DENVER, CO — While flying from Phoenix to Minneapolis, Joseph I. Sirven, MD, heard the flight attendant's anxious voice over the loudspeaker, “Is there a doctor on board? Someone is in need of help.” Promptly volunteered by his wife, Dr. Sirven attended to a young woman who had just had her first seizure.
“It was quite an experience to do a neurological consultation at 35,000 feet in front of 170 passengers,” said Dr. Sirven, who is Director of the Comprehensive Epilepsy Center at Mayo Clinic-Scottsdale in Arizona. “Luckily, the woman recovered spontaneously, but it got me to wondering how often people have seizures aboard jets, and to want to know more about the issues and things we could do to prevent this problem from occurring.”
After speaking with colleagues, Dr. Sirven confirmed that his experience was not unique. He decided to systematically evaluate the problem with the help of David W. Claypool, MD, Con-sultant in Emergency Medicine at Mayo Clinic in Rochester, MN, and Director of Mayo Clinic MedAir, which provides medical services to Northwest Airlines.
Dr. Sirven's analysis of on-flight medical events – which he presented at the AAN Annual Meeting here – indicated that neurological symptoms were the single largest category of medical problems, accounting for 592, or 18.9 percent, of 2,042 medical incidents, and resulting in 312 diversions to the nearest suitable airport.
“Somewhere, there is about a case a day of some medical condition occurring in-flight,” Dr. Sirven said. Cardiovascular events were the most common indication for landing the aircraft, followed by neurological symptoms.
Dr. Sirven's data were based on a review of medical incidents recorded in the Mayo In-flight Advisory Report database from 1995 to 2000 for Northwest Airlines. This database reflects the travels of approximately 52 million passengers per year on a total of a little more than four million flights. The database includes 9.74 percent of all US passengers and 12.04 percent of all miles flown.
During the six-year period, there were 354 cases of dizziness or vertigo, 131 seizures, 37 headaches, 34 syncopes, 25 instances of pain, 21 cerebrovascular accidents, 10 traumas, six reports of numbness, six episodes of confusion, and two tremors.
Dizziness and vertigo were the most common reasons for a diversion due to neurological symptoms, followed by seizures and loss of consciousness. Seizures necessitated diversions when they occurred in clusters, evolved into status epilepticus, or resulted in injuries. Of the 31 diversions for seizures, there were five cases of status epilepticus, five clusters, seven prolonged post-ictal states, three injuries, two febrile convulsions, and nine patients who were diverted despite in-flight recovery.
Relatively few diversions were necessary for the remaining neurologic symptom categories. Dr. Sirven noted that although loss of consciousness and confusion did not occur frequently, they were the most likely symptoms to result in an emergency landing.
Using a conservative average figure of $50,000 for each diversion, Dr. Sirven estimated that neurological diversions cost nearly $9 million per year, while in-flight seizures were responsible for more than $2.5 million a year for all US airlines. Neither of these cost estimates included other associated medical costs, such as ambulance services or hospitalizations.
The figures were based on reports from medical directors at six major airlines on the average cost of diversions on their respective airlines; and then based on figures from the Airline Transport Association on the cost to fly a plane per minute.
Dr. Sirven observed that there is no industry standard in regard to flight diversions for medical emergencies. He suggested that further research include a prospective analysis of flight diversions to assess how they affect patient outcomes. Diversions due to stroke might need to be increased, given the short time period available for acute thrombolytic therapy, he said.
Further studies should also include an assessment of the benefit of adding antiepileptic drugs to in-flight medical kits. Dr. Claypool pointed out that commercial aircraft cabins are pressurized to an equivalent of 6,000 feet, not sea level, which results in “about 25 percent less oxygen available.” He suggested that more research is needed to determine the impact of this relative hypoxia in seizure patients.
“This is a unique project because no one had ever before looked at neurological problems aboard airlines. There appears to be a major issue of neurologic problems aboard airlines, and it seems worth studying more in depth.”
