Tactical En Route Care

Robert T. Gerhardt

OBJECTIVES

After reading this section, the reader will be able to:

Discuss the history of tactical en route care.
Understand basic principles of planning, coordinating, and executing tactical en route care in the context of prehospital trauma life support (PHTLS) tactical combat casualty care.
Be aware of the limitations as well as potential complications that might be encountered in the en route care setting, along with countermeasures to mitigate them.

INTRODUCTION

Over the past century, a revolution in the resuscitative and definitive care of victims of conflict has taken place. In addition to the development of new surgical techniques, resuscitation strategies, pharmaceuticals, and other adjuncts, the military and contingency medicine communities have placed increasing emphasis upon the process of converting the victim into the patient: that is to say, medical evacuation and en route care of combat casualties. The term en route care is defined as “the care required to maintain the phase treatment initiated prior to evacuation and the sustainment of the patient’s medical condition during evacuation” (1). The en route care process involves the medical treatment of injured and ill personnel, during evacuation between levels of care. This may occur at any point beginning with first response and ending with rehabilitative care, if needed.

In civilian EMS circles, air medical transport refers to the use of dedicated aircraft and medical crews, which provide critical care advanced life support or advanced life support (ALS) emergency care and transportation of trauma and medical emergency patients. This service may be provided either from accident sites (scene response) or from primary care centers to tertiary or definitive care (interfacility transfers). Aeromedical evacuation is the commonly applied, but technically inaccurate, term used by the U.S. military for what would otherwise pass as air medical transport (more precisely, “aeromedical” refers to the anatomical and physiological effects of flight on human systems). MEDEVAC, a contraction of the phrase “medical evacuation,” is the U.S. Army’s vernacular for both ground and air medical transport and implies the employment of dedicated vehicles under control of the Army medical department (AMEDD), as well as en route medical care. CASEVAC refers to the process of transporting casualties by any available conveyance and generally implies that no skilled medical treatment is provided en route. Prehospital care is a term that encompasses the emergency care and transport of sick or injured persons in the out-of-hospital setting by varying levels of health care providers. Emergency medical services (EMS) systems are organized and integrated organizations employing air, ground, and even waterborne transport units, staffed by trained emergency medical care providers under the direction and license of a physician medical director, who provides pre- and inter-hospital care. Such systems are usually designated and regulated by state public health or emergency services authorities and are often integrated into regional trauma and cardiac care systems.

To be effective and sustainable, en route medical treatment rendered in the tactical setting of must simultaneously possess the following characteristics: efficacy, simplicity, and facility and tactical validity. Efficacy implies that the procedure or intervention has actually been proven to save lives. It must also be possible to perform such interventions quickly and easily, given rudimentary training and initial proctoring by a qualified instructor. Last, medical interventions in the combat setting should be able to be performed in a fashion that places the patient, the provider, and the transport element at minimal risk for additional injury and that facilitates the most rapid possible extraction from the line of fire. This latter consideration constitutes perhaps the most complicated aspect
of en route combat casualty care, because the majority of published EMS literature to date pertains to civilian settings with well-developed health care systems and relatively short time-distance issues.

TRANSPORT CONSIDERATIONS

Time-Distance and Environment-Of-Care Issues

Traditionally, the primary tenet of en route care has been, “the treatment is speed.” Although medical interventions both at the time of wounding and en route to definitive care have made their impacts, the transport time interval between point-of-wounding and definitive care remains a critical component in the survival of victims of conflict.

The U.S. military refers collectively to the effects of the operational milieu as METT-TC issues: namely, mission, equipment, terrain and weather, time, troops (both yours and your adversary’s) and civilians on the battlefield (2). All of these factors possess the potential to impact, either positively or negatively, an evacuation plan. As such, the prudent en route care provider will, at minimum, be aware of these issues; at best, one will participate in the process of planning the mission with the express purpose of ensuring that medical expertise is integrated into the developing plan.

In the case of most tactical operations, no such formal fronts exist. In addition, hostile forces are divergent in terms of operational capability, mobility and adherence to the law of war (to date, none are formal signatories to the Geneva Conventions). Areas of responsibility (AOR) for allied combat arms and combat support units may be broad and deep, resulting in significantly greater distances required for evacuation. These increased distances coupled with the potentially compounding effects of rough terrain, inclement weather and a broader maneuver area for hostile forces, all conspire to increase the risks inherent in casualty evacuation and en route care. As such, the importance of tactical medical and casualty evacuation preplanning has taken on a new sense of urgency.

Important time-distance considerations in casualty evacuation and en route care include:

Location, number and type of elements supported
Their organic medical support and evacuation assets
Location of echelon II and III CHS (combat health support) units in your respective AOR
Terrain features affecting your potential evacuation routes
Analysis of hostile forces locations, capabilities and limitations, and prior conduct toward noncombatant/medical units
United States or allied maneuver and support elements available to escort or otherwise assist the evacuation mission
Friendly evacuation assets available to you, including dedicated medical evacuation vehicles and aircraft, nonstandard vehicles, potential crew members, and nonmedical attendants
Your source of launch authority

METT-TC information forthcoming from the requesting unit is most readily obtained by receipt of a Standard MEDEVAC Request, usually composed in a nine-line format. An example of a standard MEDEVAC request appears in Table 21.1.

