Medical emergencies in commercial air travel

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MEDICAL EMERGENCIES IN COMMERCIAL AIR TRAVEL Andy Jagoda, MD, FACEP, and Michael Pietrzak, MD, FACEP

Aeromedical history was made over the Himalayas on May 23, 1995, when a female passenger on British Airways developed acute respiratory distress with cyanosis. Two British physicians on board diagnosed a tension pneumothorax and, with impressive ingenuity, used a scalpel, a fork and knife, a wire coat hanger, a urinary catheter, Courvoiser brandy, and a bottle of Evian water to successfully perform a chest tube thoracostomy? This lifesaving intervention received international attention, and travelers around the world asked what resources would be available to them if they were in the same situation. It is predictable that the number of aeromedical emergencies will increase as the number of passengers, especially those with underlying disease, travel by air.* Morbidity and mortality could potentially be reduced by identifying passengers at risk and providing them with proper counseling and preventive interventions before travel. This article reviews the epidemiology of aeromedical emergencies, the medical supplies available on various commercial airlines, and management options for specific disorders. DEMOGRAPHICS

Four general categories of medical emergencies occur during commercial air transport: (1)emergencies related to the psychological stress associated with air travel; (2) medical problems directly related to the The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views or policy of the Air Force or the Department of Defense.

From Mount Sinai School of Medicine, New York, New York (AJ);and the Department of Emergency Medicine, George Washington University, Washington, DC (MP)

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Table 1. MEDICAL EMERGENCIES MOST COMMONLY REPORTED IN COMMERCIAL AIR TRAVEL Hyperventilation Syncope Allergic reactions Sinusitis Earache Bronchospasm

Angindmyocardial infarction Seizures Abdominal pain Trauma Gastroenteritis Drug overdose

'Not in order of frequency.

in-flight environment, such as changes in barometric pressure and dehydration; (3) in-flight mishaps resulting in trauma or lnhalation injury; and (4) unrelated medical emergencies that occur coincidentally with air travel. Approximately 3000 in-flight medical emergencies are reported to the Federal Aviation Administration (FAA) each year.5 Overall, using data from both domestic and foreign airlines, it can be estimated that 1 in 10,000 to 40,000 passengers will have a medical incident during transp0rt.l.7, 11, 15, 21 One in 150,000 air travelers will require the use of inflight medical equipment or drugs.5 Table 1 lists the most commonly reported medical emergencies during commercial air travel. Burns and trauma make up to 25% of inflight emergencies, whereas neurologic and cardiovascular categories comprise the most serious medical problem^.^, 8, 21 Fatalities from medical conditions during air travel are rare, with an estimated incidence of 0.3 to 1 per 1 million passenger^.^, 21 In-flight deaths usually occur in patients with no medical complaints before travel and are most frequently the result of myocardial disease (Table 2).7,13, 21 IN-FLIGHT PHYSIOLOGY AND PATHOPHYSIOLOGY

Many of the medical emergencies in air travel are directly related to the commercial aircraft's hypobaric environment. At cruising altitude, cabin oxygenation and humidification decrease and gases expand. Commercial aircraft fly at altitudes ranging from 28,000 to 45,000 feet; with pressurization, aircraft cabin pressure is maintained at the equivalent of Table 2. CAUSES OF IN-FLIGHT DEATHS ~~

Cardiac Predisposing acute medical problem* Pulmonary Central nervous system Trauma Overdose/suicide Unknown 'Cancer, prior trauma, etc.

56.0% 19.0%

8.0% 0.5% 0.5% 0.5% 15.5%

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6000 to 8000 feet. At an altitude of 6000 feet, the alveolar Po, is 71 mm Hg, while at 8000 feet the Po, drops to 59 mm Hg. In order for the cabin pressure, and thus the atmospheric Po,, to be equivalent to that at sea level, most commercial aircraft must descend to 22,500 feet.’ Gases expand in direct proportion to decreases in pressure, thus creating the potential for pathologic disturbances in those gas-containing cavities that do not have a mechanism for equilibrating pressures. Cabin pressurization minimizes gas expansion, though there will be an approximate 10%increase in gas volume. This poses a potential risk for patients with conditions that trap gas in a closed space such as sinusitis, eustachian tube dysfunction with or without otitis, or abdominal obstruction. Cabin humidity is generally below 20% saturation on most commercial aircraft. This does not present a problem for most healthy travelers; however, individuals subject to dehydration or with conditions, such as corneal abrasions where desiccation is problematic, may require medical attention. MEDICAL TRAINING AND EQUIPMENT

