Appropriate planning reduces the risks associated with travel, including air travel. Prior to travel, patients and their medical providers should review planned itineraries and relevant medical histories, required vaccinations Vaccinations Appropriate planning reduces the risks associated with travel, including foreign travel. Prior to travel, patients and their medical providers should review planned itineraries and relevant... read more , prophylactic measures against infections such as malaria Malaria Appropriate planning reduces the risks associated with travel, including foreign travel. Prior to travel, patients and their medical providers should review planned itineraries and relevant... read more and traveler's diarrhea Traveler’s diarrhea Appropriate planning reduces the risks associated with travel, including foreign travel. Prior to travel, patients and their medical providers should review planned itineraries and relevant... read more , and advice about personal protection measures, including those related to noninfectious threats. For older travelers, the most common causes of death are heart attack and stroke; for other travelers, the most common cause of death is road traffic crashes.
Air travel can cause or worsen certain medical problems; some are considered a contraindication to flight (see table Contraindications to Flying Contraindications to Flying Appropriate planning reduces the risks associated with travel, including air travel. Prior to travel, patients and their medical providers should review planned itineraries and relevant medical... read more ), and others may cause discomfort. Serious complications are rare, and a few simple precautions can reduce some of the more common issues.
During a flight, any health care practitioner among the passengers may be asked to help fellow passengers who become ill. Additionally, most commercial aircraft carry first-aid equipment, including an automatic external cardioverter defibrillator and limited medical supplies. Airline personnel are receiving more first-aid training now than in the past. Although physicians aiding ill or injured passengers are usually protected from litigation by the Good Samaritan concept, they should avoid practicing beyond their training or expertise.
Further information about air travel may be obtained from the medical department of major airlines, the Federal Aviation Administration (www.faa.gov), online travel information sources, or local travel clinics.
Barometric pressure changes
Commercial airplanes and jet aircraft are pressurized only to the equivalent of an altitude of 6000 to 8000 ft (1830 to 2440 m), not to sea level pressure. Thus, air in body cavities or other closed spaces expands by about 25%; this expansion may aggravate certain medical conditions.
Untreated dental problems or recent dental procedures may become painful when air pressure changes. People with upper respiratory inflammation or allergic rhinitis may develop obstructed eustachian tubes (which may cause barotitis media Otic Barotrauma Otic barotrauma is ear pain or damage to the tympanic membrane caused by rapid changes in pressure. To maintain equal pressure on both sides of the tympanic membrane (TM), gas must move freely... read more ) or obstructed sinus ostia (which may cause barosinusitis Ear and Sinus Barotrauma Barotrauma is tissue injury caused by a pressure-related change in body compartment gas volume. It can affect the ear (causing ear pain, hearing loss, and/or vestibular symptoms) or the sinuses... read more ). Frequent yawning or closed-nose swallowing during descent, use of decongestant nasal sprays, or use of antihistamines before or during flight often prevents or relieves these conditions. Some people suck on hard candies during descent.
Air travel is contraindicated for patients who have or are likely to develop pneumothorax Pneumothorax Pneumothorax is air in the pleural space causing partial or complete lung collapse. Pneumothorax can occur spontaneously or result from trauma or medical procedures. Diagnosis is based on clinical... read more (eg, those who have large pulmonary blebs or cavities) and for those in whom air or gas is trapped (eg, those who have an incarcerated bowel Hernias of the Abdominal Wall A hernia of the abdominal wall is a protrusion of the abdominal contents through an acquired or congenital area of weakness or defect in the wall. Many hernias are asymptomatic, but some become... read more , those traveling 10 days after chest or abdominal surgery, those who have intraocular gas injection) because even modest expansion may cause pain or tissue damage.
Water should be substituted for air in devices secured by air-filled cuffs or balloons (eg, feeding tubes, urinary catheters). Patients with a colostomy should wear a large bag and expect frequent filling due to expansion of intestinal gas.
Children are particularly susceptible to barotitis media Otic Barotrauma Otic barotrauma is ear pain or damage to the tympanic membrane caused by rapid changes in pressure. To maintain equal pressure on both sides of the tympanic membrane (TM), gas must move freely... read more and should be given fluids or food during descent to encourage swallowing, which can equalize pressures. Infants can be breastfed or given a bottle or pacifier. Precautions for children with chronic disease (eg, congenital heart disease, chronic lung disease, anemia) are the same as those for adults.
Jet lag (circadian dysrhythmia)
Rapid travel across multiple time zones disrupts the normal circadian rhythm Circadian Rhythm Sleep Disorders Circadian rhythm sleep disorders are caused by desynchronization between internal sleep-wake rhythms and the light-darkness cycle. Patients typically have insomnia, excessive daytime sleepiness... read more . Bright sunlight resets the internal clock. Exposure to bright late-afternoon or evening light delays the onset of normal sleep time, and exposure to early-morning light advances the biologic clock, so that sleep time is earlier than usual. Thus, managing exposure to light can help adaptation, particularly on the days after arrival in a new time zone. For example, people traveling westward could maximize exposure to bright afternoon light to help delay sleep time; those traveling eastward could maximize exposure to bright light in the early morning to help awakening and promote earlier sleep, for 3 to 4 days after arrival.
