The medical safety of air travel depends on the nature and severity of the traveler’s preflight condition and factors such as travel duration and frequency of travel, use and frequency of inflight exercise, cabin altitude pressure, availability of medical supplies, (including automated external defibrillators and supplemental oxygen), infectious diseases of other travelers, and the presence of health care professionals on board. In-flight medical emergencies are increasing because there are an increasing number of travelers with preexisting medical conditions. Air travel passengers are susceptible to a wide range of flight-related problems: pulmonary (hypoxemia, spontaneous pneumothorax), venous thromboembolism (VTE), infections, cardiac, gastrointestinal, ocular, immunologic, syncope, neuropsychiatric, metabolic, trauma, and illicit substance-related conditions. Air-travel risks are higher for those air travelers with preexisting medical conditions: pregnancy, pulmonary diseases (chronic hypoxemia, asthma, chronic obstructive pulmonary disease, diffuse cystic lung diseases), thromboembolic disorders, cardiovascular diseases, neurologic conditions (epilepsy, stroke), recent surgery or trauma, diabetes mellitus, cancer, compromised immune system, infectious diseases, mental illness, and substance dependence. Occupational and frequent flyers are also at risk for accumulative radiation exposure, cabin air quality, circadian disturbance, and pressurization problems.
Hypobaric hypoxia is the underlying etiology of most serious medical emergencies in flight due to cabin altitude. Requirements for commercial aircraft are to maintain cabin pressurized to the equivalent of 8000 feet or less. Despite commercial aircraft pressurization requirements, there is significant hypoxemia, dyspnea, gas expansion, and stress in travelers, particularly in those with underlying pulmonary disease.
Air travel has been the main focus of medical reviews on travel-related VTE; however, any form of prolonged travel involving immobilization is associated with increased risk of VTE (now referred to as “traveler’s thrombosis”). VTE risk is more relevant for those passengers with additional VTE risk factors. Risks for VTE in long-distance travelers include the following: (1) travel involving immobilization for 4 or more hours, (2) hypercoagulable disorders (eg, Factor V Leiden, deficiencies in proteins C and S or antithrombin, elevated factor VIII, hyperprothrombinemia, antiphospholipid syndrome), and (3) acquired risks (eg, previous VTE, recent surgery, stroke or trauma, active malignancy, obesity, pregnancy or postpartum state, oral contraceptives or hormone therapy, advanced age, immobilization or limited mobility inflammatory bowel disease, and nephrotic syndrome). Prevention measures may include wearing graduated compression stockings; frequent exercise and position changes during travel; and the use of thromboprophylaxis, such as low-molecular-weight heparin (LMWH) or direct-acting oral anticoagulant (DOAC) (see Chapter 14).
Air travel is not advised for anyone who is “incapacitated” or has any “unstable conditions.” The Air Transport Association of America defines an incapacitated passenger as “one who is suffering from a physical or mental disability and who, because of such disability or the effect of the flight on the disability, is incapable of self-care; would endanger the health or safety of such person or other passengers or airline employees; or would cause discomfort or annoyance of other passengers.” Unstable conditions include active pneumothorax, advanced pulmonary hypertension, acute worsening of an underlying lung disease, ...