1. Assessing fitness to fly involves considering how the low pressure cabin environment may impact medical conditions. The reduced oxygen and dry air can affect the lungs and cardiovascular system. 2. For many stable cardiac and respiratory conditions, air travel is safe if supplemental oxygen is provided if needed. However, recent surgery, infections, or pneumothorax absolutely contraindicate air travel. 3. Diabetes and most stable hematological disorders usually do not restrict air travel if medications are properly managed for changing time zones. Pregnancy after 36 weeks or complications generally preclude air travel for safety.

1. Assessing fitness to fly
Guidelines for medical professionals from the Aviation Health Unit,
UK Civil Aviation Authority
Introduction be taken into consideration for those Table 1
Every year, over one billion people with cardiac, pulmonary conditions
Cardiovascular indications for
travel by air and that figure is or anaemia.
medical oxygen during
predicted to double in the next two
commercial airline flights
decades. Air travel is a comfortable The decrease in ambient pressure in
and safe means of transport and is the cabin, compared to ground l Use of oxygen at baseline
accessible to all sectors of the level, will cause any gas to expand altitude
population. The global increase in and increase in volume by l CHF NYHA class III - IV or
travel, as well as an increasingly approximately 30%, which may baseline PaO2 less than 70 mm
aged population, means that there cause problems if trapped in any Hg
will be a significant increase in older body cavity, e.g. the ear, giving rise l Angina CCS class III-IV
passengers and those with illness to pain and possible perforation of l Cyanotic congenital heart
who will wish to travel. the ear drum. Similar issues may disease
occur following surgery, if gas is l Primary pulmonary
Physiology of flight introduced to the abdominal cavity hypertension
An understanding of the physics or the eye. l Other cardiovascular diseases
and physiology of flying and how associated with known baseline
this may interact with pathology is Contrary to what is believed by hypoxaemia
useful in coming to an objective many, the aircraft cabin
conclusion about a passenger’s environment does not result in CHF - Congestive Heart Failure
fitness to fly. Contrary to popular dehydration, as there is no evidence NYHA - New York Heart
belief, modern aircraft are not of any change in osmolality. Association
pressurised to sea level equivalent, However, the cabin has a low CCS - Canadian Cardiovascular
and fly with a cabin altitude humidity, usually in the range of Society
between 5,000 and 8,000 feet. This 10% to 20% compared to that in
results in reduced barometric buildings, which is in the order of
pressure and a concomitant 40% to 50%. This is particularly increasing their ventilation and by
decrease in the partial pressure of noticeable in the mucous developing a mild tachycardia,
alveolar oxygen (PaO2). Few aircraft membranes, especially if wearing which may result in increased
fly for any significant period of time contact lenses and also in the skin. myocardial oxygen demand. In
at the upper limit of cabin altitude of patients with limited cardiac reserve,
8,000 feet, where the barometric Jet lag, or circadian dysrhythmia, in the use of supplemental oxygen
pressure is approximately 565 mm addition to being an annoyance for (Table 1) may be required and most
Hg with an alveolar partial pressure healthy travellers may complicate commercial airlines will supply this
of O2 of approximately 75mm Hg. the timing of medication, e.g. in when requested in advance
However, due to the shape of the diabetic passengers who are treated although a charge may be levied.
oxy-haemoglobin dissociation curve with insulin (see below). There is currently ongoing work,
(Figure 1), this only results in a fall of with the Department for Transport,
oxygen saturation to around 90%. On commercial flights, regardless of looking at the carriage of oxygen.
This fall is well tolerated by most aircraft type, many passengers sit in This may permit passengers to carry
healthy travellers and is smaller spaces than in the home their own oxygen, but the results of
compensated by the normal environment and may have reduced this work are not yet complete.
physiological response. However, opportunity to get up and walk
this decrease in saturation needs to about. The potential for the Despite the physiological changes
development of travellers’ that occur at altitude, the majority of
thrombosis (see below), particularly patients with cardiac conditions can
on long haul flights, should be travel safely as long as they are
borne in mind and the use of lower cautioned to carry their medications
limb exercises may be of value in in their hand baggage.
improving the venous return.
