In-flight allergic events requiring epinephrine appear rare

Key takeaways:

• 3% of the in-flight medical emergencies (IMFEs) reported by a ground-based medical service (GBMS) between January 2017 and December 2019 were related to allergy.
• The GBMS recommended epinephrine administration for 398 of 4,230 cases, with 328 receiving at least one dose.
• The researchers calculated the incidence of severe allergic reaction requiring epinephrine to be one event per 12.5 million passengers.

In-flight medical emergencies involving allergic reactions appeared rare, suggesting air travel is safe for patients with allergies when precautions are in place, according to a study in Annals of Allergy, Asthma & Immunology.

Allergists can best educate their patients about how to prepare for potential emergencies when travelling, Sangeetha Mohan Kodoth, MD, of Allergy Specialists of Knoxville, and colleagues wrote.

Historical data show in-flight medical emergencies (IFMEs) occur in one per 11,000 passengers. When medical events occur on commercial flights, cabin crews first ask if any health care professionals are on board are willing to volunteer. Next, crews communicate with ground-based medical services (GBMS) that employ physicians trained in emergency medicine to get real-time advice for treatment.

In this study, the researchers examined data from 140,579 IFMEs that occurred between January 2017 and December 2019 and were reported by MedAire, which provides GBMS to airlines in the United States. Of the cases recording age, 11.9% involved children aged 12 years and younger.

Overall, 4,230 unique cases (3%) were identified as allergic events, which occurred on 63 airlines from 39 different countries.

GBMS recommended epinephrine administration for 398 passengers, with 328 (82.4%) receiving at least one dose. When patients who did and did not receive epinephrine were compared, the researchers found statistically significant differences in:

• involvement of volunteers (OR = 3.19; 95% CI, 2.43-4.16);
• availability of autoinjectors (OR = 2; 95% CI, 1.55-2.58);
• flight diversion (OR = 11.21; 95% CI, 3.6-34.89); and
• hospital transport (OR = 6.58; 95% CI, 4.62-9.38).

Children aged 12 years and younger were less likely to undergo epinephrine administration (OR = 0.36; 95% CI, 0.23-0.57), whereas older passengers had higher likelihood.

Of the passengers who received epinephrine, 73 (22%) were transported to the hospital and 76 (23%) had carried their device on board, with 17 cases (5.2%) requiring flight diversion. Of those requiring flight diversions, 15 were aged older than 12 years, and one was aged younger than 6 years.

An additional four diversions occurred among patients who did not receive epinephrine, two of which involved passengers aged younger than 6 years. In one of these cases, parents declined epinephrine and requested the diversion. In the second case, the medical volunteer was unwilling to administer intramuscular epinephrine to the child.

According to MedAire, tree nuts or peanuts provoked the need to administer epinephrine in 66% of the 145 passengers whose triggers were recorded. Triggers were not documented for the other 183 passengers who received epinephrine.

In a secondary analysis of the 51 airlines that consistently use GBMS for all IFMEs, the incidence of allergic events was 0.91 cases per million passengers (interquartile range [IQR], 0.48-2.56 cases per million), or one allergic event per 1,039,927 passengers.

Specifically, there were 0.08 cases per million passengers (IQR, 0.02-0.16 cases per million) of severe in-flight allergic emergencies requiring epinephrine administration, or one event per 12.5 million passengers.

No fatalities were reported, and patients had access to epinephrine in all allergic events. The International Civil Aviation Organization requires epinephrine to be stocked on all commercial flights, although crew members are only trained in basic life support and first aid. They are not permitted to administer intramuscular or IV medications.

These limitations underscore the importance of educating patients and parents of patients about carrying their medications and about early epinephrine administration, the researchers wrote. Further, the researchers suggested that the allergy community engage in advocacy to improve crew training and airline preparedness.