4.1

Aeromedical Evacuation

Chapter 4

Aeromedical Evacuation

Introduction

Evacuation of injured personnel using aircraft, fixed or rotary

wing, has revolutionized the rapid transport of casualties from

areas where there is either inadequate or no care available to

medical treatment facilities (MTFs) where essential and/or

definitive care can be rendered. While an aircraft can decrease

transport time, the aeromedical environment creates unique

stresses on the injured patient. The following are terms that

describe evacuation of patients using aircraft.

 Casualty evacuation (CASEVAC): The movement of a

casualty from the point of injury to medical treatment by

nonmedical personnel. Casualties transported under these

circumstances do not receive en route medical care; if the

casualty’s medical condition deteriorates during transport,

an adverse impact on the casualty’s prognosis and long-term

disability may result. Traditionally, this situation involves a

helicopter mission returning from the battlefield.

 Medical evacuation (MEDEVAC): The timely, efficient

movement and en route care provided by medical personnel

to the wounded being evacuated from the battlefield to MTFs,

using medically equipped vehicles or aircraft. Examples

include civilian aeromedical helicopter services and Army

air ambulances. This term also covers the transfer of patients

from the battlefield to an MTF or from one MTF to another

by medical personnel, such as from a ship to shore.

 Aeromedical evacuation (AE): Providing USAF fixed-wing

intratheater (Tactical Evacuation [TACEVAC]: from the

combat zone to points outside the combat zone, and between

points within the communications zone) and intertheater

(Strategic Evacuation [STRATEVAC]: from out of the theater
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Emergency War Surgery

of operations to a main support area) movement of sick or

injured personnel, with enroute care provided by AE

crewmembers and critical care air transport teams (CCATTs),

to locations offering appropriate levels of medical care.

 Enroute care: Maintenance of treatment initiated prior to

evacuation and sustainment of the patient’s medical condition

during evacuation.

Medical Considerations for Patients Entering the Medical

Evacuation System

Medical Considerations/Requirements

 Medical evacuation request includes requirement for

surgical equipment and/or providers.

 Patient is sufficiently stabilized for the anticipated mode

and duration of travel.

 Patient’s airway and breathing is adequate for

movement.

 Patient’s IV lines, drainage devices, and tubes are fully

secured and patent.

 Patient at high risk for barotrauma should be considered

for prophylactic chest tube placement before prolonged

aeromedical evacuation.

 Heimlich valves on chest tubes are functioning.

 Foley catheters and nasogastric (NG) tubes are placed

and allowed to drain.

 Patient is securely covered with both a woolen and

aluminized blanket for air transport, cold environment,

or postoperative hypothermia.

 3 litter straps are used to secure the patient to the litter.

 Personal effects and all medical records accompany the

patient.

 The evacuation of a patient is initiated by the surgeon

according to established procedures. The support patient administration personnel normally provide the administrative

details and coordination required to accomplish the

evacuation. Due to differences in the type of evacuation assets

used and their effect on the patient’s medical condition (such
4.3

Aeromedical Evacuation

as flying in the pressurized cabin of an aircraft), patients

entering the USAF AE system must also be validated for

evacuation by the supporting flight surgeon.

 For patients evacuated from Level II MTFs or forward surgical

teams (FST), the brigade surgeon (or designee) determines the

evacuation precedence for all patients requiring evacuation

from that facility. This is done in consultation with the

forward surgical team’s chief surgeon and/or senior nurse.

When a patient is readied for evacuation from the forward

surgical team by USAF assets, the supporting patient movement requirements center (PMRC) should be established at

the earliest possible time. This allows the PMRC sufficient

time to coordinate airlift and patient movement items

requirements.

Implications of Aviation Environment

 General Considerations Prior to Transport.

ο Due to altitude effects, limited mobility, decreased staffing

enroute, and unpredictable evacuation times, the referring

physician should tailor vital signs (VS) monitoring

requirements, and frequency of wound and neurovascular

checks.

ο Some therapies that might not be used in a fixed MTF are

appropriate for AE.

♦ For example, patients with significant medical or

surgical conditions should have Foley catheters, NG

tubes, provisions for IV pain medications, extended

duration IV antibiotics.

ο Consider liberal use of fasciotomies/escharotomies.

ο Consider securing airway with prophylactic endotracheal

(ETT) tube.

ο Wounds dressed for delayed primary closure. Unless

directed otherwise, AE crew should not routinely re-dress

wounds. If a patient develops fever or sepsis enroute,

wounds must be inspected.

