRs may drive an ambulance, the minimum level for providing patient care during transportation should be the EMT. BLS involves providing basic airway management, supplemental oxygen, and rescue breathing; CPR; control of external hemorrhage; splinting; spinal immobilization; and uncomplicated childbirth. The goal of BLS care is to maintain breathing and circulation and transport the patient without causing further harm. Many BLS services utilize semi-automatic external defibrillators (AEDs) that identify ventricular fibrillation and deliver electrical countershocks. Because of the limited equipment and training, BLS systems are less costly to establish and maintain than are more advanced levels of care.

Advanced Life Support

ALS describes care that involves the use of more advanced, invasive procedures such as those performed by personnel in an emergency department. EMS providers at the ALS level are capable of advanced airway management, cardiac monitoring, cardioversion and defibrillation, insertion of intravenous lines, and administration of numerous medications. ALS systems utilize individuals trained at the AEMT or paramedic level.

In contrast to BLS systems, ALS systems provide advanced therapy to the patient at the scene, rather than waiting until arrival at a hospital to institute care. ALS systems have had impressive results in the care of cardiac patients, especially when CPR is started within 4 minutes of a cardiopulmonary arrest and ALS can be initiated within 8 minutes of the arrest. These types of systems, however, are very expensive to establish and maintain, primarily because of the equipment and amount of training required. ALS systems also must invest more in continuing education for their personnel in order to maintain their skills.

Tiered Response Systems

An EMS system that is not purely BLS or ALS but a combination of both is called a tiered response system.²³ The goal of a tiered EMS system is to match the training level of the provider with the needs of the patient. The first level of care is typically BLS with the providers being from a public safety agency (eg, fire or police) or EMS units staffed by EMTs. In this model, BLS personnel would initiate transport if the patient did not require ALS procedures. If ALS interventions are needed, the BLS crews initiate basic care and attempt to stabilize the patient until the ALS unit arrives. This allows ALS units to respond only when needed.

Proponents of this system argue that it functions in a more cost-effective manner, providing ALS-level care only to those patients who require it. In many communities, especially those in rural settings, a third tier comprised of air medical transport may be utilized. This tier usually provides a slightly higher level of training and expertise, combined with the more rapid transport capabilities of the aircraft. The structure of the system will vary widely based on local geography, population density and resources, but must be set up by local consensus in the region in conjunction with the state(s) involved.

The American College of Surgeons Committee on Trauma (ACSCOT) joined with the American College of Emergency Physicians (ACEP), the National Association of EMS Physicians (NAEMSP), and other organizations to publish a document delineating the necessary equipment that should be stocked on an EMS unit.²⁶ This document includes separate recommendations for both BLS and ALS ambulances. The most recent revision requires EMS units to include sufficient sizes of equipment to adequately care for infants and children in addition to adults. In most jurisdictions, state law mandates the equipment carried by EMS units, and administrative agencies periodically inspect ambulances to ensure that necessary equipment is present. Medical directors may also require that certain equipment or medications be added to units under their direction.

Communications comprise an essential component of the EMS system. The EMS dispatch center must be able to readily locate the unit closest to the incident and provide them with an exact location and description of the call. EMS units must also be able to communicate with other agencies that provide first responder care (ie, law enforcement and fire department) and those that serve an adjunctive role such as extrication and control of hazardous materials. EMS units must also have two-way communication with receiving facilities and with the physicians who provide medical oversight. EMS personnel may request specific orders from a physician when a patient’s condition falls outside established treatment protocols. The increased availability of public safety answering point (PSAPs) and EMS dispatch centers to automatic notification of a crash information may enhance their ability to send appropriate response to an traumatic event.^27,28

Ground Units

EMS units operating on the ground may possess transport capabilities (ie, an ambulance) or they may be a “quick response” unit that contains only equipment and personnel, and a separate ambulance is required for transport. Such quick response vehicles are common in rural areas or in tiered EMS systems. Ambulances should conform to size and performance specifications as outlined by governmental agencies and authoritative organizations and possess required equipment as described earlier.

In areas primarily covered by BLS units, a tiered response arrangement should be in place so that ALS backup by intercept is available when needed.²⁵ To qualify as an ALS unit, at least one member of the team must possess training beyond the EMT level. Most commonly, ALS units now are staffed by at least one paramedic, although many ALS services utilize units staffed by two paramedics. Additional equipment and supplies must be available on the ALS unit to support the defined scope of practice.

Rotor-Wing Aircraft

Helicopter evacuation of military casualties began during World War II, expanded in the Korean War and matured during the Vietnam War.²⁹ The improvement noted in survival was largely attributed to the speed of evacuation to facilities capable of providing initial trauma care. Civilian air medical services were established in the United States as a result of the success during wartime and have proliferated throughout the industrialized world.

