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 those patients who are unstable and too ill to travel by commercial aviation.
Commercial airliners exist as a method of transportation of large numbers of passengers from origin to destination. They are not intended as a medical transportation facility and should not be treated as such. However, due to the large number of people traveling, it is inevitable that some with known or unknown medical problems will travel, and the environment of the aircraft cabin must be taken into consideration. In general, an understanding of the aircraft flight physiology must be addressed first. Further information regarding air ambulance transportation will be covered in Section 7.2.
Commercial airliners use pressurized cabins and supply the air by pumping in outside air, either by a separate pumping mechanism or bleeding the air off the compressor section of the jet engines powering the aircraft. As a result, the supplied air inside commercial airliners is extremely clean and dry. For example, an aircraft flying at 37,000 feet would provide air to a cabin that has a relative humidity of only 1-2%, but is biologically virtually sterile. The temperature constraints inside most commercial cabins during flight are in the 65-75°F range and air quality content is regulated so that an entire turnover of the air inside the cabin occurs every 3-5 minutes. Some of this air may be recycled, but if recycling occurs it is passed through high efficiency particulate air filters (HEPA), which remove any biological content added by the occupants of the cabin. In aircraft where smoking is prohibited (this includes all U.S. commercial flights), environmental tobacco smoke is not a significant consideration and the only source for biological contaminants will include exhaled products of occupants, such as viruses and bacteria, or clothing contaminants, such as fungi and dander, particularly cat and dog dander.
The pressure inside a commercial aircraft cabin will not exceed 8,000 feet above sea level or approximately 2,500 meters. Barometric pressure will decline from 760 mmHg at sea level to a minimum of about 550 mmHg at maximum cabin altitude. In a normal individual, this would cause arterial oxygen saturation to fall from 98% to 88%. Additional concerns in flight include vibration, turbulence, noise, and barometric pressure changes. It is important to remember that the composition of the cabin air remains essentially unchanged, with ambient oxygen content in the 20.5-21% range at all times, even under maximum crowding of the cabin. Carbon dioxide levels are regulated to a maximum of 1500 parts per million, although occasional slight higher excursions will occur due to the use of carbonated beverages and dry ice. These limits are derived from using CO2 as a surrogate for measuring odors, not due to health limits from CO2 itself, which are several times higher.
Certain individuals should not travel as passengers. Basic criteria for patient travel require the passenger be stable and travel should not represent a potential threat to the health and safety of the passenger nor to the health and safety of the other passengers and crew. Exclusions would include individuals with infectious diseases likely to be spread within the aircraft cabin, such as active tuberculosis, mumps, measles or uncontrolled diarrhea. Those with lice could spread the infestation to others. Individuals likely to harm or threaten themselves or others should also be excluded. In the past, such individuals have attempted to claim that they are disabled and therefore entitled to special consideration. However, the health and safety of the crew and other passengers may override any individual’s right to accommodation.
Specific medical conditions should be addressed by the individual challenges of flight. The aircraft is a slightly hypoxic environment which may negatively impact cardiac conditions. Persons who have had a myocardial infarction within two weeks or who have an unstable cardiac condition, congestive heart failure, recent open-heart surgery and unstable cardiac rhythms are contraindicated. While most commercial aircraft do carry automatic external defibrillators, limited success with these devices does not insure survival, much less survival without severe morbidity.
If the treating physician is concerned about the mildly hypoxic environment, Oxygen supplementation can be ordered. In the United States, this is limited to either 2 L or 4 L per minute flow rates. Use of oxygen in flight is a medical prescription and must be supplied by the air carrier. The individual patient is not permitted, per FAA regulation, to bring on board their own oxygen supply. The air carrier should be contacted at least 48 hours prior to travel to coordinate the use of oxygen. Likewise, patients with chronic pulmonary disease will be more hypoxic at altitude and their condition may be mildly exacerbated by the extremely dry environment, prompting consideration of humidified oxygen.
The most common medical emergency in flight has historically been asthma occurring in non-compliant patients. Patients should carry their own medication with them on their person and not consign it to checked luggage, which may be securely stowed in a baggage compartment and unavailable in the event of an attack.
