Early EMS Radio Communications
Despite the availability of a number of designated radio frequencies for public use, a 1970 study showed that less than 5% of ambulances had a mobile radio. In the seminal white paper, "Accidental Death and Disability," one recommendation spoke of the need for dedicated frequencies for EMS: frequencies to be used between the ambulance and the hospital as well as between the dispatch center and the ambulance. Another recommendation advocated for a centralized radio and telephone communications center. During that era, it was not uncommon for a citizen to either call the operator for help or call a seven-digit emergency hotline. These hotlines, dedicated telephone numbers, usually rang into someone’s house. That person would then use a call-down tree to summon an emergency crew. Some hospitals still maintain an emergency hotline (Figure 18-11) as a backup to radio communications. While other emergency notification systems also evolved, they all had one thing in common: inefficiency.
The final recommendation of the white paper called for the creation of a single nationwide telephone number for all emergency services. The practice at the time was that every jurisdiction had its own seven-digit emergency telephone number. Unfortunately, the telephone company’s service area did not always line-up with the boundaries of a particular EMS service. This resulted in frequent errors.
Despite the recognition of communications as an integral component of EMS and a growing public awareness of the importance of communications to the "chain of survival," EMS communications continue to be problematic.
Figure 18-11 Dedicated emergency hotline.
Phases of EMS Communications
There are three phases of communication in every EMS incident: (1) the occurrence and the detection of the occurrence, (2) the notification and response of responders, and (3) the treatment and transportation of the patient. Delays due to communications problems during any one of these three phases can result in increased harm, and even death, for the patient.
Detection
In 1967, the President’s Commission on Law Enforcement and Administration of Justice recommended that there be a single universal emergency number in the United States. Britain had used a national three-digit emergency number, 9-9-9, since 1937 and had a great deal of success with a universal number. In November of 1967, the FCC and the American Telegraph and Telephone Company (AT&T) announced that AT&T would use 9-1-1 as its universal emergency number in all of the areas served by AT&T. The number 9-1-1 was chosen, in part, because no exchange or area code in the AT&T system used the number 9-1-1.
Figure 18-12 Communciations center or public safety access point.
Shortly thereafter, on February 16, 1968, Representative Rankin Fite, Speaker of the House of Representatives, placed the first 9-1-1 call in Haleyville, Alabama. Since that fateful first call, 9-1-1 service has been extended to over 96% of the United States. Canada has also adopted the 9-1-1 emergency number, making it an international emergency number.
When a 9-1-1 call is placed, a specially trained "call-taker" takes down information regarding the nature of the emergency to pass along to fellow workers or responders. The entire 9-1-1 operation is generally located in a centralized communications center called a public safety access point (PSAP) which runs 24 hours a day, seven days a week (Figure 18-12).
Subsequent generations of 9-1-1 service have been enhanced (E9-1-1) to include a call-back feature as well as location identifier. These features allow emergency communications specialists (COMSPEC) to dispatch emergency responders to people who are unable to speak or who have lapsed into unconsciousness.
At its inception, 9-1-1 service was very effective in getting help to those in need of assistance. However, the widespread use of mobile cellular telephones has reduced some of the advantages of the E9-1-1 system. Communications specialists receiving a 9-1-1 call from a cellular telephone do not have a call-back number nor do they have a location identifier to assist them with rushing aid to the patient’s side. Recognizing this problem, the telecommunications industry has agreed to rectify the problem in two phases. During phase I, cellular telephones will not only provide a call-back number to the PSAP but also provide the location of the transmitting tower. During phase II, the cellular telephone will be able to emit a location finder, a homing beacon of sorts, which multiple towers can use to triangulate the position and give the cellular telephone’s exact location in terms of latitude and longitude.
Prearrival Instructions
In 1975, Phoenix firefighter Paramedic Bill Tune successfully coached a woman while she performed CPR on her infant. After reviewing the incident, Chief Allen Brunacini of the Phoenix Fire Department ordered that callers receive instruction on how to self-rescue before responders arrived. Most current EMS dispatch procedures include some form of prearrival instruction. This instruction, called medical self-help, added another dimension to the role of communications specialists—being the "first" first responder.
Notification and Response
The next phase of emergency communications is the notification phase. During the notification and response phase, the greatest danger is posed for a Paramedic. Using the lights and siren in response to an emergency, the Paramedic is at risk of bodily harm secondary to motor vehicle collision. This danger is accepted in light of the potential good which can be created by prompt treatment of the patient as well as the fact that the danger can be mitigated by the cautious operation of the emergency response vehicle. Nevertheless, in many cases, Paramedics and the public are put in harm’s way during a call for assistance in which a delayed response would not harm the patient. Concerned about the widespread practice of sending all EMS units out with lights and sirens on to the scene regardless of the nature of the emergency, in 1977 Dr.Clawson went about systematically placing EMS calls in a priority classification.
