**7.2 Medical Criteria for Transportation of Patients by Air
Ambulance:**

General considerations/requirements

Specific considerations/requirements for emergency medical evacuation

Specific considerations/requirements for elective medical transport

Logistical aspects, pros and cons

Follow-up procedures

This chapter will provide you with a basic understanding of the
parameters for transporting patients by air. Commercial carriers are
able to safely transport passengers with medical problems of many kinds.
Those with stable disabilities are entitled to access. Patients with
unstable problems must be evaluated before flying and commercial
transport may not be appropriate. Air ambulance services are available
to move patients from accident sites to definitive care and to transport
unstable and those too ill to travel by commercial aviation. You will be
able to assess a patient for flight by applying your basic knowledge of
human pathology and physiology to the environmental conditions of air
travel. This section integrates the previous lesson on commercial air
travel with air ambulance service.

**Medical Criteria for Transportation of Patients by Air Ambulance**

Many airline passengers are not medically normal. However the same
abnormal flight environment necessitating periodic medical evaluation of
pilots is experienced by these passengers including lower barometric
pressure, oxygen levels, humidity and variations in acceleration forces.
You must apply your basic knowledge of aviation to the evaluation of
patients who are potential passengers.

Passengers with known medical conditions and disabilities are covered
under the Americans with Disabilities Act and the Air Carrier Access
Act. These federal laws require commercial carriers to provide transport
to those people with disabilities whose condition does not represent a
threat to the health and safety of themselves or others. For example,
paraplegics must be provided with seating on a commercial airliner and
their wheelchair or transportation device carried at no extra charge.
Paraplegics who have good upper body strength prefer aisle seating and
can often transfer themselves from the special aircraft aisle wheelchair
to the seat. Quadriplegics will prefer cabin wall seating as providing
more support on one side. Bulkhead seating also provides more room for
transfers. Seating can be specially requested and like all
accommodations, should be done at least 48 hours before scheduled
travel. Failure to provide 48 hours advance time may prevent the airline
from accommodating a request, particularly in regards to oxygen. These
levels have forced airlines and airports to make numerous changes to
their facilities in order to accommodate the needs of the disabled.
Spillable batteries from powered wheelchairs, normally considered to be
unacceptable hazardous cargo, become a waivered item requiring special
handling.

Boarding and deplaning of disabled passengers will require additional
assistance from company personnel. The passenger who has communication
problems, for example those visually impaired, may need a special
briefing separate from the standard safety briefing given before
takeoff. On the other hand, most disabled passengers are prohibited from
sitting in emergency exit seats if they cannot fully and uninhibitedly
participate. The decision is not the option of the passenger but belongs
to the flight crew.

The Air Carrier Access Act applies only to U. S. national airlines, not
foreign air carriers. A disabled passenger switching to a foreign
carrier may not receive accommodations unless a "Code Share" agreement
is in place. This is a commercial agreement between carriers where a
single flight may have multiple flight designations. That is the
airplane itself may be operated by one airline while simultaneously
carrying the passengers ticketed as if they were on another airline.
Several of the major U.S. carriers participate in these agreements and
the Air Carrier Access Act would then apply.

Patients wishing to travel with stable medical conditions should be
evaluated medically. They should be cautioned to carry any medications
on their person and in labeled containers. Some conditions, such as
asthma, may become unstable in flight if the patient is non-compliant
with their treatment.

Recent medical conditions should be evaluated carefully. Myocardial
infarctions should be stable for 10 to 20 days prior to commercial
travel. Unstable cardiac conditions must wait much longer, usually on
the order of 6 weeks. Angioplasty should typically wait 2 weeks. Post
operative patients should not travel until all internal gas is absorbed.
Stroke patients should delay two weeks and be stable. No intracerebral
or intraocular gas can be permitted, even small amounts, as the bubble
expansion can be lethal.

Obstetrical patients can travel safely up to 32 weeks in an
uncomplicated pregnancy and up to 36 weeks if evaluated and stable.
Neonates are usually safe to travel after the first week of life. No one
should travel if there is an active infection of the sinuses or airways.