No international standards exist among the world’s commercial carriers regarding either the medical equipment and drugs stocked on each airline, or the level of first aid training provided for the crew. Commercial airlines are not legally responsible for providing medical care to passengers. Historically, in the beginning of commercial air travel, flight attendants were required to be nurses. Presently, flight attendants are instructed on basic first aid procedures, but many are not certified in basic life support. Some authors have recommended that all airlines provide basic first aid training to their flight attendants, with advanced training to senior personnel.’6 The medical kits stocked by several foreign carriers are e~tensive.’~ The medical kit stocked by British Airways, for example, contains a variety of cardiac drugs including those for advanced cardiac life support, narcotics, diazepam, digoxin, urinary catheters, suture materials, and an Ambu bag. In the United States, the FAA mandates that each domestic carrier maintain a medical kit that is separate from the airplane’s first-aid kit.2 The first-aid kits are not regulated but often contain aspirin, acetaminophen, occasionally ammonia inhalants, a decongestant nasal spray, and an assortment of band-aids and bandages. Several carriers now also stock a universal precautions kit that contains gloves and containers for body fluids. The medical kit carried by American carriers is limited and contains the following equipment: a blood pressure cuff and stethoscope, 3 oropharyngeal airways of various sizes, 4 syringes and 6 needles for drug administration, one 50-mL ampule of 50% dextrose, 2 single-dose 1:1000 dilution ampules of epinephrine, 2 single-dose diphenhydramine ampules, and 10 nitroglycerin tablets. Additional equipment, such as mouth-to-face ventilation masks and report forms, is added at the discre-

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tion of each airline.5 Humidified, high-flow oxygen, separate from the oxygen used during cabin depressurization, is also available on all aircraft. Current data on in-flight cardiac emergencies do not justify the placement of automatic defibrillators on domestic airline^.^, Quantas is one of the few airlines that carries semiautomatic defibrillators on longdistance flights.12 The relative frequency of congestive heart failure, seizures, asthma, nausea/vomiting, and pain-related disorders would suggest that the addition of an injectable benzodiazepine, diuretic, antiemetic, and narcotic, and the availability of an inhaled beta-agonist to the standard airline medical kit may be prudent. At present, the American Medical Association (AMA) supports the recommendation that physicians carry personal medical bags with supplies they feel comfortable using. This recommendation applies only to domestic flights, however, as many countries prohibit the import or export of medical supplies with the exception of those for personal use.12 Onboard medical kits are intended for the exclusive use of physicians, who are usually requested to provide professional identification. In special circumstances the aircraft’s captain has authority to approve its use by nonphysicians. Use of the kits relies on health care professionals volunteering their services, yet ”good Samaritan” laws do not fully address the air travel scenario. It has been estimated that the chance of finding a physician on board can approach go%, yet in one study of inflight deaths, physicians were involved in only 43% of the cases, whereas in another study of in-flight emergencies, physicians offered assistance in only 8% of cases7, Cottrell and co-workers5 reviewed the 1-year use of medical kits on United Airlines. They reported that the kit was used 362 times on 361 flights with the highest use during the winter months. Twenty-six percent of the health care providers reported that the kit was very useful, 55% reported it to be somewhat useful, and 18% found it to be of no benefit. The stethoscope and blood pressure cuff were the items most commonly used, whereas medications were used in only 17% of cases; similar usage was reported by Hordinsky and George.13Cottrell reported that 49% of patients with in-flight emergencies were taken to emergency departments, where 39% were consequently admitted to the hospital. OPERATIONALPROCEDURESANDUNSCHEDULED LANDINGS

During in-flight medical emergencies, it is usual operating procedure for the flight attendants to make a preliminary assessment of the patient, followed by an overhead request for physician assistance if needed. Flight attendants are not authorized to use the in-flight medical kit. The physician’s primary role is to provide patient care. Each airline also has established procedures to access a medical resource on the ground for direction. British Airways is currently in the process of