Dr. Clawson’s objective was to send the right response to the right person at the right time. Original trials of the new Medical Priority Dispatching™ were successful in Salt Lake City, Utah, and the system proliferated across the United States and Canada.22,23 According to emergency medical dispatch (EMD) protocols, the communication specialist was to interrogate the caller, give prearrival instructions, and use preset criteria to make a response determination before dispatching the appropriate EMS responder units.
The use of EMD has become so widespread in the United States that the American Society of Testing and Materials (ASTM) issued a practice standard in 1990. In addition, the National Association of Emergency Medical Services Physicians (NAEMSP) advanced a position paper that essentially states that EMD is the standard of care for dispatching EMS calls.
First-Due Report
Almost all Paramedics notify the PSAP of their departure from their assigned post or station and their arrival on-scene. In some cases, particularly where there are multiple casualties, a first-due report is important for scene command and control. A first-due report is a brief synopsis of the scene size-up obtained by the first arriving EMS responder. Typically it includes the exact location of the call, the nature of the incident, known or suspected hazards, and the anticipated number of patients. If special resources (e.g., heavy rescue) are needed, they would be requested at that time.
In the 1920s, police officers used 10-codes. These police departments often had one radio frequency and used 10-codes as abbreviated messages designed to minimize airtime. In 1940, the Associated Police Communications Officers, now the Association of Public Safety Communications Officials (APCO), published its first 10-code list. Since that publication, and despite efforts at standardization, dozens of versions of the 10-code have been created. These 10-codes are useful when only used intradepartmentally; however, the use of 10-codes can be confusing in cross-jurisdictional communications, and especially to responding mutual aid companies that do not use the same codes. Therefore, many EMS systems and disaster planners prefer the use of plain English transmissions and discourage the use of 10-codes.
Radio Conduct
While plain English transmissions can be clear, the ability to use plain English has caused some emergency personnel to take free license and use vulgarity over the air. The FCC has the authority to fine, suspend, or terminate any radio license for failure to comply with the standards for radio operation, including the misuse of radio or use of profanity while on-the-air. As a result, and as part of the culture of EMS, a characteristic form of spoken communication has arisen. Frequently, Paramedics will use a standard nomenclature, such as the terms "affirmative," "negative," and "stand-by," as well as the use of concise radio reporting style, to ensure that a clear message gets through. It is also common for Paramedics to suspend pleasantries, such as saying "please" or "thank you" during a transmission. There is an implicit understanding among Paramedics that the Paramedic is both courteous and professional when foregoing the use of pleasantries in favor of conserving airtime.
Treatment and Transportation Communications
The Paramedic shares a special relationship with an emergency physician that requires a more complete disclosure of the patient’s condition than would be expected from an EMT. This duty is owed, in part, because of the invasive procedures that a Paramedic is allowed to perform. Typically, when a Paramedic is contacting medical control for guidance and instruction, the report begins with the Paramedic’s identifier. Many systems assign numbers to Paramedics which indicate that the person on the radio is a recognized Paramedic with clinical privileges. The following format is an example of a standardized radio report. Each EMS system varies with regard to the information required and the order of presentation.
Starting with patient demographics (age, sex, and weight in kilograms) and the patient’s chief concern (in the patient’s own words, if possible), the Paramedic would provide a history of the present illness (HPI). Mnemonics such as AEIOU TIPS or PQRST can be helpful in organizing the mass of patient health information into a meaningful whole.
What follows is the patient’s past medical history (PMH). The mnemonic AMPLE can be useful for organizing the patient’s information. While advising the physician about every allergy, every medication, and the patient’s complete past medical history may appear helpful, this amount of information may serve to only confuse the physician who is trying to understand the underlying problem. A Paramedic uses judgment to select the information that is pertinent to share with the physician in order to optimize time and increase efficiency.
The Paramedic would then proceed to the physical examination. Paramedics will have already completed an initial survey. If the patient is high priority, then all life-saving interventions should be conveyed to the physician in a standard ABC order. Provided that all life-threatening conditions have been treated and temporarily stabilized, the Paramedic would then proceed to report the patient’s vital signs: temperature, pulse, respirations, and blood pressure. Following the initial assessment and vital signs, the Paramedic should report the findings of a focused/vectored physical examination (PE). The Paramedic understands that he is the emergency physician’s eyes and ears in the field. The Paramedic should anticipate what observations the physician will likely request. Clinical practice, working side-by-side with the emergency physician, can help educate the Paramedic as to the expectations that a physician will have for a physical examination report.
In the case of a medical patient, the history of present illness plays a pivotal role in the decision-making process. In the case of a trauma patient, the mechanism of injury coupled with the physical examination findings is of paramount importance. Paramedics learn through experience to emphasize the appropriate findings according to the patient’s presentation. Once the patient presentation is complete, it is appropriate for the Paramedic to make a field diagnosis of the patient’s condition. Providing a field diagnosis over the radio helps the emergency physician understand the Paramedic’s direction and intent. At this time, the EMS physician can ask for more assessment findings, both history and physical, as well as redirect the Paramedic’s attention to alternative conclusions.
