Introduction

One of the most important emergency medical services (EMS) roles is in-transit medical care for patients. It has transformed the role of the EMS provider from the “ambulance driver” in the early days of the specialty to the modern professional with varying scopes of practice and protocols. It has helped to reduce morbidity and mortality and extended the reach of medical care out away from the hospital setting. However, there are many situations when traditional medical evacuation is not feasible, possible, or ideal.

Casualty evacuation can be defined as the movement of the sick or injured by means other than those designed for medical transport and in which in-transit medical treatment is limited or unavailable. Recognizing advantages and disadvantages of casualty evacuation along with when it will or potentially be utilized is essential for the EMS professional in planning for, moving, or receiving patients and implementing proper policies and training for its optimization.

Issues of Concern

The old paradigm of medicine included bringing the medical providers to the sick and wounded rather than bringing patients to providers. This made the most sense in small, close-knit communities where the risk of communicable diseases was higher if patients were clustered, even if it was not cognitively recognized as such. Transportation and infrastructure were also generally limited; therefore, moving one person around made more sense than the intricate networks established in most modern systems. Furthermore, medicine was not logistically intensive, requiring simple, often unclean, tools, and ingredients for the remedies of the day. Interestingly, there is an increasing movement toward home delivery of care in modern healthcare delivery models, with advanced EMS systems leading this charge.

In those instances where home care was not possible, or patients remained at risk if they stayed in place, such as a battlefield, casualty evacuation remained the only means of evacuation for patients until very recently in medical history. The Crimean and American Civil wars brought out radical advancements, including organizing the first ambulance corps, dedicated litter-bearer teams during battles, and educated nursing care for those brought to casualty collection points and field hospitals.[1] As time and wars advanced, care was pushed further into the field with first aid, analgesia, and preventive medicine provided during the evacuation (now considered the standard of care), giving rise to mobile advanced life support and critical care teams providing expert treatment in route.[2]

Many do not recognize that casualty evacuation is still present and often plays a vital role for patients in medical systems. Every time someone drives their loved one to the emergency department while they have a heart attack, they are technically performing casualty evacuation. Historically, the patient did not receive intravenous (IV) fluids, an electrocardiogram, or other standard treatments such as aspirin and nitroglycerin – all typical in modern medical evacuation. What they did presumably get was timely transportation to a higher level of care.

Any means of conveyance can be utilized for casualty evacuation –  dragging patients out of a danger zone, personal vehicles, watercraft, city buses, and attack helicopters that pick up the wounded on their way out of an engagement area.

Recent mass casualty events have demonstrated the resourcefulness of the public and first responders when trying to remove patients from the scene of an incident. During the Las Vegas mass shooting of 2017, more patients were brought to emergency departments by crowdsourced ride services similar to taxis than by ambulance. There were known pickup locations near the event with cars and drivers waiting. This occurred not because the system failed but because patients and the public were trying to do everything to get away from a horrific scene as quickly as possible. Even with mutual aid assistance and activation of emergency protocols, there were simply not enough ambulances to handle an event of that scale. One can imagine several scenarios in which local resources are exhausted, and the systemic use of casualty evacuation is not only possible but preferred and necessary.[3][4]

Clinical Significance

Recognizing when and how casualty evacuation occurs, it is important to understand the limitations and challenges this can present. The following are two common situations to demonstrate this point.

Police are often the first to arrive at a scene. During shootings, many police officers will provide first aid on-site such as applying a tourniquet and then driving the patient themselves to the ED.[5] Similar situations are also arising with the recent opioid epidemic after first responders administer naloxone and again transport immediately.[6]

While first aid and treatment were appropriately provided, patients do not continue to receive medical care and reevaluation in the back of the police squad car that they would in the back of an ambulance in either of these scenarios.

Trauma centers and the military have utilized the "Platinum 10 Minutes" and "Golden Hour" rules to guide planning for protocols and emergency disaster responses for several decades. The general principles include on-scene stabilization for no more than 10 minutes prior to beginning evacuation to definitive care and arrival at a qualified care facility that can treat surgical injuries within an hour of a traumatic event. Recent reviews have cast doubt on the validity of the specifics for these time frames, but there is little disagreement that evacuation should not be needlessly prolonged.[7] Resources in many areas such as ambulance crews and mutual aid compacts and disaster plans are managed in such a way as to facilitate meeting these goals, not just for trauma but medical emergencies as well.

Resources are finite. When ambulances are not available, medical providers must utilize casualty evacuation appropriately, and planners must account for their use.

From the receiving end, hospitals and medical facilities must anticipate that patients will arrive by casualty evacuation. This probably means that the receiving facility did not receive a report of inbound patients. It is also likely that evacuation triage was not completed on the scene to ensure the sickest arrived first. When receiving patients, the facility must ensure they have a system in place that allows for rapid triage of all patients arriving by all means.

Patients also may not be taken to the most appropriate facility to start with. There may be multiple facilities within proximity of one another, and each is designed in certain ways that medical evacuations with ambulances use to their advantage. Ambulances may bypass a slightly closer facility for a more appropriate one, for instance. One center may be PCI capable for a STEMI, and another facility is a stroke center with TPA and neuro intervention readily available. Medical evacuation crews can do this because they are aware of the differences and continually reassess their patients and manage interventions, allowing them to make on the fly decisions and utilize online medical direction to redirect if necessary. The public, which utilizes casualty evacuation, may not be able to do this and proceed directly to another center because it was marginally closer or simply unaware of the differences. Those facilities subject to Emergency Medical Treatment and Labor Act (EMTALA) must appropriately stabilize the patients and perhaps arrange a transfer to another facility if appropriate.[8][9][10]

Those responsible for moving patients from one scene to another must also be aware of the pros and cons of casualty evacuation. EMS personnel, first responders, disaster planners, and anyone else who may be tasked with evacuating patients must recognize all the available options. The key to every scenario, both planned and impromptu, will be understanding three essential components: 

1. An honest appreciation of the current situation
2. Knowing all the available resources and their capabilities
3. Understanding the desired end state and effective communication of the same.

The decision to use local, on-scene resources such as cars or trucks to move patients may be the most efficient and most appropriate for a given scenario. If reliable personnel are in abundance, but medical transport vehicles are in short supply, a system can be organized to ensure patients are brought to the right facilities. Casualty collection points and ambulance exchange points can also be established to maximize medical transport and personnel effectiveness. These topics will be discussed further in other articles, but the appropriate use of casualty evacuation can be a major asset to improve patient care.[11][12][13]