Jeffrey P. Salomone and Joseph A. Salomone III
Critically injured patients must receive high-quality care from the earliest postinjury 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 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 1962.1 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 1960s, 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,7–9 while others showed that paramedics could employ ALS measures in an expeditious manner.10–13
EMERGENCY MEDICAL SERVICES SYSTEM
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
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 assure 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.
TABLE 7-1 EMS Provider Levels
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.” 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 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 in 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 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 AEMT replaces both the 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 beta-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, 45 states utilize the NREMT examination process. While current exams are based on the National Standard Curricula, NREMT will phase in new exams based on the National EMS Scope of Practice Model between 2011 and 2013.
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. While some states require that all paramedic training programs be approved by CoAEMSP, many states have no such requirements. In fact, EMS (i.e., paramedic) is the only allied health profession that does not require graduation from an accredited program in order to work in the field. One recent study demonstrated that graduates of accredited paramedic programs are more likely to successfully achieve certification by the NREMTs.21 For these reasons, the NREMT will require applicants for the paramedic certification exam to have graduated from an accredited education program after January 1, 2013.
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. This includes 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 (e.g., 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. In this context, nurses are limited in their roles just as in ground transport. They provide important knowledge and skills in critical care, but need to be paired with a partner who is licensed to perform in the prehospital arena in most states. Nurses who are dual trained as both an EMT and a nurse can provide care in the prehospital phase as dictated by their EMS certification and license.
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 some air medical services utilize physicians as members of their 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 and 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.
Prior to the early 1970s, EMS 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, that is, basic life support (BLS) and ALS.22
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 automatic or 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 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 (e.g., 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.
Equipment for EMS Units
The American College of Surgeons Committee on Trauma (ACSCOT) joined with the American College of Emergency Physicians (ACEP), the National Association of EMS Physicians, and other organizations to publish a document delineating the necessary equipment that should be stocked on an EMS unit.24 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 (i.e., 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.
EMS units operating on the ground may possess transport capabilities (i.e., 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 is available when needed.22
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.
Helicopter evacuation of military casualties began during the Korean War and matured during the Vietnam War.25 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 (e.g., management of an intra-aortic balloon pump, etc.), but only a small portion may be applicable to the care of trauma patients. The typical maximum transport radius for a helicopter is 150 miles.
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.26–30 When outcome for trauma patients transported by HEMS has been studied, conflicting results have been found. While some studies have correlated an improvement in the outcome of victims of blunt trauma transported by helicopter,31–34 other studies have found little or no benefit.26,35,36 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.
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.37,38 A recent study by Diaz et al.39found 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.
There is a noteworthy element of risk associated with air medical transport, and a study by Bledsoe and Smith40 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. For all these reasons, increasing controversy surrounds the utility of HEMS for transportation of injured patients in the civilian setting.
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 small performance improvement (PI) process. PI is an ongoing cycle of evaluation, data collection, interpretation, and modification of the system to improve patient care.41
An EMS service should have its own internal PI program, with oversight by the service medical director. 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 harsh 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.
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 2006, 75% 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.42 Many rural and frontier areas still lack this coverage. E911 is capable of delivering a wireless caller’s number and location to the appropriate Public Safety Answering Point (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 scene. 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.43
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.44 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 by ground. The choice of a destination facility is an important decision in the care of the critical patient. 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.
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 (e.g., 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. Examples of audit filters that may be utilized to evaluate prehospital care are shown in Table 7-2.
TABLE 7-2 Audit Filters for Prehospital Trauma Care
One of the most important relationships in EMS is that between the prehospital providers and the physician. In the United States, EMS personnel practicing at the ALS level can be thought of as physician extenders.45 While State EMS offices issue licenses to prehospital care providers, they are not allowed to function independently and function under the auspices of their medical director. Thus, EMS personnel perform under delegated practice, which is typically described in the Medical Practice Act in state law.
Numerous terms have been applied to the association between EMS providers and the supervising or responsible physicians, including medical control, medical direction, and medical oversight. Medical direction of an EMS system is provided in a variety of fashions that differ from region to region. In some systems a single physician provides medical direction, and, in other circumstances, medical direction is carried out by a group of physicians acting collectively through a consensus process.
In 1986, Holroyd et al.46 recommended that the EMS medical director be a physician with the following qualifications: (a) knowledge and demonstrated ability in planning and operation of prehospital EMS systems; (b) experience in the prehospital provision of emergency care for acutely ill or injured patients; (c) experience in the training and ongoing evaluation of all levels of participants in the prehospital care system; (d) knowledge and experience in the application of medical control to an EMS system; and (e) a knowledge of the administrative and legislative processes affecting regional and/or state prehospital EMS systems.
The medical director must be interested in and committed to the day-to-day activities of the EMS service. The role of medical director for an EMS service is not limited to emergency physicians, and trauma/critical care surgeons are well suited to function in this role once they have gained the prerequisite knowledge of how EMS systems function. The National Association of EMS Physicians has developed a workshop for EMS medical directors.
Medical control is divided into two categories including indirect (off-line/protocols) and direct (on-line).47
This form of medical direction involves the development of written protocols and the review of EMT performance. The amount of time required to accomplish these administrative duties varies with the size and complexity of the particular EMS system. The medical director’s review of care is a PI function and has been discussed previously.
Protocols are the overall steps in patient management that are to be followed by the prehospital provider at every patient contact. As an accurate diagnosis is often not possible in the field, protocols are usually developed based on the patient’s complaints or condition. For ease of memorization and integration with those of other conditions, many protocols are designed in an algorithmic fashion. Trauma surgeons should participate in the development of EMS protocols regarding care for injured patients in their region.