Dr. Claypool said that after the study is published – (Neurology 2002; (58): 1739–1744) – the research team will seek funding for a larger study that includes outcomes. “Outcomes are really the hardest part of evaluating emergency treatment in airliners. We need to follow those patients to find out what their real diagnosis was and evaluate whether the things we did or didn't do were beneficial to them.”
WHAT NEUROLOGISTS SHOULD ADVISE PATIENTS ABOUT FLYING
FAA Spokesperson Alison Duquette said airlines have the right to refuse passage to passengers who exhibit medical symptoms that may cause problems in-flight. “Clearly, the airlines would prefer that these passengers remain on the ground where they might receive the benefit of full medical services, ” she said.
Dr. Sirven suggested that neurologists advise their patients accordingly about flying:
* Individuals with chronic neurological conditions, such as seizures, headaches, and Parkinson disease, should always carry their medications on board rather than checking them in their luggage, and carry a medical alert bracelet.
* Patients who have had a neurosurgical operation within two weeks of flying, or a stroke within two weeks, should not fly.
* Avoid alcohol.
* Patients with well-controlled epilepsy should not hesitate to fly, but if they have seizures every day, precautions should be taken. Patients with seizures should not forget their medication.
* If patients are planning a trip that requires air travel, neurologists should wait for their return before prescribing a change in their medications.
WHAT IS THE AIRLINES' RESPONSIBILITY IN HEALTH EMERGENCIES IN FLIGHT?
The airplane captain is responsible for the passenger's health in the event of an emergency, according to Alison Duquette, spokesperson for the Federal Aviation Administration (FAA).
The captain can ask for medical volunteers or use air-to-ground medical consultation, such as that provided by Mayo Clinic's Departments of Emergency Medicine, Medical Transportation Service, and Division of Aerospace Medicine, to assess emergencies and guide the use of the onboard emergency medical kit.
These consultations help the captain decide whether the passenger's safety requires an emergency landing (diversion). Ms. Duquette noted that flight crews receive only 30 minutes to a few hours of training on first aid and volunteers with medical training may or may not be on board.
Another consideration is cost. The costs for emergency landings may range from $15,000 to $893,000. Patients with questions or concerns about medical conditions can contact their airlines; most have medical directors and others on hand who can address health issues and concerns.
MEDICAL KITS AND RESOURCES
Concerned about reports of heart attacks and deaths in the air, Congress mandated the Aviation Medical Assistance Act of 1998. This directive required an examination of air safety, as well as provided a Good Samaritan provision limiting the liability of airlines and nonemployee passengers who attempt to administer care in-flight, unless they are grossly negligent or exhibit willful misconduct.
As directed by Congress, the FAA collected data from 15 airlines that carried 85 percent of commercial domestic passengers from July 1, 1998 to June 30, 1999. There were 119 cardiac-related events, which resulted in 64 deaths.
NEW RULES FOR SAFETY
Automatic external defibrillators (AEDs) were used in 17 patients, which appeared to save four passengers. In light of this information, the FAA ruled in April 2001 that commercial airlines have until May of 2004 to equip their planes with AEDs. “The main thing you have to focus on is the training of flight attendants and the crew,” Ms. Duquette said, adding that, to date, 3,895 AEDs have been installed.
In addition, the FAA ruling has also upgraded the contents of the on-board medical kit. Until April 2001, the kit consisted of a sphygmomanometer, stethoscope, oral airway, syringes, needles, an antihistamine, 50 percent dextrose, epinephrine, and nitroglycerin tablets. New additions to the kit now include an automatic external defibrillator, nonnarcotic analgesics, aspirin, atropine, bronchodilator inhaler, lidocaine, saline, IV kit with connectors, an Ambue bag, and CPR masks.
Individual airlines are permitted to add additional medications to supplement these basic components. For example, Northwest Airlines includes diazepam, naloxone, and nalbuphine, while Air Canada adds haloperidol, morphine, Tylenol® #2, and diazepam. Other than diazepam, none of the kits include antiepileptic drugs. Dr. Sirven suggested that airline medical officers reevaluate the kits to make sure they are adequate for neurological events.