Short-acting hypnotics (see table Oral Hypnotics in Common Use Oral Hypnotics in Common Use Almost half of all people in the US report sleep-related problems. Disordered sleep can cause emotional disturbance, memory difficulty, poor motor skills, decreased work efficiency, and increased... read more ) may help people fall asleep at the appropriate local time after eastward travel. However, hypnotics may have adverse effects, such as daytime drowsiness, amnesia, and nighttime insomnia. Long-acting hypnotics increase the likelihood of confusion and falls among the elderly and should be avoided.
Melatonin Melatonin Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more , a hormone secreted by the pineal gland, may provide a time-of-night cue; however, large placebo-controlled trials showing melatonin’s safety and efficacy are lacking. Taking melatonin (0.5 to 5 mg orally before the desired sleep time) may help those who need to go to sleep earlier because they have traveled east across several time zones.
Some therapeutic regimens must be altered to compensate for circadian dysrhythmia. For example, insulin dosage and timing may require modification depending on the number of time zones traversed, time spent at destination, available food, and activity; glucose must be monitored frequently. Target plasma glucose levels should be increased; because so many changes affect levels, tight control is more difficult, and the risk of hypoglycemia is increased. Regimens may require modification based on elapsed rather than local time.
Decreased oxygen tension
In passenger jets at cruising altitude, with aircraft cabins typically pressurized to 8,000 feet (2440-m) above sea level, the partial pressure of oxygen is about 25% less than at sea level, which, because of the oxygen-hemoglobin dissociation curve (see Figure: Oxyhemoglobin dissociation curve Oxyhemoglobin dissociation curve Gas exchange is measured through several means, including Diffusing capacity for carbon monoxide Pulse oximetry Arterial blood gas sampling The diffusing capacity for carbon monoxide (DLCO)... read more ), represents a drop in arterial oxygen saturation of only about 4.4%. This decrease may be significant for people with severe heart or lung disease (see table Contraindications to Flying Contraindications to Flying Appropriate planning reduces the risks associated with travel, including air travel. Prior to travel, patients and their medical providers should review planned itineraries and relevant medical... read more ) but is harmless to most people; however, after 3 to 9 hours at that altitude equivalent, some people report discomfort (eg, headache, malaise).
In general, anyone who can walk 50 m or climb one flight of stairs and whose disease is stable can tolerate normal passenger jet cabin conditions without additional oxygen. However, problems may arise for travelers with moderate or severe pulmonary disease (eg, asthma, COPD [chronic obstructive pulmonary disease], cystic fibrosis), heart failure, anemia with Hb 8.5 g/dL (85 g/L), severe angina pectoris, sickle cell disease (but not trait), and some congenital heart diseases. When flying is essential, such patients can usually fly safely with specially designed continuous oxygen equipment, which must be provided by the airline. Mild ankle edema due to venous stasis commonly develops during long flights and should not be confused with heart failure.
Smoking can aggravate mild hypoxia and should be avoided before flying. Hypoxia and fatigue may increase the effects of alcohol.
Low cabin humidity
Dehydration may develop because of very low cabin humidity. It can be avoided with adequate fluid intake and alcohol avoidance. Contact lens wearers and people with dry eyes Keratoconjunctivitis Sicca Keratoconjunctivitis sicca is chronic, bilateral desiccation of the conjunctiva and cornea due to an inadequate tear film. Symptoms include itching, burning, irritation, and photophobia. Diagnosis... read more should instill artificial tears frequently to avoid corneal irritation resulting from low cabin humidity.
Motion sickness Motion Sickness Motion sickness is a symptom complex that usually includes nausea, often accompanied by vague abdominal discomfort, vomiting, dizziness, pallor, diaphoresis, and related symptoms. It is induced... read more is often triggered by turbulence and vibration and is made worse by warmth, anxiety, hunger, or overeating. Symptoms may include nausea, vomiting, sweating, and vertigo.
Motion sickness can be minimized before and during travel by moderating intake of food, fluids, and alcohol. Fixing the eyes on a stationary object or on the horizon can help, as can lying down and keeping the eyes closed. Other measures include choosing a seat where motion is felt least (eg, in the center of an airplane, over the wing), refraining from reading, and using an air vent. A scopolamine patch or an over-the-counter or prescription antihistamine is often useful, especially if taken before travel. However, these drugs can cause drowsiness, dry mouth, confusion, falls, and other problems in the elderly.
Uncomplicated pregnancy through 36 weeks is not a contraindication to air travel; high-risk pregnancies Overview of High-Risk Pregnancy In a high-risk (at-risk) pregnancy, the mother, fetus, or neonate is at increased risk of morbidity or mortality before, during, or after delivery. In 2017, overall maternal mortality rate in... read more must be individually evaluated. Flight during the 9th month usually requires a physician’s written approval dated within 72 hours of departure and indicating expected delivery date. However, policies may vary by airline. Seat belts should be worn below the abdomen, across the hips.