Direct or on-line medical control by the medical director is clinical in nature.48 This form of direction involves providing radio or telephone instructions to prehospital providers for conditions that are not covered in their protocols and direct observation of individual performance.
Early in the development of EMS systems, a great deal of emphasis was given to direct medical control. Many authorities believed that direct communication between the physician and the prehospital providers would be the mainstay of good prehospital care. Despite this, several studies have demonstrated that there is no difference in survival with and without on-line medical control and less time is spent in the field when there is no requirement to call the hospital.49
TRAUMA EDUCATION FOR EMS PERSONNEL
Two continuing education courses have been developed to provide EMS personnel with the essential knowledge and skills to manage critically injured patients. Both courses have been promulgated nationally and internationally.
Prehospital Trauma Life Support
The Prehospital Trauma Life Support (PHTLS) program was developed by the National Association of EMTs in cooperation with the ACSCOT.44 The PHTLS course is based on the tenets of the Advanced Trauma Life Support course developed by ACSCOT, but has been modified to meet the needs of the patient in the prehospital setting.50 The central philosophy of the PHTLS course is that EMS providers, when given an appropriate fund of knowledge, can make appropriate decisions regarding patient care. Thus, the course emphasizes “principles” of management, rather than focusing on individual preferences or protocols.
A new edition of the course is produced every 4 years, 1 year after the revised ATLS course has been released. This strategy guarantees that PHTLS continues to disseminate any changes in treatment or philosophy that have been introduced in ATLS and ensures a seamless interface between the prehospital providers and personnel in the emergency department in the initial management of the trauma patient. PHTLS is currently taught throughout the United States and in almost 50 foreign countries.
International Trauma Life Support
About the same time that PHTLS was developed by NAEMT, the Alabama Chapter of the ACEP developed the Basic Trauma Life Support course.51 The course was subsequently transitioned to BTLS International, a not-for-profit organization, and, in 2005, the name was changed to International Trauma Life Support (ITLS). Like PHTLS, ITLS is also based on the philosophies of ATLS and taught both in the United States and internationally.
ASSESSMENT AND MANAGEMENT
Assessment and management of the injured patient in the prehospital setting should proceed in an orderly manner, despite the fact that the EMT must frequently make rapid decisions about patient care under adverse conditions. While the general approach is based on that taught in the ATLS course, one important modification is that the EMT first performs a “scene assessment” prior to evaluating an individual patient. Next, a “primary survey” is conducted to identify life-threatening conditions and initiate immediate therapy.
At the end of the primary survey the EMT considers whether life-threatening or potentially life-threatening injuries have been identified. If so, the patient is expeditiously packaged and transported to the closest appropriate facility. Definitive care for severe, uncontrolled internal hemorrhage cannot be provided in the field, and surgery is usually required. Interventions such as direct pressure on a bleeding wound and infusion of intravenous fluids are not substitutes for rapid transportation to an appropriate facility with immediate surgical capabilities.
Assessment of the Scene
In the prehospital setting, assessment of the patient actually begins before reaching the patient’s side. As an EMS crew is dispatched to a scene, they begin to consider numerous factors that may play a role in caring for the patient, as well as ensuring their safety and that of the patient. These factors include such things as mechanism of injury, environmental conditions, and hazards present at the scene. The important aspects of this assessment can be divided into the following two key categories: safety/standard precaution and situation.
Prehospital personnel must first evaluate the safety of the scene. EMS must not enter into a situation that puts their health and well-being at risk as this puts them in jeopardy of becoming patients as well. EMS workers are dependent on law enforcement personnel to ensure that the scene has been cleared of violent assailants and their weapons. In addition to their personal safety, the EMS providers need to consider concerns that threaten the safety of the patient. The scene of a traumatic incident may include dangers such as traffic, downed power lines, hazardous materials, and harsh environmental conditions. In light of incidents of terrorism there is heightened concern of chemical, biological, or nuclear contamination of a scene, or secondary devices planted with the intent of killing rescuers.
Standard Precautions. One hazard ubiquitous to virtually all trauma scenes is blood. Blood and other body fluids may contain communicable diseases including hepatitis and human immunodeficiency viruses. In any patient encounter, health care workers are encouraged to employ measures to decrease the risk of contracting these pathogens. Standard precautions involve the use of impermeable gloves, gowns, masks, and goggles. In addition to wearing this protective gear, EMS providers must also exercise caution when handling sharp devices, such as needles that are contaminated with a patient’s blood or body fluid.
The second component of the scene assessment is evaluation of the situation. The EMS providers should consider the following issues: the number of patients and their ages; the need for specialized personnel or equipment (power company, heavy rescue); the need for additional EMS units, including summoning an air medical helicopter; the need for a physician at the scene to assist with triage; and the possibility that the traumatic event was triggered by a medical emergency (acute myocardial infarction or a cerebrovascular accident). Because the EMS personnel are essentially the “eyes and ears” of the emergency physician and trauma surgeon at the scene, they are in the position to observe key data about the mechanism of injury.
Kinematics. An understanding of the mechanism of injury assists in evaluating the patient for potential injuries (see Chapter 1). Certain mechanisms frequently result in specific injury patterns. Recognition of the mechanism may guide providers in the assessment of the patient. If the incident involves a motor vehicle crash, the EMS crew should evaluate the type of collision (frontal, rear, or lateral impact, etc.) and note the degree of damage to the vehicles. The location of the patient at the time of the crash and the use of restraints or protective gear is also valuable information. For penetrating trauma, the caliber of the weapon and distance from the assailant should be documented.