Angina Pectoris, if stable, is usually
Cardiovascular disease not a problem in flight.
Hypobaric hypoxia, i.e. that due to a Patients with a recent myocardial
lowered oxygen pressure at altitude, infarction may travel after 7 to 10
is an area of concern for travellers days if there are no complications. If
with cardiovascular disease. The the patient has undergone an
decrease in oxygen saturation may exercise test which shows no
have implications for passengers residual ischaemia or symptoms,
with cardiac disease who wish to this may be helpful, but is not a
Figure 1: oxygen dissociation curve of travel. Patients compensate to an mandatory requirement.
whole blood extent for this relative hypoxia by

2. Coronary artery bypass grafting and medically stable. Interaction with environment does not represent a
other chest or thoracic surgery airline electronics or aviation specific challenge to those suffering
should prove no intrinsic risk in the security devices is highly unlikely for from asthma that is stable. The key
aviation environment as long as the the most common bi-polar issue is to ensure that all medication
patient has fully recovered without configuration. is carried in hand baggage. It may
complications. However, as air is Following a cerebrovascular be prudent that patients with
transiently introduced into the accident, patients are advised to asthma, other than the mildest
thoracic cavity, there is a potential wait 10 days following an event, cases, should take a course of oral
risk for barotrauma due to the although if stable, may be carried steroids with them, in order that
gaseous expansion which occurs at after 3 days. For those with cerebral they could intervene early if there is
altitude. It is therefore prudent that arterial insufficiency, supplementary any deterioration in their condition.
patients should wait until the air is oxygen may be advisable to prevent
reabsorbed, approximately 10 to 14 hypoxia. Chronic Obstructive Pulmonary
days before travelling by air. Disease (COPD)
Clinical judgement has an important Patients with chronic bronchitis and
Patients with uncomplicated role in the individual assessment of emphysema are susceptible to in-
percutaneous coronary fitness to fly. However, some flight hypoxaemia, depending on
interventions such as angioplasty cardiovascular contraindications to their baseline PaO2. The walking
with stent placement may be fit to flight are shown in Table 2. test and/or hypoxic challenge may
travel after 5 days, but should be be appropriate and medical oxygen
medically stable, and individual Respiratory disease can be provided by the airline with
assessment is essential. Medical advice to those with prior notification. A fee may be
respiratory disease on fitness to fly levied for this. Flow rates of 2 or 4
depends primarily on: litres per minute are usually
Table 2
available, but generally it is not
Cardiovascular
a) the type, reversibility and permissible for passengers to carry
contraindications to
functional severity of the underlying their own oxygen on board, as the
commercial airline flight
respiratory disease equipment must meet specific
aviation regulatory standards.
l Uncomplicated myocardial b) an assessment of the likely Particularly, there are issues
infarction within 7 days tolerance to the cabin altitude and concerning the permissible water
l Complicated myocardial ambient oxygen concentration. content to prevent freezing and the
infarction within 4-6 weeks type of valve, which must be able to
l Unstable angina In patients with significant disease, cope with varying cabin pressures.
l Decompensated congestive the relative hypoxia encountered in
heart failure the aircraft cabin may be easily Bronchiectasis and Cystic Fibrosis
l Coronary artery bypass graft correctable by therapeutic oxygen. Control of lung infection and
within 10 days The partial pressure of oxygen in measures designed to loosen and
l Cerebrovascular accident the cabin at normal cruising altitude clear secretions are important
within 3 days is considered to be equivalent to an aspects of medical care, both on the
l Uncontrolled cardiac oxygen concentration of ground and during travel.