Pulmonary patients may need supplemental oxygen to travel. While the
mild hypoxia of flight is generally well tolerated, those who need
supplemental oxygen while at rest or with minimal exertion, such as
walking 50 feet or climbing a flight of stairs, should also receive a
prescription for supplemental oxygen during travel. During flight, most
carriers can provide oxygen but will not provide it on the ground during
transfers between flights or at the arrival airport, necessitating other
arrangements need to be made.

Psychiatric patients need to be stable and non-violent. Compliance with
their medication is important and a traveling companion may be a
consideration. Those with neurodegenerative diseases such as Alzheimer's
may become disoriented with air travel, manifesting "Sundowner
Syndrome".

Diabetics will need to adjust their insulin due to time zone shifts. For
eastbound passengers of more than 6 time zones, give the usual dose on
the morning of departure. The next morning give 2/3 the regular dose and
10 hours later test the glucose level, administering another 1/3 of the
regular dose if elevated.

Westbound passengers crossing more than six time zones should take their
regular dose on the day of departure and 18 hours later take 1/3 their
morning dose. Check their glucose regularly and snack if low. They may
resume the regular schedule the next day.

Commercial airlines can provide only limited in-flight medical
assistance. Only one US carrier permits patients on stretchers
(Northwest). Cabin pressure cannot be changed just to accommodate a
passenger as this seriously impacts aircraft operations, limiting
altitude, speed and range. Oxygen may be provided on some, but not all,
airlines and only with a medical prescription. Oxygen is limited to a
maximum flow rate of 8 liters per minute. Patients' requiring flows in
excess of this cannot travel commercially. Other medical equipment, such
as intravenous lines, respirators and special monitors are usually not
permitted on commercial aircraft due to electrical and safety
considerations. Individuals, who are medically unstable or with active
communicable diseases, cannot be permitted to travel as they represent
unacceptable risks to the health and safety of themselves and others.
Some patients need urgent rescue and transportation for definite care.
Such travelers should be moved by air ambulances. For additional
information, refer to Section 7.1.

Air medical transport falls into two categories. The first is emergency
air rescue and recovery. In such cases, governmental agencies operate
air ambulances first aid on scene, to extract and recover patients and
transport them to definitive medical care. Other forms of air ambulance
are for transporting patients between hospitals for continuation of
specialized medical care, or in other cases, transport of patients over
long distances who are too ill or unstable to travel by commercial
airliner. Of the former, most are helicopter services, of the latter, a
mixture between helicopter and fixed-wing operations.

![](media/image1.jpeg){width="2.6041666666666665in"
height="2.1145833333333335in"}Loading a patient into an air ambulance

The medical care required during flight is significantly different from
care in a hospital or during ground transportation by ambulances.
Hypoxia is always a consideration, with the addition of noise,
vibration, limited physical space and motion of the aircraft. Special
concerns exist for medical containers, such as glass bottles, or
anything that may be pressurized and can, therefore, rupture in flight.
Both passengers and medical crew must be restrained in flight to avoid
injury and if passengers have certain traction devices provided on the
ground using weights, these must be replaced with spring-type devices.

![](media/image2.wmf){width="4.977083333333334in" height="3.74375in"}

In-flight intubated patient

Certain in-flight medical treatment cannot be provided in flight,
including dialysis and cardiac balloon support. Infusion devices should
be automated and designed not to be dependent upon gravitational flows.
Electrical equipment for aircraft should be battery driven and
self-sustained, as most helicopters and fixed-wing aircraft are not
equipped with standard 110-volt/60-cycle electrical outlets. Medical
equipment is usually customized for each particular kind of mission, and
may include oxygen supplies and pulmonary equipment, specific pediatric
devices and incubators, specialized monitors and counter-pressure
devices.

The most critical device, which should be included on all flights, is a
pulse/oxygen monitor. Typical medical devices, such as a stethoscope,
function very poorly in the aircraft environment due to background noise
and vibration. Doppler devices and automated blood pressure monitors are
far superior, but still have technical limitations, even under the most
benign circumstances. Other special monitors for fetal, cardiac or
vascular status can be added to a flight as required.