To prevent effects on development of the fetal thyroid, pregnant women should avoid prolonged use of water purification tablets that contain iodine. Pregnant women should consider delaying travel to areas where malaria is endemic because malaria can be more virulent in pregnant women. Mefloquine is thought to be safe for use during all 3 trimesters of pregnancy (see also Malaria Prevention Prevention Malaria is infection with Plasmodium species. Symptoms and signs include fever (which may be periodic), chills, rigors, sweating, diarrhea, abdominal pain, respiratory distress, confusion, seizures... read more ). When traveling, pregnant women should be particularly careful about following safe food guidelines and hand washing.
Pregnant women should not travel to areas with risk of Zika infection Zika Virus (ZV) Infections The Zika virus is a mosquito-borne flavivirus that is antigenically and structurally similar to the viruses that cause dengue, yellow fever, and West Nile virus. Zika virus infection is typically... read more .
Hypnosis Hypnotherapy Hypnotherapy, a type of mind-body medicine, is derived from western psychotherapeutic practice. Patients are put into an advanced state of relaxation and focused concentration to help them improve... read more and behavior modification benefit some people with fear of flying or claustrophobia. Fearful passengers may also benefit from a short-acting anxiolytic (eg, zolpidem, alprazolam) taken before and, depending on duration, during flight. Hyperventilation commonly simulates heart disease and may cause tetany-like symptoms; anxiety and hyperventilation can cause panic, paranoia, and a sense of impending death. Psychotic tendencies may become more acute and troublesome during flight. Patients with violent or unpredictable tendencies must be accompanied by an attendant and appropriately sedated.
Deep venous thrombosis Deep Venous Thrombosis (DVT) Deep venous thrombosis (DVT) is clotting of blood in a deep vein of an extremity (usually calf or thigh) or the pelvis. DVT is the primary cause of pulmonary embolism. DVT results from conditions... read more may develop in anyone sitting for long periods and may result in a pulmonary embolus. Risk factors include those for non–altitude-related deep venous thrombosis (eg, prior deep venous thrombosis, pregnancy, use of oral contraceptives—see table Risk Factors for Venous Thrombosis Risk Factors for Venous Thrombosis Deep venous thrombosis (DVT) is clotting of blood in a deep vein of an extremity (usually calf or thigh) or the pelvis. DVT is the primary cause of pulmonary embolism. DVT results from conditions... read more ). Frequent (every 1 to 2 hours) ambulation, short-movement exercises while seated, and adequate hydration are recommended; however, studies showing benefit from these measures are lacking. Drug prophylaxis (eg, aspirin, heparin) is not indicated, but travelers at risk of venous thromboembolism are advised to use properly fitted, below-the-knee, graduated compression stockings.
Turbulence may cause motion sickness Motion Sickness Motion sickness is a symptom complex that usually includes nausea, often accompanied by vague abdominal discomfort, vomiting, dizziness, pallor, diaphoresis, and related symptoms. It is induced... read more or injury. While seated, passengers should keep their seat belts fastened at all times.
Travelers with certain medical conditions or risks should carry appropriate documentation, drugs, and devices.
Travelers with known medical conditions should carry a medical record summary (including ECG for those with significant cardiac history).
Travelers subject to disabling illness (eg, epilepsy) or those with chronic disease should wear a medical identification bracelet or necklace.
Travelers with known histories of specific recurring conditions (eg, urinary tract infections, vaginal candidal infections, migraine headaches) should consider traveling with self-treatment drugs.
Travelers who need to carry opioids, syringes, or large amounts of drugs should have a prescription or verifying letter from a physician to avoid possible security or customs complications.
The following should be packed in a carry-on bag in case checked baggage is delayed, lost, or stolen:
Drugs, in original labeled containers
Extra eyeglasses or other corrective lenses (as well as a current written prescription for either)
Hearing aid batteries
Most implanted cardiac devices, including pacemakers and cardioverter defibrillators, are effectively shielded from interference from security devices. However, the metal content of some of these devices, as well as certain orthopedic prostheses and braces, may trigger a security alarm. A physician’s letter should be carried to avoid security difficulties.
People with specific dietary and medical needs should plan carefully and carry their own food and supplies. With several days’ notice, all airlines departing from or arriving in the US (and most others) can make reasonable efforts to accommodate passengers with physical handicaps and special needs, including those who require oxygen therapy. Wheelchairs can be accommodated on all US airlines and most foreign ones, but advance notice is advisable.
Some airlines accept passengers requiring more highly specialized equipment (eg, IV fluids, respirators) provided that appropriate personnel accompany the passenger and arrangements have been made in advance. If travelers cannot be accommodated on a commercial aircraft because of severe illness, air ambulance service is necessary.
Fair-skinned travelers are more vulnerable to sunburn at tropical latitudes and at high altitude. Use of high-SPF (30 or higher) sunscreen is advisable. When both sunscreen and insect repellent are used, sunscreen should be applied first, then, after at least fifteen minutes, insect repellent.