arrhythmia approximately 17% at sea level. Appropriate antibiotic therapy,
l Severe symptomatic valvular Some respiratory physicians can adequate hydration and medical
heart disease carry out assessments in a oxygen may be required for both
laboratory using oxygen-nitrogen conditions. Medication to decrease
mixes to simulate this cabin sputum viscosity is helpful e.g.
environment. This is termed a deoxyribonuclease in the low
Symptomatic valvular heart disease ‘hypoxic challenge’. If it results in a humidity of the aircraft cabin.
is a relative contraindication to PaO2 less than 55 mm of mercury,
airline travel. Individual assessment medical oxygen is indicated. Respiratory infection
by the treating physician is essential, Patients with active or contagious
paying particular attention to the Guidelines on this approach to infection are unsuitable for travel
functional status, severity of assessment can be found at the until there is documented control of
symptoms and left ventricular British Thoracic Society website at the infection and they are no longer
function, in addition to the presence www.brit-thoracic.org.uk. infectious. Those recovering from
or absence of pulmonary acute bacterial infection e.g.
hypertension. There is no However, the single and most pneumonia should be clinically
contraindication to air travel for practical fitness to fly test, is to improved with no residual infection
patients with treated hypertension, assess whether the patient can walk and satisfactory exercise tolerance
as long as it is under satisfactory 50 yards/metres at a normal pace or before flying. Patients with
control and the patient is reminded climb one flight of stairs without respiratory viral infections e.g.
to carry their medication with them severe dyspnoea. If this can be influenza, may infect those sitting
on the flight. accomplished, it is likely that the adjacent to them and they should
patient will tolerate the normal postpone air travel until the infection
Those with pacemakers and aircraft environment. has resolved.
implantable cardioverter
defibrillators may travel without Asthma Pneumothorax
problems by air once they are The normal aircraft cabin The presence of a pneumothorax is

3. an absolute contraindication to air than they have been in the past. It is insulin is not packed in the hold
travel as trapped air may expand not uncommon to see young baggage even if it is not being used
and result in a tension patients with haemoglobins of the during the flight as insulin in the
pneumothorax. In general, it should order of 7 g/dl and elderly patients hold may be exposed to
be safe to travel approximately 2 with haemoglobins of temperatures that could degrade it
weeks after successful drainage of a approximately 8 g/dl (see and there is the potential risk of loss
pneumothorax with full expansion Haematological Disorders). of baggage en-route. Insulin may be
of the lung. If there is a need to satisfactorily carried in a cool bag for
travel earlier, safe travel is possible It is important to remember that even the longest sector. Individual
using a one-way Heimlich valve intestinal gas will expand by regimes should be discussed with
attached to the chest drain. approximately 30% by volume at a the diabetic management team, but
cabin altitude of 8,000 feet. Many some general guidelines may be
Pregnancy post-abdominal surgery patients helpful.
The advisability of flying whilst have a relative ileus for some days,
pregnant is a frequently asked thereby putting them at risk of When travelling east, the day will be
question. The commercial aircraft tearing suture lines, bleeding or shortened and if more than two
environment is not generally indeed, in extreme circumstances hours are lost, it may be necessary
considered hazardous to a normal perforation. Stretching intestinal or to take fewer units with intermediate
pregnancy. At a normal cabin gastric mucosa may also result in or long-acting insulin. When
altitude the maternal haemoglobin haemorrhage. To avoid such travelling west, the travel day will be
remains 90% saturated and because complications, travel should be extended and if this is more than 2
of the favourable properties of foetal avoided for 10 days following hours it may be necessary to
haemoglobin (HbF) including abdominal surgery. Following other supplement this with additional
increased oxygen carrying potential procedures, such as colonoscopy injections of short-acting insulin or
together with a high foetal where a large amount of gas has an increased dose of intermediate-
haematocrit and the Bohr effect, been introduced into the colon, it is acting insulin. Type 2 diabetes is not
foetal PaO2 changes very little. The advisable to avoid travel by air for a problem on diet or oral
key focus in assessment of fitness to 24 hours. Similarly, it is advisable to medication, nor indeed on insulin as
fly is the health and wellbeing of the avoid flying for approximately 24 the endogenous insulin, which
mother and the baby. Delivery in hours after laparoscopic remains in Type 2 diabetes will
flight, or diversion in flight to a intervention, due to the residual CO2 provide a suitable buffer and assist
location that may not have high gas, which may be in the intra- control. Further information on
quality obstetric services, is abdominal cavity. diabetes and travel is available from
undesirable. For this reason, most the Diabetes UK website
airlines do not allow travel after 36 Neurosurgical intervention may (www.diabetes.org.uk).