Once armed with this information, the evacuation planner may then determine whether casualties may be evacuated from supported units directly to higher-level care by single sorties or whether ambulance exchange points (AXP) may be required. In addition, rules of engagement and operational plans may be constructed for the employment of air medical and casualty evacuation assets, if available.

The decision whether to employ air medical evacuation appears initially simple in the sense that all immediate and urgent surgical casualties should be evacuated preferentially by air. The decision to employ air assets in the tactical environment is complicated by numerous issues, including the marked vulnerability of rotary wing aircraft to virtually any modern weapons system, including small arms. This danger is amplified in urban environments, where flight paths and LZ’s often intersect closely with buildings and other structures, which may provide safe haven and a direct field of fire to hostile elements intending to engage the aircraft. A sobering thought to be considered by anyone requesting air medical evacuation is the possibility that their request may result not only in the loss of the casualty’s life, but also those of the air crew in the event of a catastrophic aircraft mishap or combat loss.

Appropriate indications for air medical evacuation include the following:

Casualties meeting criteria for urgent evacuation (loss of life, limb, or eyesight within 2 hours)
Casualties meeting priority evacuation criteria, but for whom other means of evacuation will cause deterioration
Circumstances in which the organic medical capabilities of the supported unit have been rendered ineffective (mass casualty incident, medical element neutralized by hostile action)
Risk of loss of evacuation aircraft and air crew is considered manageable by launch authority

Medical Crew and Patient Safety

Casualty evacuation and en route care possess their own unique mission environment beyond that of the general setting of field operations. Thus, like other operational personnel, the en route care provider should conduct individual, crew and patient care precombat checks and
inspections (PCC/PCI). In addition to standard field equipment, weapons, communications and other logistical considerations, the following unique concerns should be considered and addressed:

TABLE 21.1. Sample US/NATO Standard MEDEVAC Request.

1.	Location of LZ for casualty collection (eight-digit MGRS grid coordinates)
2.	Radio frequency, call sign, and suffix of requesting element
3.	Number of patients by precedence:
	A—Urgent
	B—Urgent Surgical
	C—Priority
	D—Routine
	E—Convenience
4.	Special equipment required:
	A—None
	B—Hoist
	C—Extrication equipment
	D—Ventilator
5.	Number of patients:
	A—Litter
	B—Ambulatory
6.	Security at LZ/pick-up site:
	N—No enemy troops in area
	P—Possible enemy troops—approach with caution
	E—Enemy troops in area
	X—Enemy troops in area—armed escort required
7.	Method of marking LZ/pick-up site:
	A—Panels (VS-17 or similar)
	B—Pyrotechnic
	C—Smoke
	D—None
	^* Additional methods may be listed by local TACSOP
8.	Casualty nationality and status:
	A—U.S. Military
	B—U.S. Civilian
	C—Non-U.S. military
	D—Non-U.S. civilian
	E—Enemy prisoner of war
9.	NBC Conditions (use only if applicable):
	N—Nuclear
	B—Biological
	C—Chemical
	— IN PEACETIME, describe LZ terrain

Have available copies of current professional licenses and certifications.
Dress in layers and bring additional warm clothing (temperature fluctuations may be extreme as a result of ambient weather vs. vehicle compartments, altitude, etc.).
Wear appropriate body and eye armor/protection, as well as a helmet, both for protection from hostile fire as well as accidental injury within the crew compartment of the evacuation vehicle.
Be prepared to furnish safety harness, hearing and eye protection, rain protection, and blankets to patients you transport.
Consider the use of hearing protection when practicable.
Carry multiple forms of personal identification.
Carry or have at hand standard precautions protective supplies.
In the air transport setting, consider avoiding the ingestion of gas-producing foods and beverages such as legumes, cruciferous vegetables, and carbonated drinks for the 8- to 12-hour period before anticipated flight or on-call status, if you are susceptible.
If you are susceptible to motion sickness, consider the use of approved anti-emetic agents (a trial is suggested prior to operational use in order to assess for side effects); nonpharmaceutical approaches that have been reported to possess some efficacy include: fixing gaze on the horizon or other distant object, accupressure bands applied to the wrists, and small meals high in simple carbohydrates. Perhaps the best remedy for motion sickness is acclimatization: the more often you ride in a vehicle or fly, the less likely you are to become motion-sick.

Patient Preparation

The basic precepts of care under fire include rapid extrication of both the casualty and provider from exposure to direct hostile fire, by the most expeditious means available. After this has been accomplished, more formal attempts at pre-evacuation packaging should be undertaken. Such preparations take on increasing importance at the AXP or in those patients who are being transferred from a forward resuscitative surgical element to a CSH. Such “intraoperative” patients will require more detailed preparation in order to ensure that their condition does not deteriorate en route.

