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Think Flying Horses, Not Zebras

How to tackle a medical emergency at 35,000 feet

The New Physician March 2010

“Aid in the Air,” Dr. Lizbeth Marie Dalaza’s article in last October’s TNP, was a wonderful case report on an in-flight emergency managed by a medical student. I myself “got the call” on a flight during my second year of medical school—a time when my brain was overstuffed with scientific knowledge but lacking in the practical variety.

Initially I was told that “Carl” had fainted, but on history and physical, it became clear that this had been a 20-second seizure. Unlike Dalaza’s patient, my new patient was lucid—if postictal at first—and able to answer my questions and cooperate with a physical exam. Carl’s exam was within normal limits except for constricted and minimally reactive pupils in the dark cabin. While the differential diagnosis for an unprovoked first-time generalized clonic seizure in a previously healthy 50-year-old man was not pleasant, he appeared stable, and everyone involved, including Carl, agreed that we would proceed as normal and he would seek immediate fol-low-up on the ground. In the meantime, Carl would slowly drink water. Two hours later we landed as expected, and Carl walked off the plane. I left my contact information and never heard any news after that.

Weeks later, I was still going over and over the event. I began to have doubts. Had I done the right thing? Should I have recommended we land immediately? What could I have done differently? I turned to professors and medical school colleagues who gave me an array of opinions, ranging from “You absolutely did the right thing” to “I would have landed that plane immediately if there was even a remote chance of an intracranial bleed.” So I did what any evidence-based-medicine-loving student would and turned to PubMed. There I found information on the management of medical emergencies on commercial flights, and focused on a review study by Gendreau and DeJohn in the New England Journal of Medicine.

Approximately one in 35,000 airline passengers requires medical attention during a flight, with higher inci-dence on long-haul international flights. This means that every couple hundred flights, someone needs imme-diate medical evaluation, although fewer than half of in-flight medical emergencies turn out to be “serious.” Studies show that 13 percent of in-flight medical emergencies resulted in early landings. However, in situations like Dalaza’s and mine, decisions may fall to medical students, and we should be aware of several aspects of managing these cases.

First, after volunteering—and you are not obligated to do so—identify yourself and ask the patient if he or she would like your help. If the patient is unconscious, consent is presumed and Good Samaritan laws apply.
Next, just like in “regular” life, you can call for help, a fact I forgot in the moment and a simple act that re-duces early landings by up to 70 percent. The crew can contact ground-based medical teams on call 24 hours a day that specialize in aviation medicine. Think of the plane as your ward in the sky. Like in the hospital, take a focused history and physical, and develop your preliminary assessment and plan before calling your “attending” on the ground.

Third, you have access to a medical kit. The Federal Aviation Administration (FAA) mandates that these kits contain a stethoscope, sphygmomano-meter, oropharyngeal airway, bag-valve mask, IV infusion kit (with 0.9 percent normal saline), syringes and needles, gloves, automated external defibrillator, bag-valve device and a CPR mask. The medications included in the kits are nitroglycerin, diphenhydramine, dextrose, a bronchodilator inhaler, injectable epinephrine and Lidocaine with instructions. Additionally, some airlines have purchased fancier kits that far exceed FAA requirements, so taking an inventory might be useful. Further, you may have at your disposal several hundred people who can help you. Passengers may be traveling with enough prescription and over-the-counter drugs to form a virtual in-flight pharmacy. An announcement on the overhead system might elicit medications for various conditions, and even save a life. Many patients travel with plastic pillboxes, so the identity and doses of pills may not be accurate. If in doubt, consult your hand-held device’s pill identifier application which does not require a wireless signal, or use newer in-flight Wi-Fi systems. You also have a veritable in-flight interpreter service: Other passengers may volunteer to translate in the event of a language barrier.

Finally, the “horses not zebras” adage applies in the air as well as on the ground. While your typical board exam question seems to favor the patient on an international flight taking oral contraceptive pills (good guess: she has a deep-vein thrombosis), in reality, DVTs on planes are rare. Vasovagal and cardiac events are far more likely. Every day thousands of patients taking OCPs fly without incident. However, throw factor V Leiden into the picture and you might become more suspicious of a DVT in a woman with chest pain. Neurologic, ga-strointestinal, respiratory and traumatic etiologies—seatbelts, please—finish the list of common medical events on airplanes. On-board parturition? Exceedingly rare.

It is important to remember that some acute medical complaints are psychogenic. Anxiety can mimic vaso-vagal presentation. Confirm a lowered pulse rate and blood pressure before starting oxygen or informing ground medical teams that a patient is “vasovagal.” If possible, assess a patient’s comfort with flying or stressors, and reassure the passenger that he is not dying.

Several treatment recommendations are beneficial to remember. If a patient requires an IV-infusion place-ment, turbulence can be a problem. Notify the pilot of your plan even if there is only “mild chop.” Ask if she can ascend or descend for a smoother ride.

And altitude itself is an important consideration in some patients. The cabins of commercial airlines are pressurized to the equivalent of about 8,000 feet. While this is mildly noticeable to most, for passengers with cardiopulmonary conditions, the drop in oxygen carried by hemogloblin may be significant enough to reach the steep part of the curve. If oxygen is administered, the lowest possible altitude is beneficial, and the flight deck may oblige your request in an emergency.

Jeremy Faust is a third-year at Mount Sinai School of Medicine. He has a master’s degree in music composition and loves to travel.

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What Do I Do?

When your airplane-bound patient presents with particular conditions, here are some in-flight suggestions, adapted from Gendreau and DeJohn, and Newson-Smith:

  • Unresponsiveness: automated external defibrillator, oxygen, establishment of intravenous access and administration of 50 percent dextrose
  • Angina: aspirin and nitrates
  • Shortness of breath with asthma or COPD: bronchodilator
  • Vasovagal syncope: raising the legs and applying cold compresses to the forehead
  • Acute allergic reactions: diphenhydramine and, in severe cases, subcutaneous epinephrine
  • Altitude-related chest pain: increasing cabin pressure may alleviate altitude-related chest pain, shortness of breath and abdominal pain by resolving hypoxia and decreasing gas expansion
  • Acutely agitated, psychotic or violent passenger: consider sedation with a benzodiazepine, if available

Beyond the realm of emergencies, medical students often become de facto “family” medical consultants approximately five minutes after the white coat ceremony. Here are a few general points on airplane travel: First, patients with a recent history (two-three weeks) of heart attack, unstable angina, pneumothorax, a variety of invasive surgeries, cerebrovascular accidents, uncontrolled seizures, severe anemia/sickle cell crisis and pregnant women >35 weeks gestation should not fly. Second, despite rumors, data show that transmission of serious airborne infectious diseases on planes is relatively rare, likely due to the low humidity in the aircraft that makes droplet contagion less likely. That said, unsealed blankets and pillows may be infectious vectors and should be avoided, and the next generation of aircraft, like the 787 Dreamliner, will offer increased humidity for passenger comfort, though possibly increasing the risk of disease transmission.