After assessing the scene, EMS personnel perform a primary survey of the patient (see Chapter 10). As taught in ATLS, this survey serves to identify life-threatening or potentially life-threatening conditions. While it is taught in a stepwise A–B–C–D–E approach, one must remember that many aspects of this evaluation can be done simultaneously. EMS personnel employ a “treat as you go” philosophy, wherein care is initiated for life-threatening conditions as they are identified. Thus, the primary survey establishes a framework for setting priorities for management.
Management of the airway is given highest priority, but care must be taken not to aggravate a potential injury to the cervical spine (see Chapter 11). One EMS provider applies manual in-line stabilization to the head and neck while a coworker begins assessment and management of the airway. This stabilization of the cervical spine is continued either until the patient is completely immobilized on a long backboard or until it is determined that the patient does not require spinal immobilization.
All EMS providers, regardless of their level of training, must master the “essential skills” of airway management.44 These skills include the following: manually clearing the patient’s airway of foreign material, manually opening the airway using the trauma jaw thrust or trauma chin lift, suctioning the oropharynx, and inserting basic oral or nasal airways. An algorithm for prehospital management of the airway is provided (Fig. 7-1).44
FIGURE 7-1 Airway management. (Reproduced with permission from Salomone JP, Pons PT, McSwain NE, eds. PHTLS: Prehospital Trauma Life Support. 7th ed. St. Louis: Mosby; 2011:140. Copyright © Elsevier.)
Endotracheal Intubation. While this has long been the “gold standard” for securing an airway in the hospital, its role in prehospital care has become increasingly controversial. This skill is typically limited to advanced providers, though all levels of EMTs have now been taught to safely insert endotracheal tubes. The use of this technique is almost universally accepted at the EMT-Paramedic level throughout the United States. A limited number of communities have allowed EMT-Bs to be trained in endotracheal intubation. In most EMS systems, the success rate for endotracheal intubation exceeds 90%. With good, indirect medical control and field preceptors, training in endotracheal intubation can be successfully accomplished.52
Because of the concern of potential fractures of the cervical spine, endotracheal intubation should be performed concurrently with in-line stabilization of the cervical spine.53,54 While intubation is most commonly accomplished via the orotracheal route using a laryngoscope, other techniques include blind nasotracheal intubation, digital intubation, and retrograde intubation, although these are rarely utilized in the field.55–57
Indications for endotracheal intubation in the field include the following:
• Inability of patient to maintain an airway due to altered level of consciousness (Glasgow Coma Scale [GCS] score <8)
• Need for assisted ventilations
• Threatened airway (e.g., respiratory burns, expanding hematoma of the neck)
Concern has arisen that endotracheal tubes placed in the prehospital setting may be misplaced or may become dislodged more commonly than previously believed.58 Once endotracheal intubation has been performed, care should be taken to confirm proper placement using a combination of clinical assessments and adjunctive devices. The clinical assessments include presence of bilateral breath sounds and the absence of ventilatory sounds over the epigastrium, chest rise with ventilation, fogging of the endotracheal tube, and the provider watching the tube pass through the vocal cords. Adjuncts that help confirm a successful intubation include colorimetric CO2 detectors, capnography, and the esophageal detector device.59 Following intubation, the tube is carefully secured and its position checked each time the patient is moved. A recent publication suggests that continuous capnography in the prehospital setting may significantly reduce the incidence of misplaced or dislodged ET tubes.60
A number of EMS services, especially air medical programs, permit their providers to perform rapid sequence intubation (RSI). This involves the administration of both a sedating agent and a neuromuscular blocking agent prior to endotracheal intubation. In skilled hands, this technique can facilitate effective airway control in patients when other methods fail or are otherwise unacceptable (e.g., the patient with trismus). The role of RSI in the prehospital setting is controversial, primarily because of both concerns related to the risks of losing a partially patent airway by administration of a paralytic agent and data suggesting that patient outcomes may be compromised when RSI is performed by EMS personnel.
With adequate medical control, several studies have documented that EMS personnel can safely perform this procedure.61–63 Data from one case–control study, however, demonstrated an interesting paradox. While paramedics using RSI had a higher success rate at performing endotracheal intubation, the patients with suspected severe traumatic brain injury (TBI) intubated with RSI had a higher mortality than did those in the control group.64 Davis et al.65recently published the findings of an expert panel on the role of prehospital RSI.
Wang and Yealy66 reviewed the data on prehospital intubation and concluded that there is little literature to support maintaining endotracheal intubation as the standard airway of choice. More studies have documented worsened outcomes than improved outcomes. If intubation is utilized, the EMS systems must carefully review each intubation attempt and ensure that it is being performed safely.
Supraglottic Airways Percutaneous Transtracheal Ventilation (PTV). These are devices that are inserted without a laryngoscope (i.e., blindly) into the hypopharynx. Although various models differ in design, properly positioned devices have openings that allow for passage of air from the device into the adjacent glottic opening to ventilate the lungs. Some devices have two ports and ventilations are then administered through the port that results in chest excursion and breath sounds (pharyngotracheal lumen (PtL) airway, Gettig Pharmaceutical Instrument Company, Spring Hills, PA; Combitube, Nell-cor, Typo Healthcare, Pleasanton, CA). A newer but similar alternative has a single ventilation port making it even easier to use (King LT airway, King Systems, Noblesville, IN).
Another supraglottic device is the laryngeal mask airway (LMA) (LMA North America, San Diego, CA), consisting of an inflatable silicone ring attached to a silicone tube. This device is blindly inserted into the hypopharynx so that the ring seals around the glottic opening. Ventilation is then provided through the tube. This device has replaced endotracheal intubation for general anesthesia in a significant percentage of shorter operations, especially in Great Britain. LMAs have been popular in the prehospital setting in Europe and with some air medical services in the United States.67
The primary advantage of supraglottic airways is that minimal training is necessary to achieve competency because of their design and the blind insertion. A potential disadvantage of these devices is that the risk of aspiration is believed to be greater than with endotracheal intubation. Supraglottic devices are valuable backup (“rescue”) airways when endotracheal intubation cannot be accomplished. Because of the controversies with endotracheal intubation, these airways are increasingly utilized as the initial airway of choice. This is especially true in the urban setting where transport times are generally brief.