Detailed checklists for preparation before, during and after evacuation missions are provided in Tables 21.2, 21.3, 21.4 and 21.5.

EN ROUTE CLINICAL CARE

Clinical “Show Stoppers”—Diagnosis and Treatment

As part of the predeparture patient assessment, or during the evacuation mission, en route care providers must
be constantly vigilant for the presence or development of life-threatening conditions affecting the patients in their charge. Anticipation of these conditions, when followed by appropriate interventions may prevent deterioration prior to arrival at the next level of care.

TABLE 21.2. Predeparture mission checklist.

1.	Assemble your team and gear
	Patient movement items (PMI) Pharmaceuticals Expendable supplies and IV fluids Oxygen Safety equipment Tactical, load-bearing equipment and armor Personal weapons, as appropriate
2.	Coordinate with evacuation vehicle crew regarding:
	Prevailing weather conditions General route Tactical concerns Patient requirements (speed, flight ceilings, if applicable)
3.	Communicate with sending unit/facility
4.	Communicate with receiving unit/facility
5.	Resources needed
6.	Coordinate LZ or AXP location, crew pick-up

The following sections will discuss the circumstances, diagnosis, and treatment of the more common life threats or “show stoppers,” which the en route care provider may encounter.

Acute Airway Compromise

A secure airway with the concomitant ability to support ventilation is the primary requirement for patient survival. As such, the en route care provider must assure airway patency prior to evacuation; otherwise, one must be prepared to mitigate complications in what may be clearly a suboptimal transport environment.

TABLE 21.3. Patient On-site Reception Checklist.^*

1.	EXAMINE the patient.
2.	BRIEF the patient, if possible.
3.	SECURE IVs and other tubes, establish flow control (pressure bag and dial-a-flow device or infusion pump).
4.	EMPTY fluid reservoirs and ATTACH vented bags for air travel.
5.	LABEL, COIL, and SECURE all lines and wires
6.	REPLACE air with sterile solution in all indwelling cuffs and balloons for air travel (crystalloid IV solutions are suggested).
7.	ATTACH monitors and safety gear (ear plugs, straps, seatbelts).
8.	SECURE the patient.
9.	ADMINISTER transport medications and sedation if indicated.
10.	TRANSFER oxygen and all devices to stretcher.
11.	OBTAIN initial and serial vital signs.
^*Performed if tactical circumstances permit.

TABLE 21.4. En Route Care Checklist.

1.	KNOW location of emergency gear.
2.	COMMUNICATE with evacuation vehicle crew.
3.	EXAMINE the patient (again).
4.	MONITOR your oxygen tanks, IV flow rates.
5.	AVOID snaring lines and wires.
6.	OBSERVE monitors, reservoirs, patient.
7.	USE standard precautions.
8.	BOLSTER yourself when using sharp implements.
9.	WEAR seat belts or retention straps.
10.	SIT when you can.
11.	PRACTICE sound and light discipline when possible.

The axiom, “when in doubt, intubate,” is strongly recommended prior to evacuation. In circumstances where this is impossible or impractical, the provider’s goal will shift toward attempting to prevent airway compromise while en route. Toward this end, access to continuous suction, nasopharyngeal (NPA) and oropharyngeal airways (OPA), bag-valve-mask apparatus or portable ventilators, supplemental oxygen, and related airway adjuncts should be confirmed. In addition, a laryngoscope with appropriate straight (Miller style) and curved (MacIntosh style) blades, assorted cuffed and uncuffed endotracheal tubes, tube stylets, and rescue airway devices such as trachealesophageal tubes (Combitube), the laryngeal mask airway (LMA) or a cricothyroidotomy kit should be available and in working order prior to departure.

Advanced airway maneuvers are at best a challenge in the transport environment. Cramped crew/patient compartments, tactical flight or ground maneuver, limited visibility, potentially hypoxic and combative patients, and the risk of hostile fire conspire to make such attempts undesirable except in the most critical circumstances. In the event that unanticipated airway compromise occurs to the transport patient, the provider may find rapid sequence intubation (RSI) to be a valuable tool in the re-establishment of a secure and patent airway. It should be noted, however, that RSI is in itself a procedure fraught with risk and should not be attempted by providers unless they are qualified to perform intubation and possess experience in the use and management of complications associated with intravenous (IV) paralytics, induction agents, and analgesics.

TABLE 21.5. Mission Destination Checklist.

1.	EXAMINE the patient (again).
2.	REPORT patient information on final approach, if you can.
3.	UNLOAD under direction of the flight crew.
4.	AVOID snaring lines and wires.
5.	SECURE weapons with evacuation vehicle crew (if any).
6.	COMMUNICATE with receiving medical and nursing staffs.
7.	DOCUMENT your care and leave a copy.
8.	RECOVER your gear for return, as appropriate.
9.	Have a SAFE trip home.