What follows is usually a discussion of the treatments provided up to that point in time, including their effect, and a dialogue about how to proceed. Whenever a Paramedic accepts a medical order, he or she should practice the echo technique. With echo technique, when the physician gives an order the Paramedic should repeat the order back to the physician exactly as received. The physician should then confirm the accuracy of the read-back.
To prevent confusion, some EMS systems only allow a Paramedic to accept one order at a time. Stacking orders, each received one at a time, is acceptable provided that adequate time is permitted between interventions to assure that the therapeutic goal has been met, or not met as the case may be, before proceeding.
Many systems also require an alert report be sent to the triage station or a charge nurse. In some EMS systems, the Paramedic is tasked with alerting the receiving facility. The information in the alert report is brief and concise: age, sex, chief complaint, mental status, vital signs, treatments in progress, and an estimated time of arrival (ETA).
Radio Difficulties
Paramedics frequently encounter problems while trying to operate their radio systems. The Public Safety Wireless Network study indicated that some 15% of public safety providers had problems with static, batteries, or both, while another 23% complained of signal fading. Despite the fact that 24 more mHz of bandwidth has been dedicated for public safety use, some 32% of public safety providers complained about channel crowding.
The question of interagency interoperability is important in the post September 11, 2001 era. It is imperative that all public safety agencies be able to communicate with one another in order to more efficiently carry out their mission with the maximum degree of safety. The Fire and EMS Communications Interoperability study indicated that less than 35% of the agencies surveyed—some 1,045 agencies nationwide—indicated confidence in the interoperability of their radios during a large scale task force operation typically seen at a multiple casualty incident.
Conclusion
Whether communicating with other members of the healthcare team or the public safety team, the quality of communications is important to overall teamwork. Working as a team, and optimizing communications at both levels, will help facilitate patient care and the patient’s recovery from a medical emergency.
key points:
• Paramedics are a part of both the public safety team and the healthcare team. Communication within the public safety team, made up of law enforcement officers, firefighters, and Paramedics, serves to provide safety to the rescuer, the public, and the patient.
• The Paramedic’s communication with the healthcare team serves the patient’s interests by providing the patient’s past medical history, information about the history of the patient’s present illness, and the patient’s response to prehospital treatment.
• Communication occurs between team members as well as with other teams.
• Interfaces can occur in both oral and written forms.
• AM and FM radio signals are generated through modulation techniques which modify a wave by either changing the wave’s height (amplitude modulation [AM]) or by changing the wave’s speed (frequency modulation [FM]). The message can then be carried through antennas to be transmitted.
• The antenna’s length is a function of the wave’s length; therefore, an antenna correctly matched to a radio greatly improves radio transmission. The difference in radio waves is not in the speed but rather in the frequency of the waves in the radio transmission, measured in cycles per second or Hertz.
• To overcome obstacles in the line of sight that can block transmissions, high-frequency radio waves are directed toward the atmosphere and the signal is reflected back to Earth, covering great distances with great quality.
• The principal radio frequency band used by emergency services is very-high frequency (VHF). VHF, from 30 to 300 mHz, can be cleanly transmitted over 25 to 50 miles.
• To overcome the problem of distance, repeaters-which pick-up, amplify, and then retransmit a radio transmission-can extend the range of a VHF almost indefinitely.
• Two radio architectures exist in EMS today: traditional land mobile radio (LMR) architecture and cellular system architecture.
• The simplest radio system, simplex (or a walkie-talkie), only allows communication in one direction at a time.
• A duplex radio is similar to a landline and uses two frequencies. One frequency is used to transmit and one is used to receive, allowing an operator to talk and listen at the same time.
• Multiplex radios permit the transmission of both audio signal as well as data such as telemetry.
• To reduce channel crowding, computers allow multiple users to communicate over fewer frequencies by selecting the frequency to be used based on availability, a process called trunking.
• Cellular telephones are actually low-powered wireless transmitters (radios) that work within close proximity of a radio tower.
• Technology today allows Paramedics to use laptop or handheld computers along with personal digital assistants (PDA) before, during,and after calls to gather, transmit, and receive critical patient information using cable or wireless technologies.
• The Communications Act of 1934 granted the Federal Communications Commission (FCC) control over all civilian use of radios.
• The 9-1-1 system that we use today, which covers over 96% of the United States, was adapted from the British 9-9-9 national emergency number and initially put in place by AT&T.
• The first phase of communication in an EMS incident is a call received at a centralized communications center or public safety access point.
• The next phase of emergency communications is the notification and response phase.
• The third phase of emergency communications is the treatment and transport of the patient.
• Paramedics need a formalized radio report method.