This involves the insertion of a large-bore needle through the cricothyroid membrane and connecting it to high-pressure oxygen. The lungs are then insufflated periodically. This technique possesses the following advantages: it does not require paralysis, is less invasive than surgical cricothyroidotomy, affords easy access and insertion, and requires minimal education and very basic equipment. The technique has been demonstrated experimentally to be safe and effective even in the presence of complete obstruction of the airway. While oxygenation is adequate, studies have shown that the patient may become hypercarbic.68 PTV is indicated when an injured patient is unable to be intubated and cannot be ventilated using a BVM device and an alternative airway.
Surgical Cricothyroidotomy. This involves incising the skin and the cricothyroid membrane, followed by the insertion of a small endotracheal or tracheostomy tube. Because it is highly invasive, complications have included significant hemorrhage and injury to adjacent nerves, blood vessels, and the larynx. Air medical crews have utilized surgical cricothyroidotomy in the prehospital setting for several decades.69
Groups from Indianapolis and Tucson have reported on their experiences with this procedure when performed by ground ambulance crews.70,71 Although these authors concluded that surgical cricothyroidotomy could be safely performed by paramedics assigned to ground units, many experts have argued that the procedure was excessively utilized. In the studies, between 10% and 20% of the total field airways were surgical, and, of these, 20–25% were performed as the initial technique of airway management. Well-trained air medical crews who have been allowed to perform this skill have demonstrated a much smaller need. In systems with tight medical control, EMS providers could consider this procedure when faced with the “can’t intubate, can’t ventilate” situation.
The patient’s ventilatory status (“breathing”) is next examined. If the patient’s ventilatory rate is 10 or less, ventilations should be assisted with a BVM device connected to 100% oxygen. The tidal volume should be estimated if the patient is tachypneic. Rapid, shallow breaths indicate inadequate minute ventilation and require assistance with a BVM. Auscultation of breath sounds should be performed during the primary survey if the patient has an abnormal ventilatory rate or evidence of respiratory distress. Most patients who have suffered an injury benefit from supplemental oxygen. Pulse oximetry should be monitored, and oxygen administered to maintain an SpO2 ≥95%.
Prehospital care providers must exercise caution while providing ventilatory support, as deleterious effects may ensue. Hyperventilation by EMS personnel in one study was associated with increased mortality in patients with suspected TBI.72 Additionally, data from animal models suggest that hyperventilation resulted in auto-positive end-expiratory pressure (PEEP) that further compromised the hemodynamic status of a hypovolemic swine.73 For an adult patient, a reasonable tidal volume of 350–500 mL delivered at a rate of 10 breaths/min is probably sufficient to maintain a satisfactory oxygen saturation while minimizing the risk of hyperventilation. Continuous pulse oximetry and capnography can help guide the ventilatory support.
Assessment of a patient’s circulatory status involves examining for external hemorrhage and evaluating the adequacy of perfusion. Most life-threatening external hemorrhage can be controlled with direct pressure. If man power is limited, a pressure dressing with gauze pads and an elastic bandage can be placed around an extremity. Should direct pressure alone not control bleeding in an extremity, a tourniquet should be applied just proximal to the site of hemorrhage and tightened until bleeding ceases. No published data document any significant decrease in hemorrhage when a bleeding extremity is elevated, and such manipulation may result in the conversion of a closed fracture to an open one. The efficacy of applying pressure over “pressure points” in the axilla and groin has also not been studied in the prehospital setting and is labor intensive. In the operating room, arterial tourniquets have been used safely for periods of 120–150 minutes. Options for a tourniquet include a blood pressure cuff, a cravat tied into a “Spanish windlass,” and the use of a manufactured tourniquet.74 If a manufactured tourniquet is used, it should be one that has been tested and recommended by the Committee on Tactical Combat Casualty Care (CoTCCC).75
A sample protocol for application of a tourniquet is described as follows and is shown in Fig. 7-2.
FIGURE 7-2 Protocol for tourniquet application. (Reproduced with permission from Salomone JP, Pons PT, McSwain NE, eds. PHTLS: Prehospital Trauma Life Support. 7th ed. St. Louis: Mosby; 2011:201. Copyright © Elsevier.)
Kragh et al.76,77 studied the outcomes of casualties who had tourniquets applied for their extremity wounds. Their data demonstrated that prehospital use of tourniquets was lifesaving and that complications were low. Less than 2% of the patients suffered transient nerve palsy at the level where the tourniquet was applied, and no limbs were sacrificed because of tourniquet use. In patients who had a tourniquet on for 2 hours or less, 28% required fasciotomy, while a slightly higher percentage (36%) required fasciotomy if the tourniquet was in place longer than 2 hours.