In the United States, helicopter EMS (HEMS) programs are most commonly operated by a private EMS service or are hospital based; however, the Coast Guard, military, law enforcement agencies, or park services may also provide helicopter transport. Crew configurations vary from service to service. The two most common combinations are two flight nurses or a flight nurse and a paramedic. Helicopters are equipped as ALS units and often function as compact intensive care units. HEMS personnel generally have an expanded scope of practice compared to ground EMS providers, including a greater variety of medications and additional skills (eg, management of an intra-aortic balloon pump, ECMO, complex ventilators, tube thoracostomies, RSI, etc), but only a small portion may be applicable to the care of trauma patients. Many advanced HEMS services are now carrying packed red blood cells and plasma to use with patients who have uncontrolled hemorrhage. The usual transport radius for a helicopter is 150 miles, depending on the helicopter model.

Helicopter transport appears to be beneficial for wilderness rescue and for the transport of critically injured patients from a rural facility with limited resources to a major trauma center.^30,31 Analysis in a study from the CDC of nearly 55,000 HEMS transported patients enrolled in the National Trauma Data Bank (NTDB) showed that the odds of death were 39% lower in patients transported by air versus ground.³² An even larger study based on data from the NTDB of 256,387 patients showed that, even though HEMS transported patients had more severe injuries, they had lower mortality and were more likely to be discharged home.³³ A study from Nova Scotia, where HEMS and ground transport were under the same dispatch center and had the same medical oversight and the same destination medical facilities, showed that the transport of blunt trauma patients with ISS of greater than 12 by air showed significantly better outcomes than those transported by ground ambulance.³⁴ Loss of HEMS in one rural area was shown in one study to decrease interfacility transfers, increase transfer times and led to a fourfold increase in mortality of transferred patients.³⁵ A similar study in a different region of the United States showed no difference in transport times or mortality after loss of HEMS transport capability.³⁶ The introduction of a second helicopter to the Eastern end of Long Island significantly reduced trauma mortality.³⁷ Unfortunately, many trauma patients transported by HEMS are not critical and, in many trauma centers, it is not unusual for up to one-third of the patients transported by HEMS to be discharged from the emergency department. It is essential that HEMS transports have strong utilization review and medical oversight. HEMS programs need to be fully integrated into the EMS and trauma systems to minimize patient discharge from the emergency department.

The benefits of on-scene HEMS response are also debatable in an urban or suburban setting when a well-trained ground EMS service is present and transport times are brief.^38,39 This is a systems’ issue since extenuating circumstances such as severe traffic congestion or a mass casualty incident may change HEMS utility in urban areas. A recent study by Diaz et al⁴⁰ found that ground transport is always faster than air medical transport when the distance from the scene to the trauma center is 10 miles or less, while helicopter transport is always faster when the scene is more than 45 miles from the trauma center. These findings are not surprising considering the time it takes to power up and power down a helicopter. Many EMS systems have the PSAP autolaunch the helicopter based on preset criteria to accelerate dispatch. This is especially true with scenes with potential serious injuries based on information obtained from callers into 911. The helicopter may launch and even land to assess the situation. The helicopter may not necessarily transport the patient and no charge to the patient is made in that event.

There is a noteworthy element of risk associated with air medical transport, and a study by Bledsoe and Smith⁴¹ documented a steady and marked increase in the number of crashes of medical helicopters over the decade of 1993–2002. This trend has continued at an alarming rate since that study was published, resulting in significant loss of life of both patients and the air medical crews. This serious problem is in the process of mitigation since HEMS safety hearings were held by the National Transportation Safety Board (NTSB) in 2009 involving all of the HEMS interested parties. Recommendations were made by the NTSB to the FAA regarding rulemaking pertaining to HEMS safety. The initial draft rules were published in 2014 and finalized in 2015⁴² and include such safety items as radar altimeters, helicopter terrain and avoidance warning systems (HTAWS), requires the pilot in command (PIC) to maintain current instrument flight rating status and require flight data monitoring systems on HEMS aircraft. All HEMS flights will be flown under the more stringent parameters of FAA Part 135. The various aspects of these rules will be phased in over several years. In addition, over 90% of programs have instituted night vision goggle usage. There has been a marked increase in simulator training by HEMS programs, also. The FAA has been mandated to collect data on HEMS flights to determine if these measures increase HEMS safety or if additional measures are needed in rules such as mandating night vision goggles, actual flight data recorders, mandated simulator training for all HEMS pilots or autopilots for all HEMS aircraft. A recent study from the United Kingdom analyzed all HEMS accidents over the past 26 years and compared their numbers to those of Australia, Germany, and the United States. The authors considered the accident rates per 10,000 missions and the fatal accident rates per 10,000 missions to be comparable.⁴³ A position paper/policy statement (Appropriate and Safe Utilization of Helicopter Emergency Medical Services)⁴⁴ was jointly developed by several organizations involved with HEMS along with a background paper.⁴⁵ Another joint paper by ACS-COT and NAEMSP on HEMS guidelines for appropriateness and safety has also been published.⁴⁶

Fixed-Wing Aircraft

Fixed-wing aircraft are constrained by the need for a runway and, therefore, lack the versatility of rotor-wing units that can land at an accident scene or at a trauma center. With the additional time required to transport a patient to and from a local airport, fixed-wing aircraft only become more time-efficient when a patient requires transfer over a distance greater than about 150 miles. Aircraft equipped for air medical transport often serve to transfer patients to regional specialized facilities such as those for burns or spinal cord injuries or to transplant centers. The equipment and supply requirements for fixed-wing aircraft are not as well defined as for ground or rotor-wing units.

