Incidence studies

We conducted a MEDLINE search in March 2010 using search terms relevant to aviation medical emergencies and extracted incidence studies and high quality topic summaries published between 1980 and 2010. Reference lists of selected articles were reviewed to identify additional relevant publications.

The incidence of medical incidents during commercial air travel is unknown. MedAire, a medical assistance company that provides remote assistance to several commercial airlines in the United States, responds to an average of 17,000 cases per year. Given the absence of a national (or international) registry of incidents, reported numbers of cases from individual airlines and telemedicine providers cannot be generalized to an overall estimation of incidence.

Table 1 demonstrates the wide range of estimates generated by analyzing data from single airports or carriers.9–16 Most are retrospective cohort studies. Qureshi, et al,13 in a study published in 2005, retrospectively studied data from a single international carrier and characterized 507 medical incidents reported over a 6-month period in 2002. Dowdal, et al,9 also performed a retrospective study using a single airline over 1 year and found the incidence of medical incidents to be 1 per 11,000 passengers.

Table 1.

Study characteristics and incidence of in-flight medical emergencies.

Multiple airline studies include the study by Sand et al,11 which was a retrospective study of incidents from 2 European airlines over the course of 5 years, demonstrating an incidence of 14 incidents per billion passenger kilometers. This is comparable to the study by Hung et al,10 a 5-year retrospective cohort study that demonstrated an incidence of 11.6 cases per billion passenger kilometers.The variation of incidence, flight diversion, and cardiac arrest data underscores the need for standardized, system-wide reporting and data tracking.

Common In-Flight Medical Events

Table 2 provides a breakdown of the types of in-flight medical incidents reported.9–16 Once again, the lack of standardized data sources and the overlapping categorizations become evident through the wide-ranging results. The table nevertheless highlights common complaints and alludes to the predominant organ systems affected by the in-flight environment. Syncope, gastrointestinal upset, and respiratory symptoms were among the common medical complaints reported. Chest pain and cardiovascular events were also noted, and these cases were often associated with diversion.7,9

Table 2.

In-flight emergencies by diagnosis.

The data presented by Sand et al11 indicated that syncope was the most common type of in-flight medical emergency. Baltsezack et al12 noted that gastrointestinal complaints were the most common. Qureshi et al,13 demonstrated that the exacerbation of pre-existing diseases (usually respiratory) was the most common cause of an in-flight medical emergency, and syncope and respiratory conditions were the most common complaints. A study focused only on pediatric medical consultations requested from a single airline noted a high incidence of infectious disease complaints in addition to respiratory and neurologic symptoms.17 Each incident described was likely the product of a combination of contributing factors, including patient co-morbidities, the flight environment, and alcohol and drug use or withdrawal.

What’s Available in Flight?

The FAA requires all American commercial airlines weighing 7,500 pounds or more and serviced by at least one flight attendant to carry an automatic external defibrillator (AED) and an enhanced emergency medical kit. AED use during the commercial flight environment has been validated as safe and effective.18 Flight attendants must be CPR and AED certified every 2 years.

The standard emergency medical kit on American commercial airlines, which is based on recommendations by the Aerospace Medical Association’s (AsMA) Air Transport Medicine Committee, includes a stethoscope, bag valve masks, syringes and intravenous catheters in a range of sizes, and commonly used medications listed in Table 3.19 Several medications are listed as drug types, including “bronchodilator,” “antihistamine,” and “analgesic,” so the specific medication included may vary from one kit to another. Flight attendants are trained to be familiar with the contents of the kit, and its seal is examined during every pre-flight check and restocked after it is used. According to FAA regulations, a flight may not take off if it is missing the medical kit or AED. Flight attendants may only use the equipment and medications under the direction of a licensed medical provider. For minor medical complaints, flight attendants may use a “first aid” kit that is stocked separately. Physicians requiring additional equipment or medications (e.g. a glucometer) can ask flight attendants to make an overhead announcement requesting the items from other passengers.

Table 3.

The emergency medical kit.