A topical hemostatic agent should be considered for significant external hemorrhage from body areas not amenable to placement of a tourniquet (neck, torso, axilla, and groin). In laboratory and clinical studies the military has found several of these agents to be effective, including those incorporating chitosan, zeolite (a derivative of volcanic rock), or kaolin clay.78,79 Zeolite been associated with thermal injury as a result of an exothermic reaction that takes place when the material comes in contact with water.80 The CoTCCC currently recommends Combat Gauze that is impregnated with kaolin clay as the topical hemostatic agent of choice.75
Perfusion is assessed primarily by evaluating pulse rate and quality, skin color, temperature, and moisture; however, prolonged capillary refill time may add further evidence that the patient is in shock. Time should not be taken in the primary survey to measure blood pressure. Even mild tachycardia (heart rate >100/min) should always make one consider that the injured patient is hypovolemic. Significant tachycardia (>120/min), weak peripheral pulses, and anxiety are associated with loss of 30–40% of the blood volume of an adult.50
Traumatic Cardiopulmonary Arrest. Trauma patients who are found in cardiopulmonary arrest require special consideration. Unlike cardiopulmonary arrest associated with an acute myocardial infarction, most patients who suffer cessation of their vital signs prior to the arrival of EMS have exsanguinated. CPR, defibrillation, antidysrhythmic medications, and crystalloid resuscitation will not reverse this. Attempts at resuscitation are typically futile and place the EMS personnel at unnecessary risk from automobile crashes during emergency transport and exposure to blood. The National Association of EMS Physicians and the ACSCOT have collaborated on a position paper that endorses the following guidelines81:
• For victims of blunt trauma, resuscitation efforts may be withheld if the patient is pulseless and apneic on the arrival of EMS.
• For victims of penetrating trauma, resuscitation efforts may be withheld if there are no signs of life (papillary reflexes, spontaneous movement, or organized cardiac rhythm on the electrocardiogram greater than 40/min).
• Resuscitation efforts are not indicated when the patient has sustained an obviously fatal injury (such as decapitation) or when evidence exists of dependent lividity, rigor mortis, and decomposition.
• Termination of resuscitation should be considered in trauma patients with an EMS-witnessed cardiopulmonary arrest and 15 minutes of unsuccessful resuscitation including CPR.
• Termination of resuscitation should be considered for a patient with traumatic cardiopulmonary arrest who would require transport of greater than 15 minutes to reach an emergency department or trauma center.
• Victims of drowning, lightning strike, or hypothermia, or those in whom the mechanism of injury does not correlate with the clinical situation (suggesting a nontraumatic cause) deserve special consideration before a decision is made to withhold or terminate resuscitation.
During the primary survey, the EMS provider assesses neurologic function by evaluating the patient’s GCS score and pupillary response. The GCS score comprises three components including eyes, verbal, and motor.82 If a painful stimulus is required to complete the assessment, the EMT can either apply pressure to the nail bed or squeeze the axillary tissue. If the patient has an altered level of consciousness (GCS <15), pupillary response to light is assessed. Any belligerent, combative, or uncooperative patient should be considered to be hypoxic or have a TBI until proven otherwise. In a trauma patient, a GCS score of ≤13, seizure activity, or a motor or sensory deficit are all reasons for concern.
Exposure and Environmental Control
The final part of the primary survey involves a quick scan of the patient’s body to note any other potentially life-threatening injuries. In general, this requires removal of the patient’s clothes, but environmental conditions and the presence of bystanders may make this impractical. Hypothermia from failure to preserve body heat can contribute to a serious coagulopathy in the trauma patient.
Heavy, dark colored woolen clothing may absorb significant amounts of blood. On occasion, patients may have more than one mechanism of injury, that is, blunt trauma from a motor vehicle crash that occurred while trying to flee the assailant who had shot them. Injuries cannot be treated unless they are identified.
On completion of the primary survey, the EMS provider determines whether or not the patient is critical (Fig. 7-3). Because the primary survey involves a “treat as you go” philosophy, airway management, ventilatory support, and control of external hemorrhage are initiated as the problems are identified.
FIGURE 7-3 Prehospital care overview. (Reproduced with permission from Salomone JP, Pons PT, McSwain NE, eds. PHTLS: Prehospital Trauma Life Support. 7th ed. St. Louis: Mosby; 2011:429. Copyright © Elsevier.)
When a critically injured patient is identified (Table 7-3), scene time should ideally be less than 10 minutes, unless extenuating circumstances, such as extrapment or an unsafe scene, preclude this. A retrospective study of the outcome of seriously injured trauma patients (Injury Severity Score >15) in an urban setting demonstrated improved survival when the patient was transported by private vehicle compared to an ALS unit, primarily because the EMS crews were spending, on average, more than 20 minutes on scene.83
TABLE 7-3 Critical Trauma Patient
If indicated, spinal immobilization should be performed expeditiously and the patient moved to the ambulance. Time is not taken to splint each individual fracture. For the critically injured patient, immobilization to the long backboard provides satisfactory immobilization of potential musculoskeletal injuries.
Because definitive care cannot be provided to the critically injured patient in the field, EMS personnel must realize that initiation of transport to the closest appropriate facility demonstrates good judgment. Originally developed by the ACSCOT, the Field Triage Decision Scheme was recently revised by a national expert panel convened by the Centers for Disease Control and Prevention (CDC) (Fig. 7-4).84 The revision has been endorsed by more than 35 national organizations with EMS or trauma care. According to this algorithm, patients who meet specific anatomic or physiologic criteria should be transported to the highest level of care in the system, typically a Level I or II trauma center. Patients who meet mechanism of injury criteria should be transported to the closest trauma center, which need not be a Level I or II. Protocols should be written so that EMS personnel may bypass a closer hospital in order to take a patient with life-threatening injuries to a trauma center.
FIGURE 7-4 Field Triage Decision Scheme. Abbreviation: EMS, emergency medical services. (Reproduced from Sasser SM, Hunt RC, Sullivent EE, et al. Guidelines for field triage of injured patients: recommendations of the national expert panel on field triage. MMWR. 2009;58:1.)
*The upper limit of respiratory rate in infants is >29 breaths per minute to maintain a higher level of overtriage for infants.