ο Casts must be bivalved. If the cast is over a surgical wound

site, “window” the cast to allow for tissue expansion and

emergency access. Document neurovascular checks prior

to and frequently during flight.
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Emergency War Surgery

 Decreased Barometric Pressure.

ο The diameter of a gas bubble in liquid doubles at 5,000 ft

above sea level, doubles again at 8,000 ft, and doubles again

at 18,000 ft. Cabin pressures in most military aircraft are

maintained at altitudes between 8,000 and 10,000 feet. If

an aircraft has the capability, the cabin altitude can be

maintained at lower levels, with increased flight time and

fuel.

 Consider a Cabin Altitude Restriction (CAR) for the

following:

ο Penetrating eye injuries with intraocular air.

ο Free air in any body cavity.

ο Severe pulmonary disease.

ο Decompression sickness and arterial gas embolism require

CAR at origination field altitude. Destination altitude

should not be higher than origination altitude. Transport

on 100% oxygen (by aviator’s mask if available).

 Pneumothorax: Chest tube required, even for small,

asymptomatic lesions. A Heimlich valve or collection system

must be in place prior to patient transfer to the flight line.

 Air Splints: Should not be used if alternate devices are

available. Because air expands at altitude, air splints require

close observation and adjustments during flight.

 Ostomy Patients: Vent collection bags to avoid excess gas

dislodging the bag from the stoma wafer. Use a straight pin

to put two holes in the bag above the wafer ring.

 Decreased Partial Pressure of Oxygen: Ambient partial

pressure of oxygen decreases with increasing altitude. At sea

level, a healthy person has an oxygen saturation of 98%–100 %.

At a cabin altitude of 8,000 ft, this drops to 90%, which corrects

to 98%–100% with 2 L/min of oxygen.

 Neurosurgical Patients: Hypoxia may worsen neurological

injury. Adjust ventilator settings to meet increased oxygen

demands at altitude.

 Gravitational Stress: Traumatic brain injury patients can

experience transient marked increases in intracranial pressure

during takeoff or landing. Patient positioning onboard the

aircraft helps minimize this risk (head forward on takeoff,

head rearward on landing).
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Aeromedical Evacuation

 Thermal Stress: Plan for cabin temperature changes from 15°C

(59°F) to 25°C (77°F) on winter missions, and from 20°C (68°F)

to 35°C (95°F) on summer missions.

 Noise: Exposure to noise can produce problems with

communication and patient evaluation (auscultation is

impossible — use noninvasive blood pressure [NIBP] and

an arterial line). Provide hearing protection. Audible medical

equipment alarms are useless.

ο Decreased Humidity: Airplanes have very low cabin

humidity at altitude. Evaporative losses will increase;

therefore, patients will require additional fluids, especially

those with large burns, and those at risk for mucous

plugging.

 Patient movement in nuclear, biological and chemical (NBC)

environments.

ο Nuclear and chemical casualties must be externally

decontaminated, and time allowed for off-gassing of

residual chemical agent.

ο Movement of biological casualties varies by the nature of

the agent, its mechanism of transmission, and the period

of communicability during the course of illness.

ο Any NBC AE movement may be delayed due to the

following:

♦ Aircraft decontamination time.

♦ Availability of noncontaminated aircrew.

♦ Cohorting of similarly exposed patients.

♦ Quarantinable diseases (eg, plague and smallpox)

require special approval (command and diplomatic)

before AE.

Medical Evacuation Precedences

 Depending on the Service and the type of evacuation assets

used, the timeframes for affecting evacuation differ. Refer to

Table 4-1.
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Emergency War Surgery

Table 4-1. Evacuation Precedences.

Army, Navy,

Movement Marine

Precedence (MEDEVAC) Air Force (AE) Description

Urgent Within 2 h. ASAP Immediate AE to save life,

limb, or eyesight.

Priority Within 4 h. Within 24 h. Prompt medical care not

available locally.

Medical condition could

deteriorate and patient

cannot wait for routine

AE.

Routine Within 24 h. Within 72 h or Condition is not expected

next available to deteriorate significantly

mission. while awaiting flight.

 Concept of Operations. The USAF AE system.

ο Command and control (C2) of casualty movement by air

transport.

ο AE personnel and equipment for inflight supportive

patient care and flight line support operations.

ο Organic communication network for medical facilities and

airlift C2 agencies.

♦ Aeromedical Evacuation Liaison Team (AELT): 4–6

person communication team, usually collocated with

an MTF, to coordinate requests with the AE system.