Quality medical care is a vital issue in all areas of the health care system. This is attained by developing a performance improvement (PI) process. PI is an ongoing cycle of evaluation, data collection, interpretation, and modification of the system to improve patient care.⁴⁷

An EMS service should have its own internal PI program, with strong oversight by the medical director of the service. Key aspects of this program include evaluation of the care rendered and monitoring the efficiency of the EMS system. A variety of methods are utilized in order to determine if care is rendered in a timely, efficient, and medically sound fashion. Equipment must be reliable and durable in order to withstand the sometimes austere and difficult conditions associated with the delivery of prehospital care and not contribute to injury. Trauma centers should also evaluate the care of the patients transported to their facilities and provide appropriate feedback to EMS system administrators, medical directors, and field personnel.

System Efficiency

The evaluation process for any EMS system must determine the efficiency of all components involved in providing care to the patient. One method of evaluating efficiency of the system is to review notification time, response time, on-scene time, and transport time.

Notification time

This represents the time interval between the injury and notification of the EMS dispatch center. In the United States, most requests for EMS arrive via the 911 phone system. By 2015, 96% of the US population lived in an area covered by enhanced 911 (E911), although that only represents about 50% of the counties in the country.⁴⁸ E911 is capable of delivering a wireless caller’s number and location to the appropriate PSAP. The PSAP may still have to pass information along to the EMS dispatch center.

Response time

This is defined as the period that starts when an emergency call is received by the EMS dispatch center and ends with the arrival of the ambulance at the patient’s side. This time frame encompasses several actions as follows: (a) the call must be physically received; (b) the dispatcher must analyze the call and decide on the appropriate response; (c) the ambulance must be contacted and dispatched; and (d) the ambulance must leave its current location and travel to the scene. The final factor, ambulance travel time, is a function of location and availability of the ambulance, weather, and traffic conditions.

The desired response time for any system directly impacts the number of ambulances that the system requires. In order to meet the target response times, sufficient EMS units must be available to meet the expected number of emergency calls in the coverage area. While many urban systems have set a response time standard of 8 minutes that must be met 90% of the time, the ideal response time for trauma is unknown. A retrospective study failed to identify an association between shorter EMS response times and improved outcome in trauma patients.⁴⁹

On-scene time (scene time)

This is the interval from the arrival of EMS at the scene until their departure en route to the receiving facility. This time will vary according to environmental conditions, geography of the scene and location, accessibility of the patient, entrapment, injuries present, and requirements for packaging of the patient. When caring for a critically injured patient, the EMS personnel should strive to limit their on-scene time to 10 minutes or less.⁵⁰ Approximately 85–90% of trauma patients encountered by EMS are not critically injured and, thus, do not require rapid packaging and immediate transport. Continuous monitoring of on-scene times should be performed to ensure that time is not being lost in the performance of unnecessary procedures on patients with severe injuries.

Transport time

This is the length of time required to transport the patient from the scene to an appropriate facility. The factors that affect this time are distance from the facility, weather, transport modality (air vs ground), and traffic conditions, if transported via ground. The choice of a destination facility is an important decision in the care of the critical patient. The local or regional EMS system in conjunction with the trauma system must have criteria in place for appropriate transport to the appropriate facility.⁵¹ A patient who requires emergent operative intervention to control hemorrhage should be taken to a hospital staffed and equipped to move the patient to the operating room immediately, if such a facility is available. PI reviews should address these issues in an ongoing manner.

Care Rendered

The medical director and leadership of an EMS service must be able to objectively review the care rendered by the personnel they supervise. Evaluation of medical care can be separated into prospective, concurrent, and retrospective phases.

Prospective evaluation

This form of evaluation attempts to improve the level of care rendered prior to the actual delivery of the care. Evaluating continuing education programs and periodic assessment of skills are examples of prospective evaluation tools.

Concurrent evaluation

Concurrent evaluation involves direct observation of the EMS personnel during the delivery of care. The medical director or a designated member of the staff of the EMS system (eg, field training officer) accompanies the crew in order to observe the delivery of care in the field. Trauma surgeons may also evaluate the EMS personnel’s assessment and care as they deliver patients to their facility. Steps can be taken immediately to correct deficiencies and improve patient care.

Retrospective evaluation

Retrospective evaluation occurs after care has been delivered. This form of review is the easiest and least costly of the methods and comprises chart audits, case reviews, and debriefings to review the events of any particular EMS call. Trauma surgeons should participate in the retrospective evaluation of EMS services that transport patients to their facility. Such involvement helps EMS providers gain perspective into the entire spectrum of trauma care. A noninclusive list of audit filters that may be utilized to evaluate prehospital care are shown in Table 7-2. Customized audit filters for specific local/regional PI initiatives should be incorporated as the PI process matures.