†Trauma centers are designated Level I-IV. A Level I center has the greatest amount of resources and personnel for care of the injured patient and provides regional leadership in education, research, and prevention programs. A Level II facility offers similar resources to a Level I facility, possibly differing only in continuous availability of certain subspecialties or sufficient prevention, education, and research activities for Level I designation; Level II facilities are not required to be resident or fellow education centers. A Level III center is capable of assessment, resuscitation, and emergency surgery, with severely injured patients being transferred to a Level I or II facility. A Level IV trauma center is capable of providing 24-hour physician coverage, resuscitation, and stabilization to injured patients before transfer to a facility that provides a higher level of trauma care.
§Any injury noted in Step Two or mechanism identified in Step Three triggers a “yes” response.
**Intrusion refers to interior compartment intrusion, as opposed to deformation which refers to exterior damage.
††Includes pedestrians or bicyclists thrown or run over by a motor vehicle or those with estimated impact >20 mph with a motor vehicle.
§§Local or regional protocols should be used to determine the most appropriate level of trauma center within the defined trauma system; need not be the highest-level trauma center.
***Patients with both burns and concomitant trauma for whom the burn injury poses the greatest risk for morbidity and mortality should be transferred to a burn center. If the nonburn trauma presents a greater immediate risk, the patient may be stabilized in a trauma center and then transferred to a burn center.
Infusions of crystalloid solutions and blood transfusion are the mainstays of therapy for the in-hospital treatment of severe hypovolemic shock (see Chapter 12). Because it requires refrigeration and typing, blood is not available in the prehospital environment. Isotonic crystalloid solutions, such as lactated Ringer’s or normal saline (0.9% sodium chloride), can be used for volume resuscitation. Although hypertonic saline (7.5% sodium chloride) initially showed promise, a meta-analysis of several studies failed to demonstrate an improvement in survival rates compared to those patients treated with isotonic solutions.85
En route to the receiving facility, the EMS providers should insert two large-bore (14- or 16-gauge) intravenous catheters in veins of the forearm or antecubital area. If possible, lactated Ringer’s solution (or normal saline) should be warmed (102°F/38.8°C) prior to administration. Fluid resuscitation in the prehospital setting must be based on the clinical scenario.44 If the patient has suspected uncontrolled hemorrhage in the thorax, abdomen, or retroperitoneum, fluid infusions should be titrated to maintain a systolic blood pressure (SBP) in the range of 80–90 mm Hg (mean arterial pressure of 60–65 mm Hg) in the hope of perfusing vital organs while limiting the risk of increased, uncontrollable internal hemorrhage. If the patient has a suspected injury to the central nervous system injury (TBI or injury to spinal cord), intravenous fluids should be administered at a rate sufficient to maintain the SBP at 90 mm Hg. If the patient has identifiable shock that resulted from external hemorrhage that has been controlled, fluids are titrated to maintain a normal pulse rate and blood pressure. If the patient again becomes hypotensive, further intravenous fluids should be titrated to maintain an SBP in the range of 80–90 mm Hg.
Controversy exists regarding the role of therapy with intravenous fluids in the prehospital setting. No published study has ever demonstrated an improvement in survival resulting from the prehospital administration of fluids. One computer model of prehospital fluid therapy suggested that intravenous therapy is potentially beneficial when all of the following occur: (a) the bleeding rate is initially 25–100 mL/min; (b) the prehospital time exceeds 30 minutes; and (c) the intravenous infusion rate is approximately equal to the bleeding rate.86
Opponents of prehospital fluid therapy cite data from animal models of uncontrolled internal hemorrhage. In these studies, attempts to improve blood pressure with crystalloid infusions have resulted in increased blood loss and mortality.87–90 Data from a prospective, randomized prehospital trial of intravenous fluid therapy in patients with penetrating torso trauma found an improved outcome when intravenous fluids were withheld until operative control of hemorrhage was obtained.91 Unfortunately, there were long delays until operation was performed in this study. Several blood substitutes that have shown promise in the laboratory have encountered difficulty in clinical trials, and none has been approved for routine use by the FDA.
Although further studies will be needed to clarify this issue, EMS providers should never delay transport simply to initiate intravenous therapy. In one sense, the most important fluid in the prehospital care of critically injured patients is fuel—to transport patients rapidly to the closest appropriate facility.
Secondary survey refers to a more thorough history and physical examination. For the patient with life-threatening conditions identified in the primary survey, the EMS provider performs the secondary survey when those conditions have been addressed and are stable or improving and the patient is being transported. If the primary survey fails to indicate that the injured patient is critical, then the provider proceeds on to the secondary survey.
This brief history from the patient or family includes the following:
• Allergies to medications
• Prescription or over-the-counter Medications
• Pertinent Past medical history
• Last eaten
• Recall of Events leading up to the injury
This complete physical examination begins with obtaining a complete set of vital signs. Injuries to the head, neck, chest, abdomen, pelvis, and extremities are noted. The patient is then turned using the log roll maneuver if spinal injury is suspected, and the patient’s back is examined. Finally, a neurologic examination that involves reassessing the GCS score, pupillary reaction, and motor and sensory functions in the extremities is completed.
Because of the high concentration of blood vessels in the skin and soft tissues of the scalp, face, and neck, even a small wound can result in serious external hemorrhage. EMS providers and other health care workers often fail to appreciate that patients with a complex scalp wound may bleed sufficiently to develop shock. A compression dressing created with gauze pads and an elastic bandage often provides satisfactory control of hemorrhage.
Traumatic Brain Injury
TBI remains one of the leading causes of mortality in injured patients. Secondary brain injury refers to the extension of the original injury and may result from numerous causes. These include hypoxia, hypocapnia and hypercapnia, anemia, hypotension, hypoglycemia and hyperglycemia, seizures, and intracranial hypertension as the result of edema or mass effect. Optimal prehospital care of the patient with TBI involves preventing secondary brain injury, maintaining cerebral perfusion pressure (mean arterial pressure minus intracranial pressure), and expeditious transfer to a facility capable of caring for the injury.
