Introduction

One of the most important roles of emergency medical services (EMS) 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 the advantages and disadvantages of casualty evacuation, along with when it may 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 medicine paradigm 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 1 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 care delivery 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 on 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 radical advancements, including organizing the first ambulance corps, dedicated litter-bearer teams during battles, and educating nursing care for 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 en 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. They presumably got 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 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 possible, preferred, and necessary.[3][4]

Clinical Significance

It is important to recognize when and how casualty evacuation occurs and understand the limitations and challenges this can present. The following are 2 common situations that demonstrate this point. Police are often the first to arrive at a scene. During shootings, many police officers 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, which they would in the back of an ambulance in either of these scenarios.

For several decades, trauma centers and the military have utilized the "Platinum 10 Minutes" and "Golden Hour" rules to guide planning for protocols and emergency disaster responses. The general principles include on-scene stabilization for no more than 10 minutes before 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, mutual aid compacts, and disaster plans, are managed in such a way as to facilitate meeting these goals, not just for trauma but for medical emergencies as well. Resources are finite. When ambulances are unavailable, medical providers must appropriately utilize casualty evacuation, and planners must account for their use.

From the receiving end, hospitals and medical facilities must anticipate that patients arrive by casualty evacuation. This probably means 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 that it has 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. 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. For instance, ambulances may bypass a slightly closer facility for a more appropriate one. One center may be PCI capable of 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, 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 is marginally closer or unaware of the differences. Those facilities subject to the Emergency Medical Treatment and Labor Act must appropriately stabilize the patients and perhaps arrange a transfer to another facility if appropriate.[8][9][10]

Those responsible for moving patients from 1 scene to another must also be aware of the pros and cons of casualty evacuation. EMS personnel, first responders, disaster planners, and anyone else tasked with evacuating patients must recognize all the available options. The key to every scenario, both planned and impromptu, is understanding 3 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.

Using local, on-scene resources such as cars or trucks to move patients may be the most efficient and appropriate for a given scenario. If reliable personnel are abundant 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. Appropriately using casualty evacuation can be a major asset in improving patient care.[11][12][13]