Deep vein thrombosis has been associated with commercial flying; however, statistical studies do not demonstrate any higher risk for DVT in aircraft compared to any other environment. Any sitting for a prolonged period of time, such as a bus or in a movie theater, creates a potential risk for deep venous thrombosis or the further complication of pulmonary embolus. Therefore, passengers should be encouraged to move about the cabin every 60-90 minutes and to maintain as much leg space as possible. They should also adequately hydrate themselves. Use of other devices such as elastic stockings, aspirin or subcutaneous heparin has not been validated in prevention of DVT in aircraft or other settings. Certainly an individual with a known DVT should not place themselves in any situation where the condition can be exacerbated.
Obstetrical patients in later stages provide a significant risk of precipitating delivery during flight; pregnancy past 32 weeks should be carefully considered for restriction from flight and those past 36 weeks should be prohibited from flying. An aircraft is not a delivery room. Additional concern about deep venous thrombosis in the pregnant patient may be another issue.
Patients with orthopedic concerns must take into account their limited ability to move. Casts, if applied within 24 hours, may need to be cut lengthwise, or “bi-valved” to avoid expansion of the tissues from inflammation and edema, causing circulatory compromise. Individuals who are unable to move or sit in a conventional seat may request specialized seating. Accommodation is required under the Airline Passenger Assistance Act and the Americans with Disabilities Act, although 48-hour notice is also obligatory. Individuals who require mobility assistance devices, such as wheelchairs, are entitled to have these transported at no additional charge. However, the passenger should arrive significantly before scheduled departure time in order to permit the wheelchair, particularly if it is battery-powered, to be safely packaged and stowed for flight.
Psychiatrically, patients who are well controlled on their medications should not have difficulties in flight. However, anxiety and fear of flying could lead to precipitous actions. Appropriate and judicious use of anxiolytic medications is sometimes indicated. Caution should be exercised when using psychotropic medications because of idiosyncratic reactions that could cause agitation in flight. Some sedatives can suppress respiration in pulmonary-compromised patients. Passengers with mild dementias, such as early Alzheimer’s, are subject to increased agitation in unfamiliar surroundings, “Sundowners’ Syndrome”. If the personal physician has significant concerns, a medical attendant should be assigned to accompany the traveling patient.
Diabetes mellitus controlled either by oral agents or insulin may be complicated by air travel. Disruption of meal planning and sleep schedule can seriously impact glucose regulation. The passenger should carry a supply of insulin and syringes, but take care to appropriately dispose of syringes in the needle disposal kits provided on the aircraft and not leave these under seat cushions. Such irresponsible actions on the part of some diabetics have created blood-born pathogen hazards for subsequent occupants of the seat and airline employees who clean up after the flight.
Post-surgical conditions should be, in general, safe once the anesthesia recovery period is complete and there is no significant residual trapped gas in the body. Small amounts of residual gas in the abdomen may not be of significant concern, although anticipated expansion by 25% of bubble size should be anticipated under a normal flight operation. Under no circumstances should any postoperative patient who has gas either within the eye or the central nervous system (following spinal tap, myelogram, or pneumoencephagram) be permitted to fly until all gas has been absorbed. Even minimal expansion of gas in these spaces can cause reflex cardiac arrest.
Scuba divers should take normal precautions following dives requiring decompression stops. Twelve hours should elapse before flying after a single dive without compression stops. For any other dive where decompression stops are required or following multiple dives, at least 24 hours should elapse prior to flying. If an individual has been treated for decompression sickness, a much longer period of time should elapse and a hyperbaric specialist consulted prior to permitting the patient to fly.
The airlines have medical departments and consultants available for consultation prior to flight. Some airlines have in-flight consultation via telemedicine. Passengers should be aware that aircraft are not equivalent to a hospital emergency room and airline medical kits are designed to handle only the most basic of emergencies. Unstable patients should not travel by commercial airlines, and if air travel is necessary, use of an air ambulance should be considered.
EXCERTED FROM: FEDERAL AVIATION AGENCY Guidelines www.faa.gov
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