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installing satellite video and data links between their planes and physicians on the g r ~ u n d . ~ Physicians caring for a patient in-flight will be asked to provide input to the captain who is ultimately responsible for making decisions regarding alterations in the flight’s course and for arranging medical support to meet the aircraft when it lands. The captain must weigh both the seriousness of the patient’s condition and emergency landing options against the financial and time losses potentially incurred by the airline and its customers. In one study, only 14% of in-flight deaths caused and 4Yo8 of in-flight an unscheduled landing7 In other studies, 11%013 emergencies resulted in flight diversions. Cummins and SchubachX found that during a 1-year period, none of the seven emergencies that resulted in a flight path diversion would have suffered additional morbidity by the additional delay had the diversion not occurred. SPECIAL SITUATIONS Syncope Syncope is the most commonly reported in-flight medical e m e r g e n c ~ .In ~ ,one ~ ~ series it accounted for 29% of reported cases. The causes can be varied. There are a number of factors during air travel that can predispose a patient to events, in particular, dehydration, prolonged sitting, apprehension, and alcohol use. When evaluating a patient who experiences a syncopal episode during a flight, it is necessary to differentiate benign causes from life-threatening causes, such as cardiac dysrhythmias or internal hemorrhage. Evaluation must include a careful history including risk factors for cardiac disease and medication use, and a limited physical examination that focuses on hemodynamic and neurologic functions. Physical evaluation would typically include orthostatic vital signs (if feasible), assessment of the rhythm by taking the pulse, and auscultation of the heart. Hypoglycemia would need to be diagnosed clinically based on the history and physical findings. In managing the patient with syncope or near-syncope, efforts should be made to ensure that the patient is in a position where cerebral circulation is optimized. Most airline seats have very limited reclining capability, therefore laying the patient across a row of seats or moving the passenger to the cabin floor may be necessary. Oral hydration and abstinence from alcohol ingestion are prudent. Occasionally supplemental oxygen should be requested from the cabin crew. If a serious dysrhythmia or internal hemorrhage is suspected, begin consultations with the aircraft captain directly or through the flight attendant as soon as feasible. Pulmonary Disorders Patients with pulmonary disease should be screened by their physicians before air travel because decreases in PO, and humidification

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potentially predispose these patients to exacerbations of their disease?O, 12, 2o Consider providing humidified oxygen and bronchodilators for patients with pulmonary disease who experience respiratory distress in flight. In this instance, the enforcement of a nonsmoking environment is required owing to oxygen usage. Bronchodilators are not included in the medical kit carried by US national carriers. Owing to the high incidence of bronchospastic disease in the general population, however, it is likely that there will be at least one passenger present on the airplane who could lend his or her medication to the patient. If symptomatic relief is not achieved with these measures, request that the captain establish a sea-level cabin altitude. This will usually require a descent from cruising altitude to approximately 22,000 feet. A reassessment of the patient at this level will determine the need for emergency diversion or landing. Despite prolonged exposure during transoceanic flights at cabin altitudes of 8000 feet, high-altitude pulmonary edema is only rarely reported. This usually occurs in patients with congenital single pulmonary arteries. Oxygen and cabin altitude descent are required for successful treatment. Cardiac Disorders

Cardiac disease in and of itself does not preclude air travel. Ischemic heart disease is common in the adult US population. In one study, patients with known chronic obstructive pulmonary disease and angina were found to desaturate an average of 5.5%; however, all remained asymptomatic during air travel. Well-controlled angina is not considered a contraindication to air travel even in those patients with concomitant pulmonary d i s e a ~ e In . ~ those patients with little or no reserve, with uncontrolled congestive heart failure, or with uncontrolled dysrhythmias, however, air travel should be avoided unless absolutely necessary. If travel is necessary, these individuals should be accompanied by a health care professional with appropriate supporting equipment and medications. Space becomes a major factor in assisting patients with serious cardiac illness on airplanes. This is especially true if they must be laid flat as in the case of cardiopulmonary resuscitation (CPR).Few commercial airlines have reserved space for medical emergencies (exceptions include Air Afrique and UTA).” When CPR is necessary and time or space precludes moving the patient to the first-class section of the aircraft or areas in front of exits, it is generally recommended that the patient be moved into the aisle or that the armrests between seats be lifted and the patient be stretched across the seats with a briefcase or similar hard object placed behind the back.”,” If defibrillation is attempted, special efforts need to be made to ensure the providers and nearby passengers are not in contact with objects that may carry the current. Currently, no US national carriers have defibrillators on board. To maximize oxygenation and overcome the relative hypoxemia that

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results from flying at altitude, it is recommended that the rescuer providing ventilations breathe from a 100% oxygen supply, although there are no outcome data to support this. Ear and Sinus Disorders

The middle ear depends on a patent eustachian tube for drainage, without which there is risk for negative middle ear pressure creating a vacuum, pain, and potentially tympanic membrane rupture. Other symptoms associated with this condition include tinnitus, vertigo, and hearing loss. Failure to equilibrate pressures in the middle ear is referred to as otic barotrauma or aerotitis media. Otic barotrauma is reported to occur in up to 9% of air travelers6 Although barotrauma typically occurs on descent, patients with sinus mucoceoles in the sinuses may experience intense pressure build-up and pain as cabin pressure drops during ascent. Initial treatment for otic barotrauma involves instructing the passenger to perform a Valsalva maneuver or swallowing. Military flight surgeons often carry Politzer bags, which are sometimes useful in forcing air through the eustachian tube into the middle ear, thus correcting the pressure gradient. Use of a topical vasoconstrictor can be of benefit when attempting this maneuver. In extreme cases, some military flight surgeons have attempted in-flight pressure releases by using an 18gauge steel catheter to perform a myringotomy, though this has a significant risk in an unstable aircraft and is not routinely recommended. If the patient’s pain is debilitating, the physician should discuss a cabin altitude adjustment with the captain. Preventive measures for barotrauma may prove beneficial. In one prospective study of passengers with a history of recurrent ear discomfort during air travel, 120 mg of pseudoephedrine 30 minutes before departure was found to decrease the incidence of barotrauma from 62% in the placebo group to 32% in the decongestant group. No significant side effects were reported.6 Patients with acute otitis media should avoid air travel until they are able to effectively Valsalva and clear their ears. Individuals with complete middle ear effusions (serous, purulent, of hemorrhagic) will theoretically have no difficulty with altitude changes. Gastrointestinal Disorders