All United States (U.S.) airlines are required to carry the standard kit and many supplement its contents with additional equipment and medications. There are, however, no international regulations requiring a complete kit to be available overseas. The International Air Transport Association (IATA) does not regulate the contents of emergency medical kits of international airlines, although it does endorse the AsMA’s recommendations. An international study evaluating the medical kits stocked by 32 European airlines revealed a high degree of variability, with several kits evaluated to be inadequate to administer emergency care.20

A growing number of airlines use the services of remote emergency response centers. “MedAire,” “The First Call,” and the University of Pittsburgh Medical Center’s “StatMD,” for example, offer 24-hour consultations via call centers staffed by physicians. If medically trained passengers volunteer their assistance they should coordinate with cabin crew and a response center physician. If a call center physician is not available, the volunteer physician must work with cabin crew and can suggest treatment or diversion options.

Medico-legal Issues

Federal legislation contained in the Aviation Medical Assistance Act of 1998 has provided limited protection and guidance for physicians and other medical professionals who volunteer their services during flight. Volunteers must be “medically qualified” and receive no monetary compensation in order to receive protection.21

The legislation states that “an individual shall not be liable for damages in any action brought in federal or state court arising out of the acts or omissions of the individual in providing or attempting to provide assistance in the case of an in-flight medical emergency unless the individual, while rendering such assistance, is guilty of gross negligence or willful misconduct.” To date there are no documented cases of a physician being sued for providing assistance during an in-flight incident.7,22,23

While physicians have no obligation under U.S. law to volunteer, one can argue that they have an ethical obligation to do so, especially if they are specifically trained to respond to undifferentiated medical emergencies.

Volunteer physicians should document their assessment and interventions administered using a standard airline medical incident form if available, or on a blank sheet of paper if a form is not available. If possible, the volunteer physician should request a copy of the medical document or form for their personal records. If a patient requires ongoing monitoring and therapy, the volunteer may need to stay by their side for the duration of the flight. Once the plane lands, the volunteer can hand over care to on-the-ground medical staff who can transfer the patient to an appropriate facility.

Approach to patient and guidelines

A 2002 article published in the New England Journal of Medicine by Gendreau et al,22 offers recommendations for volunteer physicians faced with an in-flight medical incident. The authors’ key points and others are outlined in Table 4. Table 5 outlines evaluation and management considerations for specific in-flight medical incidents.

Table 4.

General approach to managing in-flight medical incidents.

Table 5.

Approach to common in-flight medical incidents.

If the patient’s condition is unstable and requires immediate formal medical attention, the physician may recommend diversion of the flight to the nearest airport capable of landing the aircraft and with access to appropriate medical facilities. The act of diverting a full aircraft to the nearest city is expensive, estimated to range between $3,000 and $100,000 depending on the size of the plane and costs of additional fuel and passenger re-routing, and has far-reaching consequences.22 Diversion is usually made in consultation with ground-based medical expertise and should account for regional medical resources along the flight path. The final decision to make an emergency landing rests with the pilot in command. An article published by Ruskin et al23 advised diversion for unremitting chest pain, shortness of breath, or severe abdominal pain. Grendreau et al22 add stroke, persistent unresponsiveness, refractory seizures, and severe agitation to this list. A 2010 study reviewing 4 years of flight diversion data from Air Canada revealed that the majority of diversions occurred following cardiac complaints.7Regardless of the presenting symptom, in-flight or ground-based providers must assess a patient’s stability and perceived medical condition based on the limited clinical information available and then make a risk-based recommendation. Factors affecting this decision include the differential diagnosis of the patient’s condition, available in-flight resources, the patient’s response to initial treatments, and ground resources along the flight path. International flights that traverse oceans or large tracts of sparsely populated land may have a lower threshold for diversion before crossing these spaces given the paucity of resources once they are entered.7

In the case of multiple volunteers or a severe incident requiring a team approach, health providers should introduce themselves, their level of training, and their specialty in order to determine who should take the lead role. In some cases, a sub-specialist physician (e.g. a neonatologist) should defer to other personnel (e.g. an ED nurse or advanced paramedic) when responding to incidents beyond the scope of their training and experience.