A patient with a severe TBI may be unable to control his or her airway, and endotracheal intubation should be considered for patients with a GCS score of 8 or less, although an alternative airway device may provide a satisfactory airway. Ventilatory support should be administered and the patient maintained eucapneic as prophylactic hyperventilation is no longer indicated.92,93 Data from patients with TBI indicate that those who arrive in the emergency department with either hypocapnia (arterial ) or hypercapnia have poorer outcomes compared to those who arrive in a eucapneic condition.94 Unfortunately, capnography has not proven to be a useful noninvasive method for keeping a patient in the target pCO2 range. Warner et al.95 found a poor correlation between ETCO2and arterial pCO2, especially in patients with impaired perfusion.
Blood loss should be minimized by controlling external sources and splinting fractures as appropriate. Because of the risk of an associated injury to the spine, patients with suspected TBI should undergo spinal immobilization. Intravenous fluids should be initiated en route to the receiving facility with a goal of maintaining the SBP at 90 mm Hg. During prolonged transport, blood glucose can be monitored and dextrose administered if the patient is hypoglycemic. Benzodiazepines are appropriate for control of seizures, but they should be carefully titrated intravenously because of the risk of hypotension and respiratory depression.
Intracranial hypertension may cause cerebral herniation and brain death, but it cannot be measured in the prehospital setting. Signs of possible intracranial hypertension include the following: a decline in the GCS score of 2 points or more, development of a sluggish or nonreactive pupil, development of hemiplegia or hemiparesis, or Cushing’s phenomena (bradycardia associated with arterial hypertension). An algorithm for the prehospital management of TBI has been developed (Fig. 7-5).44
FIGURE 7-5 Algorithm for the prehospital management of TBI. (Reproduced with permission from Salomone JP, Pons PT, McSwain NE, eds. PHTLS: Prehospital Trauma Life Support. 7th ed. St. Louis: Mosby; 2011:240. Copyright © Elsevier.)
Flail Chest and Pulmonary Contusion. In the prehospital setting, the administration of oxygen and ventilatory support are the primary therapies for a flail chest and suspected pulmonary contusion (see Chapters 24–26). Oxygen saturation should be kept at 95% or higher by applying supplemental oxygen. CPAP, a therapy which is becoming increasingly common among EMS services, may be of benefit. If these measures fail to provide adequate oxygenation, ventilations should be assisted and endotracheal intubation considered if the patient’s tidal volume appears inadequate.
Tension Pneumothorax. Tension pneumothorax should be suspected whenever the following three criteria are identified: increasing respiratory distress or difficulty ventilating with a BVM device, decreased or absent breath sounds, and hemodynamic compromise. Needle decompression of the pleural space can be lifesaving.44,96,97 The intravenous catheter inserted should be left in place, but there is no need to create a one-way (“flutter”) valve as any air exchange through the catheter is clinically insignificant. Recent data suggest that a catheter length of at least 8 cm is necessary to reach and decompress the pleural space.98–100
Open Pneumothorax. An open pneumothorax should be sealed with an occlusive dressing. One of the four sides of the dressing may be left untaped so that air can decompress from the pleural space as needed. After an occlusive dressing has been applied to an open pneumothorax, any signs of a developing tension pneumothorax should prompt the EMS worker to remove the dressing. If this does not result in improvement of the patient’s status, needle decompression should be considered.
Pericardial Tamponade. Pericardial tamponade is generally encountered following penetrating trauma to the heart; however, it may be a complication of a blunt cardiac rupture. In the prehospital setting, the classic symptoms of Beck’s triad (elevated venous pressure, muffled heart tones, and hemodynamic compromise) may be difficult to identify. While some EMS systems permit ALS personnel to perform pericardiocentesis if pericardial tamponade is suspected, the emphasis should be placed on transporting that patient with a suspected tamponade to a facility that has immediate surgical capabilities.
Intra-Abdominal Hemorrhage. In the absence of an obvious sign such as a bullet wound, intra-abdominal hemorrhage is difficult to identify in the prehospital setting, especially in the unconscious trauma patient (see Chapters 27–34). Unexplained hypovolemic shock should lead the EMS provider to suspect this condition. Management involves rapid transport to a facility that offers immediate operative intervention.
Pelvic Fractures. The presence of a severe pelvic fracture may be suspected if the EMS provider finds instability on examination of the pelvis, especially if the patient has evidence of hypovolemic shock (see Chapter 35). Pelvic binders, which are often placed on hypotensive trauma patients with proven pelvic fractures in the hospital, have limited utility in the field. EMS providers may not be able to identify a fractured pelvis on physical examination alone and the pelvic binders are costly. These binders may be useful in the setting of a hypotensive trauma patient with a known pelvic fracture who requires interfacility transport.
Pregnancy. Prehospital management of the injured pregnant patient focuses on adequately resuscitating the mother, especially if shock is present (see Chapter 37). In the third trimester, pregnant individuals may exhibit hypotension while lying supine due to compression of the inferior vena cava by the uterus. Supine hypotension is treated by gently rolling the mother into the left lateral decubitus position or, if immobilized on a long backboard, placing sufficient padding under the right side of the board to elevate it 30° or so. If hypotension does not correct with this measure, hemorrhagic shock should be suspected. Oxygen should be administered, and the patient transported to a facility that has both trauma and obstetrical capabilities.