weeks for a single pregnancy and leave gas trapped within the skull,
after 32 weeks for a multiple which again may expand at altitude. Haematological disorders
pregnancy. Most airlines require a It is therefore advisable to avoid air Patients with a haemoglobin of
certificate after 28 weeks confirming travel for approximately 7 days greater than 8 g/dl may travel
that the pregnancy is progressing following this type of procedure. without problems assuming there is
normally, that there are no no coexisting condition such as
complications and the expected date Ophthalmological procedures for cardiovascular or respiratory
of delivery. In specific individual retinal detachment also involve the disease. If the haemoglobin is less
circumstances, an airline may allow introduction of gas by intra-ocular than 7.5 g/dl, special assessment
some discretion. injections, which temporarily should be made and the use of
increase intra-ocular pressure. supplemental oxygen should be
Surgical conditions Depending on the gas, it may be considered.
The issue of air travel following necessary to delay travel for
surgical intervention is becoming an approximately 2 weeks if sulphur Individuals with chronic renal
increasingly important issue with hexafluoride is used and for 6 weeks insufficiency or other medical
the wider use of day surgery. It with the use of perfluoropropane. condition predisposing to anaemia,
should be borne in mind that post- For other intra-ocular procedures which is chronic in nature, will
operative patients are in a state of and penetrating eye injuries, 1 week usually tolerate a lower
increased oxygen consumption due should elapse before flying. haemoglobin level than if the
to the trauma of surgery, the anaemia is of acute onset. Sickle cell
increased adrenergic outflow and Diabetes trait does not present a particular
the possible presence of sepsis. Air travel should not pose significant problem at normal cruising altitude.
Concurrently, oxygen levels may be problems for patients with well- However, patients with sickle cell
decreased or fixed in patients who controlled diabetes. Pre-planning is anaemia should travel with
are elderly, volume depleted, supplemental oxygen and should
important and discussion of the
anaemic or who have defer travel for approximately 10
itinerary with the diabetic
cardiopulmonary disease. days following a sickling crisis.
management team plays an
Consequently, for such patients it
important part in preparation for
would be wise to delay air travel for Trauma/orthopaedics
several days or request oxygen to travel. It is essential that the diabetic Following the application of a
be provided. With the decreased use passenger carries adequate plaster cast, the majority of airlines
of blood transfusion, many post- equipment and medication in their restrict flying for 24 hours on flights
operative patients are more anaemic hand baggage. It is important that of less than 2 hours or 48 hours for

4. longer flights. This is due to the fact “economy class syndrome”. There have medical advisors who provide
that air may be trapped beneath the is no evidence that the cabin advice and ’clear‘ passengers as fit
cast. If there is an urgent need for environment activates the to fly. The key information that they
travel before these limits, the plaster coagulation system of normal require is the nature of the
cast may be bi-valved. If a individuals. The absolute risk, as individual’s condition, its
pneumatic splint is used, some air shown in the WRIGHT Study, was 1 severity/stability, medication being
should be released to allow for in 4656 flights of more than 4 hours taken and any pertinent information
gaseous expansion at altitude, duration. The risk factors for about mobility. The clearance can be
which could cause discomfort as thrombosis are well known and are done by telephone or by formal
well as potential circulatory listed in Table 3. communication using the Med IF
compromise or neuropraxia. form available through travel agents
Prophylactic measures should be or from the Internet which allows
Psychiatric Conditions undertaken according to the degree the medical information to be
The key consideration in this area is of risk. Simple, effective measures structured in a manner that can be
identical to other medical are to move about the aircraft cabin processed by the majority of
conditions, i.e. will the condition and to carry out the lower limb airlines.