The advantage of air ambulance transportation is that the cabin
pressures may be controlled and limited much more closely than on a
commercial aircraft, which will typically operate at the equivalent of
7,000-8,000 feet (barometric pressure of \~550 mmHg), although limiting
the cabin altitude to 1,000 or 2,000 feet, or even to the altitude of
the departure airport can seriously limit the range of most air
ambulances with pressurized cabins, sometimes reducing the operating
range by 50%, because the aircraft can no longer climb to its fuel
efficient cruise altitude. Certain conditions, such as transporting
decompression sickness patients to centers for hyperbaric treatment
mandate cabin pressure limits.

The primary accrediting body for air ambulance is the Commission on
Accreditation of Medical Transportation Systems, which has recommended
guidelines for basic life support; advanced life support and special
medical care needs. Recommendations for appropriate training of medical
personnel assigned to the aircraft, which is far above the routine
emergency and ambulance personnel, are also available. This includes not
only the understanding of the aircraft environment and the special
physiologic conditions, but also operating procedures for the aircraft
and safe on-loading and off-loading of patients, and emergency
procedures. Emergency medical personnel must be trained, certified and
licensed in accordance with their local governmental agencies. Specific
research is conducted by the Foundation for Air Medical Research under
the aegis of the Association of Air Medical Services.

Special considerations must be made for the decision to use air
ambulance services. The first consideration is whether the flight is
safe or not. If weather conditions or the condition of the aircraft
itself is unsafe, then ground transportation should be used. The final
decision for committing an aircraft to fly should be the pilot's -- not
the doctor or any other medical personnel. Failure to assign the full
responsibility and authority to the pilot resulted in a series of
aircraft accidents in the late 1980's, when doctors overrode pilots and
ordered them to fly into dangerous weather conditions, or take off in an
unsafe aircraft. These accidents were the impetus behind the creation of
the Association of Air Medical Services.

![](media/image3.png){width="4.145833333333333in"
height="2.8958333333333335in"} Road Landing at Accident Site

A second consideration is whether the timing is appropriate. Use of an
air ambulance helicopter to transport a patient from one hospital to
another hospital within the city may result in only a minimal time
saving and in some cases prolongation of the transport time and
considerable increase in cost. In effect, if the flight is of less than
an hour's duration there is probably no advantage to using an aircraft
over surface transport. On the other hand, poor ground accessibility or
unsafe roads can make air travel advantageous.

The Air Traffic Control system will afford priority routing to all air
ambulance flights. A special call sign, LIFEGUARD, is assigned to
missions of an urgent medical nature and to be utilized only for that
portion of the flight requiring expeditious handling. Similarly AIR EVAC
and MED EVAC call signs are used by urgent military medical missions in
the United States. Air Traffic Controllers will in effect provide
"lights and sirens" for an aircraft using these call signs and clear
away all conflicting traffic.

The third consideration is experience and equipment of the transport.
Air ambulances and helicopters are limited in what equipment they can
carry, but almost uniformly the equipment is better and the personnel
are more experienced than ground units. This is due to the costs of
operation and higher pay for flight personnel, resulting in additional
incentives for state-of-the-art training and equipment.

The most important question is whether the patient is so sick that
ground or commercial transport is not appropriate? Certainly any patient
who is unstable, or whose medical condition represents a threat to the
health and safety of others should not travel by commercial aviation.

Logistical concerns are essential. Particularly, helicopters require
specialized landing zones that are appropriately lit and free of
obstacles, and must have controlled access so that spectators do not
wander up towards a helicopter sitting on the ground. There have been
cases where individuals have walked through the tail rotor, with fatal
outcome. Cost and competition among air ambulance services is a
double-edged sword, sometimes providing economic savings but in other
cases may result in unsafe cost cutting maneuvers.

References:

Boyd, C.R., Air versus ground transportation, *Journal of Trauma*, 1989,
29:789-94.

[Medical Guidelines for Airline Travel]{.underline}, Air Transport
Committee of the Aerospace Medical Association, Alexandria VA, 1997

Parmet, A.J., [Aviation Medicine]{.underline}, "Clinics in Occupational
and Environmental Medicine", 2000, Vol II, pp81-91, 2002

Rayman, R.B. & Williams, K.A., "The Passenger and Patient in Flight"

[Fundamentals of Aerospace Medicine]{.underline}, 3^rd^ Edition,
pp453-469, 2002