An in-flight medical emergency occurs about once in every 200 commercial airline flights and especially on long-haul and international flights.

Considering our distance from exotic tourism hotspots and major medical conferences, it’s likely that every well traveled Australian doctor can expect to hear the call ‘Is there a doctor on board?’ more than once during their career.

A study, published in JAMA Network Open [link here], found inflight medical emergencies occur more often than previously estimated. A 2013 study found the incidence was one event per 604 flights.

Using data from the clinical database of MedAire, which provides ground-based medical guidance to more than 100 airlines from five continents, the study identified 77,790 in-flight medical events across 84 airlines between January 1, 2022 and December 31, 2023.

The median incidence of in-flight medical events was 1 per 199 flights, with considerable variation among carriers, ranging from 1 per 114 flights to 1 per 480 flights.

The study said most reported events occurred on international flights (67.6%), with long-haul routes (49.6%) accounting for the largest proportion. Aircraft diversions were rare, occurring in only 1.7% of events.

Who will you see?

Affected passengers were mostly female (54.4%) with a median age of 43 years.

The most frequent diagnosis categories were neurological (36.1%), gastrointestinal (21.5%), respiratory (7.7%) and cardiovascular (5.7%). The most common presenting symptoms were syncope/near-syncope, vomiting, dyspnea, seizure, abdominal pain and chest pain.

Oxygen therapy was the most frequent intervention (40.8%) for in-flight medical events, with other cases requiring administration of nonnarcotic analgesics (15.2%) and antiemetics (14.9%).

CPR was required in 0.4% of events while an AED shock was subsequently applied in 14% of those events.

Fortunately, most incidents only required in-flight advice and treatment (53.0%), 15.8% required further treatment on landing by airport-based medical personnel then released, while only 7.7% required transfer to hospital for further care and 0.4% died.

Passenger volunteers with a medical background assisted in 25,570 events (32.9%) but were overrepresented in events requiring an aircraft diversion (79.2%) or deaths (78.9%). Other volunteers during inflight medical emergencies included nurses and paramedics.

Passenger deaths were mostly in older patients (median age 70 years) and mostly due to acute cardiac emergencies.

The study found the highest odds of aircraft diversion were with suspected stroke (AOR 20.35), acute cardiac emergency (AOR 8.16), and altered mental status (AOR 6.96).

Suspected stroke (AOR, 4.48; 95% CI, 2.92-6.87) and seizure (AOR, 2.45; 95% CI, 1.93-3.11) were associated with subsequent transport to a hospital.

Why does it happen?

The study said the commercial airspace represents a “suspended metropolis” with about 1.5 million people in the sky at any given moment.

“Considering the sheer volume of air travelers, in-flight medical events may occur simply by chance, as medical issues that would otherwise arise on land instead unfold during a flight.”

However the growing trend of medical tourism and the physiologic stressors of air travel may further contribute to in-flight medical events.

It noted that physicians were required to intervene when called on during an emergency in many European countries and in Australia and were protected by Good Samaritan legislation for volunteer responders.

An invited commentary in the journal [link here] said it was “heartening” to see the willingness of medical volunteers to assist patients in need in the daunting environment of a commercial aircraft at altitude with limited resources.

They also commended the study for providing valuable insight into inflight medical events for the many stakeholders involved.

“The use of such a large amount of high-quality data is useful in many ways for many groups of involved professionals and has the potential to inform policy, flight crew training, and aircraft diversion protocols,” it said.

“Beyond these conclusions, this study can also assist in determining the contents of the on-board medical kit and other medical supplies, assisting passengers with chronic illnesses and their primary health care professionals in decision-making regarding airline travel, and creating and/or guiding the development of regulations and requirements regarding in-flight medical events and inflight medical emergencies.”