interfere with the safe conduct of the exercises shown in airline videos
flight? or will the flight environment and in-flight magazines. Any The final decision whether or not to
exacerbate the condition? With the specialised prophylaxis should be carry a passenger is that of the
modern management of many targeted at those at highest risk and airline, but the more information
psychiatric conditions, air travel include properly fitted anti- that is provided in advance, the
should not be a problem for the embolism stockings giving more likely it is that a fair, evidence-
majority of individuals. It is graduated compression to the limb, based decision can be made.
essential however, that the condition subcutaneous low molecular weight
is stable and if medication is heparin, which is highly effective Useful sources of
required it is taken regularly. The and has a low risk of bleeding and information
main areas for concern are those in extremely high risk cases, oral Aviation Health Unit
whose behaviour may be anticoagulation. It is important to www.caa.co.uk/aviationhealthunit
unpredictable, aggressive, emphasise that the risk of side
disorganised or disruptive. In these effects from the use of aspirin Aerospace Medical Association
circumstances, air travel would be outweigh any potential anti- www.asma.org/pdf/publications/m
contra-indicated. Patients with well- thrombotic effect and its use is not edguid.pdf
managed psychotic conditions may recommended.
require an escort to ensure regular British Airways
medication and to assist in case of www.britishairways.com/health/do
Table 3
problems. The escort may be a cs/before/airtravel_guide.pdf
Risk factors for DVT
reliable companion or in more
l Thrombophilia enhancing
difficult cases, a qualified health MEDIF Form
clotting activity
professional. Taking a careful history www.britishairways.com/cms/glob
eliciting especially details of l Recent major surgery al/assets/pdf/BA_Medif_123.pdf
previous disturbed or disorientated l Trauma or surgery of the
behaviour is particularly important. lower limbs British Medical Association
Close liaison with the treating l Family history of deep vein www.bma.org.uk/ap.nsf/Attachme
physician and the airline concerned thrombosis ntsByTitle/PDFFlying/$FILE/Impacto
is important and clearance to travel l Age > 40 years fflying.pdf
can be done by either telephone or l The oral contraceptive pill
by the formal Med IF form, details of Aviation Health Unit
which are given later in this
document. The UK Civil Aviation Authority’s
General issues Aviation Health Unit (AHU) was
DVT It is important to note that although formed on 1 December 2003 to
Deep vein thrombosis is not cabin crew are trained to render advise Government on
intrinsically dangerous but the advanced first aid, they are not passenger and aircrew health
complications of pulmonary trained to administer medication. In issues. In March 2007 the AHU
embolism can be life threatening. It addition, most airlines will assist was given an additional statutory
has been shown that DVT can occur passengers to reach the toilet function in safeguarding the
in many other forms of travel, as accommodation on the aircraft but health of all persons on board
described by Homans in 1954. The cannot render more personal aircraft. The recent House of
World Health Organisation Research hygiene or nursing care. Lords Inquiry (Air Travel and
Into Global Hazards of Travel
Health: an Update) emphasised
(WRIGHT) Project recently reported The majority of in-flight
the pivotal role of the Unit as a
that the key determinant for deep emergencies occur to individuals
focus for those interested in
venous thrombosis is whose medical condition is
immobilisation and the risk of unknown to the airline and it is aviation health matters. The AHU
thrombosis is increased by travel of therefore essential that the can be contacted on 01293
greater than 4 hours. Thus passenger’s physician sends 573674 or by email:
“travellers’ thrombosis” is the most adequate details well in advance of aviationhealthunit@caa.co.uk
appropriate term to use, rather than the flight to the carrier. Most airlines