An algorithm has been developed that details the indications for spinal immobilization in the prehospital setting (see Chapter 23) (Fig. 7-6).44,101 Patients with penetrating trauma to the torso almost never have an unstable vertebral column.102 A recent analysis of data from the National Trauma Data Bank showed that victims of penetrating trauma who received prehospital spinal immobilization had a higher risk of death compared to those who did not.103Therefore, spinal immobilization is indicated in the setting of penetrating trauma only when the patient has a neurologic complaint or finding. In patients with blunt trauma, spinal immobilization should be performed if the patient has an altered level of consciousness (GCS score < 15) or if spinal pain or tenderness, a neurologic deficit or complaint, or an anatomic deformity of the spine is present. In the absence of these findings, the mechanism of injury should be evaluated. If the mechanism is considered to be concerning, the patient should be evaluated for evidence of alcohol or drug intoxication, presence of a distracting injury, or the inability to communicate. If any of these are present, spinal immobilization should be performed. In their absence, spinal immobilization is not indicated.
FIGURE 7-6 Indications for spinal immobilization. (Reproduced with permission from Salomone JP, Pons PT, McSwain NE, eds. PHTLS: Prehospital Trauma Life Support. 7th ed. St. Louis: Mosby; 2011:257. Copyright © Elsevier.)
Hemorrhage. This is the only immediately life-threatening condition associated with trauma to an extremity (see Chapters 39–41). External hemorrhage should be controlled with direct pressure or a pressure dressing, followed by a tourniquet if these measures fail. Internal hemorrhage is best managed in the field by immobilization of the extremity. In the critically injured patient, immobilization to a long backboard is sufficient stabilization. If the patient does not have life-threatening injuries, time can be taken to splint each suspected fracture individually. A traction splint provides reasonable pain control and will stabilize a suspected fracture of the femur.
Amputation. The ACSCOT has published guidelines for the management of amputated parts.104 These include the following:
• Cleansing the amputated part by gentle rinsing with lactated Ringer’s solution
• Wrapping the part in sterile gauze moistened with lactated Ringer’s solution and placing it in a plastic bag
• Labeling the bag or container and placing it in an outer container filled with crushed ice
• The part should not be allowed to freeze, and it should be transported along with the patient to the closest appropriate facility.
Pain Control. In the prehospital setting, analgesics are indicated for an isolated injury to an extremity, but not in a patient with multisystem trauma.44,105,106 After appropriately splinting the extremity, small doses of narcotics, titrated intravenously, may help relieve pain. The patient should be observed for side effects including hypotension and respiratory depression. Narcotics should not be administered in the trauma patient who exhibits signs of shock or when the patient appears to be under the influence of drugs and alcohol.
Disasters may be the result of natural phenomena, such as tornadoes, hurricanes, and earthquakes, or man-made in the case of a building collapse or terrorist event. When situations such as these occur, the EMS and health care systems must try to match their resources with the needs of the community. A multiple-patient incident refers to a situation where numerous individuals may be injured, but the EMS system possesses the ability to provide adequate care. In a mass casualty incident, the number of injured patients overwhelms the resources of the community, and additional aid from other locations is required. The number of patients involved in each of these circumstances may vary, depending on the size of the EMS system and the resources of the community.
In either situation, EMS personnel and health care workers must employ the principles of triage in order that the most seriously injured patients receive care before those with minor injuries. Simple Triage and Rapid Treatment (START) is an easily taught, simple triage system that is widely used by EMS providers when faced with numerous injured patients.44,107,108 A national expert panel, assembled by the CDC, reviewed all available triage schemes (“SALT”) and proposed a new method, comprised of the best components of the others.109 A more comprehensive discussion of disaster care is presented in Chapter 8.
Over the last decade the entire health care field has seen a growing trend toward evidence-based medicine. EMS, in general, and prehospital trauma care, specifically, need quality research to separate sound medical practice from conjecture. Management of the airway and fluid therapy are two areas that deserve intensive investigation in the prehospital setting. Far too few treatment protocols in EMS are based on high-quality data. More commonly, protocols are written that include the biases of the authors and extrapolations from inhospital care.
Several major obstacles to the development of quality EMS research exist.14 Funding is woefully inadequate and integrated information systems are needed to link data on patient care with information on outcome. Few academic institutions possess a long-term commitment to EMS research. Governmental regulations regarding informed consent inhibit the conduct of research in the emergency situation, as well. Finally, EMS personnel lack an appreciation of the importance of research in their own field. As these challenges are overcome, new research will lead us to better care for our patients. NHTSA has published a document detailing numerous issues in prehospital care that are awaiting investigation.16
SUMMARY AND GOLDEN PRINCIPLES
Prehospital management of the injured patient remains a topic of some debate. Few experts recommend a return to a mere “scoop and run” approach in which EMS personnel would leave the patient without support of vital functions during the transport to the hospital. Conversely, delays on the scene to perform unnecessary interventions are associated with increased mortality.83,103 A recent publication compared trauma mortality before and after the implementation of a province-wide ALS program and found no significant change in survival between the two periods.110 While these findings could be the result of inexperienced ALS providers or inappropriate ALS protocols, it remains unclear which, if any, ALS procedures improve survival.
A more moderate approach focuses on limited, key field interventions, as taught in the PHTLS program:
• Rapid assessment to identify life-threatening injuries
• Key field interventions including management of the airway, ventilatory support with administration of oxygen, control of external hemorrhage, etc.
• Rapid transport to the closest appropriate facility
PHTLS summarizes optimal prehospital trauma care into 14 golden principles (Table 7-4).44 One study from Trinidad and Tobago compared the overall mortality of trauma patients following the introduction of PHTLS training with the period preceding PHTLS. The authors documented a decrease in mortality of about 33% following the PHTLS training of EMS personnel.111
TABLE 7-4 Golden Principles of Prehospital Trauma Care
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