Ascent to altitude may result in gas expansion causing abdominal distention and distress in some patients. This is usually not a significant problem and one that can be minimized by wearing loose-fitting clothing and avoiding gas-producing foods before travel. On the other hand, patients with recent abdominal surgery, history of obstructions, or gastrointestinal hemorrhage are at greater risk from gut distention and

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should not fly for at least 10 days after surgery. In cases where abdominal distress is severe, descent to 22,500 feet may result in enough gas compression to alleviate the patient's symptoms."

Anxiety From Flying It is estimated that up to 15% of the population has enough anxiety from flying that prevents them from air travel." When one of these individuals must fly, it is reasonable to premedicate them with diazepam 2 to 5 mg orally three times a day beginning 24 hours before flying and instruct them to increase each dose up to 10 mg if needed. Theoretically, medications with anticholinergic properties should be avoided because they may decrease gut motility and result in abdominal discomfort during travel.

Dysbarism Despite the widespread knowledge of dysbarism risk factors, some divers attempt air travel shortly after diving. The ascent to cabin pressures consistent with an altitude of 8000 feet can precipitate gas evolution. This is an indication for maximum cabin pressurization, immediate descent, and delivery of oxygen for nitrogen washout. The flight should be diverted to the closest airfield that has rapid access to a hyperbaric facility. Emergency physicians must be aware that this can occur some time after air travel is completed. In these cases, the diver will usually offer the key historical information.

Economy Class Syndrome The "economy class syndrome" refers to the development of vascular thrombosis during a prolonged flight. This syndrome is attributed to immobilization, specifically the position of economy class seating, which compresses the popliteal and femoral veins promoting stasis. To prevent stasis, it is generally recommended that passengers routinely ambulate during long flights. Periodic leg exercising in flight has not been shown to significantly alter fluid retention in the legs; however, it should help minimize thrombis f~rmation.'~ Passengers who develop deep vein thomboses in flight are often found to have risk factors in addition to those of the prolonged flightF2 In the same study, one half of the economy class syndrome patients had pulmonary embolism. Preventive measures are key for the individuals at risk. If pulmonary embolism occurs in flight, few available interventions are helpful except for oxygen and descent for definitive care.

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Trauma Management of even minor trauma on an aircraft is challenged by turbulence, as well as by space and equipment constraints. Immobilization is key for c-spine and fracture management. There are numerous materials of opportunity in the aircraft cabin including pillows, blankets, and various rigid objects. With lower extremity trauma, elevation is imperative as swelling readily occurs. CONCLUSION

In-flight medical emergencies occur frequently, but they are fortunately rarely life-threatening. To help provide medical care in the event of an emergency, the FAA requires that all US commercial carriers maintain a medical kit. This kit is minimal compared with that of many foreign carriers and grossly inadequate for managing many medical conditions. Use of the medical kits is voluntary and restricted to passengers who are health care providers. Minor trauma, syncope, and ENT problems comprise the majority of non-life-threatening events, whereas cardiopulmonary problems constitute the most common category of lifethreatening complaints.

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15. MacLaren R. In-flight medical care by flight attendants-An

assessment of overall needs. 1982 meeting of the Aerospace Medical Association. Washington, DC, Aerospace Medical Association, 1982, pp 305-306 16. Millett D: Final report of the sub-committee on the training of flight attendants in first aid. Aviat Space Environ Med 59:992-993, 1988 17. Mohler S, Nicogossion A, Margulies R: Emergency medicine and the airline passenger. Aviat Space Environ Med 51:918-922, 1980 18. Rodenberg H: Medical emergencies aboard commercial aircraft. Ann Emerg Med 16:1373-1377, 1987 19. Schocken V, Lederer L: Unscheduled landings for medical reasons: A five year survey of the experience at American Airlines. In Busby D (ed): Recent Advances in Aerospace Medicine. Dordrecht, the Netherlands, D Reidel, 1970, pp 126-129 20. Schwartz J, Bencowitz H, Moser K Air travel hypoxemia with COPD. Ann Intern Med 100:473477, 1984 21. Speizer C, Rennie C: Prevalence of in-flight medical emergencies on commercial airlines. Ann Emerg Med 18:26-29, 1989

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