Essentials

The barometric altitude of a passenger aircraft cabin varies between sea level and 2,100 metres depending on the type of aircraft and its actual flight altitude. The oxygen content of the cabin air is always 21%, but when the barometric altitude of the cabin increases, the alveolar oxygen partial pressure decreases and is equivalent to breathing at sea level oxygen in approximately 15% concentration.
The arterial oxygen partial pressure (pO₂) of a healthy individual at sea level is approximately 13 kPa, and at 2,100 m altitude is still about 8 kPa. Hypoxic symptoms appear only above 3000 m when the arterial oxygen partial pressure falls below 7 kPa. The respective haemoglobin oxygen saturation values are 98% at sea level, 92% at 2100 m and 87% at 3000 m.
The cabin air is re-circulated so that it is changed 6–12 times in an hour. The cabin air is very dry with relative humidity varying between 10% and 20% during the flight.
Cabin pressure changes cause pressure changes in closed body cavities unless the pressures can be equalised. The most common symptoms are caused by infective or allergic conditions of the middle air or sinus cavity.

Illnesses and conditions that restrict air travel

In all the below-mentioned conditions, the airline company or the tour operator must already be contacted when the flight is booked. In association with this, the MEDIF form (Standard Medical Information Form for Air Travel http://www.finnair.com/go/documents/medif-form-en.pdf) is filled in.
- Recent myocardial infarction
- Recent cerebrovascular disorders
- Recent injuries
- Recent surgical operations
- Symptomatic coronary artery disease
- Chronic pulmonary diseases
- Conditions requiring oxygen therapy
- Psychoses
- Contagious diseases (tuberculosis, diphtheria)
- Anaemia (Hb < 75 g/l)
- Chickenpox in the vesicular phase due to risk of contagion; in the dry crusted phase, air travel is allowed.
The aircraft crew has not the possibility to deliver special assistance to individual passengers as they are responsible for the safety of the whole cabin. The crew is trained to deliver first aid but they are not authorized to give injections or otherwise administer drugs. Moreover, they cannot take the passengers’ medications for safekeeping during the flight.

A patient with pulmonary disease and flying

Severe COPD (forced expiratory volume in one second, FEV1 below 30% of reference value) and any pulmonary disease forming cavities entail the highest risk.
If oxygen saturation at rest is over 95 %, there is usually no need for supplemental oxygen.
- If supplemental oxygen is needed, in most cases 2 l/min is a sufficient flow.
- Supplemental oxygen may be available by the airline, or with a portable oxygen concentrator.
When a pneumothorax has been diagnosed prior to flight, its healing must be confirmed by chest x-ray. After this, airline companies recommend a 2-week waiting time before flying.
A patient with fresh infectious tuberculosis must not travel by flight. In infectious tuberculosis sensitive to conventional drugs, the treatment should continue for at least 2 weeks and sputum specimens must be negative before flying.
Regular respiratory infections do not prevent flying.
Sleep apnoea does not prevent flying. It is advisable that patients with CPAP therapy for sleep apnoea use the device also when sleeping during the flight.

Other illnesses and conditions requiring precautions

Mild angina pectoris
- If the patient is able to walk on level ground for 100 metres or climb stairs, he/she is fit to travel by air.
Acute psychosis
- Prenotification when booking the flight and an escort are always required.
Diabetes
- Possible special meals must be ordered in advance in association with the booking of the flight. A patient on insulin shall pack the syringes, needles and drugs in the hand luggage. The scheduling of the meals and medications during long flights should be discussed with the doctor who is in overall charge of the patient. See Multiple injection regime and travel across time zones in the article Insulin treatment of type 1 diabetes (Insulin treatment of type 1 diabetes).
Trauma patients
- A patient with a limb plaster may not be able to fit into an aircraft seat; during take-off and landing the patient must be able to maintain a normal sitting posture with the seat in an upright position and the safety belt fastened. The limb must not extend into the corridor of the aircraft. Stretcher transportation may be required.
Operated otosclerosis
- Avoidance of flying is recommended for 2 to 4 postoperative weeks.
Pregnancy
- During the last month of pregnancy the mother should not fly, i.e., air travel is allowed until 36 weeks of pregnancy are reached.
- Air travel on shorter and domestic routes is allowed until the end of the 38th week, provided that the pregnancy has proceeded normally and there are no pregnancy complications or signs of initiation of labour.
- After 28 weeks of pregnancy, a medical certificate may be required to prove that the pregnancy has proceeded normally. Requirements vary between different airline companies. More detailed information is available on the websites of airline companies and from tour operators.
- A healthy newborn may travel without restrictions on all flight routes from the age of 2 days onwards.

First aid

For the treatment of in-flight acute illnesses there are medical oxygen, first aid equipment, physician’s equipment, equipment for intravenous fluid therapy and protective equipment for infectious diseases available.
In the aircrafts of most airlines operating in Europe, there is also a defibrillator. The cabin crew, however, is not necessarily trained to use it.

Circulatory problems during long-haul flights

Prolonged sitting increases the amount of fluid accumulated in the lower extremities which leads to leg swelling.
Immobility may increase the risk of venous thrombosis in the lower extremities; therefore, it is recommended to do leg exercises or to walk along the cabin corridor every 1 to 2 hours, the conditions allowing. The passengers should get acquainted with the exercise instructions.

Ear symptoms

The narrow Eustachian tube connects the middle ear cavity with the nasopharynx and further with the outside air. During the flight, the function of the Eustachian tube may be disturbed due to e.g. common cold or allergy. This impedes pressure balancing between the outside air and the middle ear. This leads to ear pain; even otitis media is possible (Barotitis and barotrauma).
- Use of compression stockings during longer, over 5-hour flights reduces swelling and the risk of venous thrombosis [Evidence Level: A].
See also Prevention of venous thromboembolism (Prevention of venous thromboembolism).

Aircraft first aid equipment

The contents may vary depending on the airline company and the aircraft type.

Table 1. Contents of the First Aid Kit (FAK) and the Emergency Medical Kit (EMK) in aircrafts

First Aid Kit (FAK)	Emergency Medical Kit (EMK)
Bandages Burn dressings Large and small wound dressings Adhesive tape, safety pins, scissors Adhesive dressings Antiseptic wound cleaner Adhesive wound closures Resuscitation mask (disposable) Analgesic Antiemetic Nasal decongestant spray/drops Bronchodilator (inhalable) Antacid Antidiarrhoeal First-aid handbook Ground/air visual signal code book Disposable gloves Dustbin bag Incident reporting form	Blood pressure meter Stethoscope Syringes and needles Tracheal tube Tourniquet Disposable gloves Needle disposal box Urinary catheters and anaesthetic gel Delivery assistance equipment Oxygen masks and resuscitation bag Coronary vasodilator Antipasmodic (injectable) Adrenaline 1:1000 and 1:10,000 (injectable) Corticosteroid (injectable) Strong analgesic (injectable) Diuretic (injectable) Antihistamine (tablets and injectable) Sedative/antiepileptic (tablets and injectable/rectal) Medication for hypoglycaemia (injectable) Antiemetic (injectable) Atropine (injectable) Antiarrhythmic agent Bronchodilator (injectable and inhalable) List of the drugs with their indications and dosage instructions (native language/English)

Air travel and illness

Essentials

Illnesses and conditions that restrict air travel

A patient with pulmonary disease and flying

Other illnesses and conditions requiring precautions

First aid

Circulatory problems during long-haul flights

Ear symptoms

Aircraft first aid equipment