ο Facilities and personnel at airheads for the administrative

processing, staging, and limited medical care of casualties

entering or transiting the AE system. Patients are normally

held only for 2–6 hours prior to evacuation.

♦ USAF units provide aeromedical staging support

through incrementally sized elements ranging in size/

capability from forward deployed special operations

forces (SOF) to 100-bed facilities.

 Reporting a Patient for AE. Originating physician consults

with local FS to determine the en route care plan and timing

of evacuation.
4.7

Aeromedical Evacuation

Due to the complexity of the AE system, physicians must

identity points of contact (POCs) (local Flight Surgeons

[FSs], AELT, aeromedical staging elements, PMRC); verify

and test lines of communication; and rehearse patient

evacuation drills and procedures, before the actual need

arises.

 Patient Stability. Patients validated for transport by AE must

be stabilized as well as possible (secure airway, controlled

hemorrhage, treated shock, and immobilized fractures).

ο Communicate the condition, AE category (ambulatory or

litter), and movement precedence (Table 4-1) of the patient

to the PMRC, as communications assets allow. See PMRC

contact information below.

Commercial Military

PMRC telephone number telephone number

Global-Scott AFB, IL 1-800-303-9301 or DSN 779-4200 or 8184

1-800-874-8966

EUCOM Theater- 011-49-6371-47-2264 DSN 314-480-2264 or 2235

Ramstein Air Force or 2235

Base, Germany

PACOM (Hickam AFB 808-448-8734 DSN 448-8734

Hawaii)

ο To ensure optimum care, communicate with the accepting

physician, and provide diagnosis, care rendered, and

subsequent medical care plan (next 24–48 h).

ο Ensure the patient has adequate quantities of supplies and

medications for duration of transfer (at least 72 h).

 Local Flight Surgeon Responsibilities.

ο Authority for determining whether patients are physiologically ready for air transport.

ο Resource for AE system information, communication, and

coordination.
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Emergency War Surgery

AE Process

Activity Location at Which the Activity Occurs

Request for AE mission (see Originating physician.

end of chapter for format).

Validation for Aeromedical PMRC (establishes AE requirement).

Evacuation.

Clearance to move by air. MTF (referring physician and local FS).

 Request versus Requirement. AE requests and patient

movement requirements are different. Physicians at

originating MTFs submit requests for movement, timing,

destination, suggested support therapies, and so forth. Only

the validating Flight Surgeon (usually located at PMRC; not

the local FS) and the PMRC can validate those requests, which

then become AE requirements.

 Validation versus Clearance for USAF AE.

ο Aeromedical evacuation clearance is a medical care event;

validation is a logistical event.

ο Clearance is a decision between the referring physician

and the local FS, addressing

♦ Description of the medical condition of the patient.

♦ Probability that patient can survive transit through an

aviation environment.

♦ What the patient needs to make the trip safely.

♦ Enroute medical capability requirements.

 Key Steps for USAF AE Patient Request.

ο Contact local FS and AE liaison for clearance consultation.

ο Determine the patient’s AE category, based on diagnosis

and ability to self-help in an emergency during flight.

ο Determine need for CCATT (see below). The CCATT adds

an additional level of support to the AE system for

movement of stabilized patients who require a higher level

of medical therapy or have the potential to experience

significant deterioration during movement. The CCATT

physician is the clinical authority and, with the other team

members, is responsible for documenting and providing
4.9

Aeromedical Evacuation

care. CCATT members may be called on to consult and/

or assist in the care of other patients.

ο A four-person burn transport team can augment a CCATT

team as required for inhalation injury and/or severe burns.

ο Determine if special requirements exist for transport; eg,

CAR, and splinting.

ο Determine patient movement items (PMI) required (eg,

ventilators, pulse oximeters, among others). Flight surgeon

must verify that all items accompanying the patient are

cleared for in-flight use.

ο Determine the patient’s movement precedence.

ο Submit request.

Critical Care Air Transport Teams

Intensivist physician.

 Capable of providing short term life-support, including advanced

airway management, ventilator management, and limited invasive

(nonoperative) procedures.

 Trained in critical care medicine, anesthesiology, or emergency

medicine.

Critical care or emergency medicine nurse.

 Experienced in managing patients requiring mechanical ventilation,

invasive monitoring, and hemodynamic support.

Cardiopulmonary technician.

 Experienced in management of patients requiring mechanical

ventilation, and invasive monitoring.

 Experienced in troubleshooting ventilatory support and monitoring

systems.
4.10

Emergency War Surgery