Jeff: Well, this is a first! Finally at the point in my career where I can announce a disclosure, though it’s more of a potential conflict of interest than an actual disclosure, but certainly still worth noting. I currently spend some of my time working for STAT-MD - which is an airline consultation service run by the Center for Emergency Medicine and UPMC. Though I’m certainly a junior member of the team, in some sense, I’ve responded nearly 500 inflight emergencies over the last two years.

Nachi: And this definitely places you are in a particularly nice position to share some information with our listeners this month, and I’ll have some questions scattered throughout the episode for you too.

Jeff: Sounds great, so let’s dive in, starting with what I think is the most important point - qualified, active, licensed, and sober providers should volunteer to assist in the event of a medical emergency rather than decline out of fear of medicolegal concerns.

Nachi: I couldn’t agree more, so let me reiterate, please trust the evidence. And volunteer to help should you hear the call. We’ll get to this in a bit but there is little medicolegal concern and you owe it to the sick passenger to help.

Jeff: So what are the chances you are called - well, they are not particularly high, but certainly not negligible either. In 2019, of the 4 billion passengers expected to fly, there will be an estimated 60,000 medical emergencies. That means there will be about 1 emergency per every 604 flights.

Nachi: So, I fly about 4 times a month for work. At 4 times per month, over the next 12 years I can expect about one medical emergency. Already excited! Let’s start with some physiology. Cabin pressurization varies, but is typically equivalent to an altitude of 8000 feet.

Jeff: And this has a huge effect, in one study of healthy volunteers, this change in pressure resulted in a 4-10 point decrease in oxygen saturation and a 35 point drop in arterial oxygen partial pressure from 95 mm Hg to 60.

Nachi: In another study of healthy volunteers on a long haul flight, this change caused 7% of passengers to report symptoms consistent with acute altitude illness.

Jeff: Due to the principles of Boyle’s law, decreased cabin pressure also causes expansion of gases within anatomical spaces in the body such as the eye, GI tract, sinuses, middle ear, etc. This expansion can potentially threaten surrounding structures.

Nachi: So there must be guidelines for those recent post-op for flying - right?

Jeff: There certainly are, but I don’t think we need to get into the weeds on this one since nobody listening will likely be doing pre-flight screenings. I think one thing to remember here, is that though cabins are pressurized to several thousand feet, they CAN be pressurized even further if necessary. The airlines don’t do this because it takes a tremendous quantity of fuel to do so, but if pressurization will defer a diversion, this option may peak their interest. Though an anecdote, the only time I’ve ever suggested it is on a flight from someone recent post-op eye surgery who went blind midflight. We pressurized the cabin from 8000 to 4000 and then finally to sea level and his vision returned. Pretty cool stuff. But getting back to the text, next we have air quality. Only 50% of inflight air is recirculated, all of the flow is compartmentalized between sections of rows, and all the air is run through a HEPA filter. The authors note that the air is actually comparable to that of an operating room.

Nachi: Then why are people always getting sick after flying…?

Jeff: Well it’s hard to prove, but experts believe that most post flight respiratory illnesses are likely caused by exposure to fomites on high-risk surfaces of airplanes and in airports - like the trays on the seat back.

Nachi: Interesting.

Jeff: It’s also worth noting that the air is quite dry, though this is unlikely to produce any clinically significant events. Most of the dehydration that occurs is more likely due to inadequate water intake and excess caffeine and alcohol consumption depending on the time of day.

Nachi: Don’t judge. Even though it may be 8 am, some of our night shift locums friends may prefer an airport cocktail after a long week away.

Jeff: Oh I’m definitely not judging, facts only over here. Anyway, let’s move on to a little epidemiology.

Nachi: Syncope and cardiac events account for a large proportion of in-flight emergencies, with cardiac events accounting for the largest percentage of diversions.

Jeff: Gi, endocrine and respiratory emergencies follow syncope and cardiac events, with specific percentages varying based on which study you look at.

Nachi: Thankfully obstetric emergencies are relatively rare, accounting for less than 0.1% of all emergencies.

Jeff: Trauma and substance abuse related complaints have also been reported, but represent only a small percentage of inflight emergencies.

Nachi: I think that covers the main pathologies you may encounter. Next we should touch upon the actual responders. Physicians reportedly respond 44% of the time, followed by nurses at 20% and EMS providers at about 4%. Interestingly, despite physicians being there only 44% of the time, they were involved in the care for over 70% of diversions.

Jeff: It might seem crazy, but that’s definitely my experience. Many physicians, especially non-ED physicians are not familiar with caring for the acutely ill. Additionally, most physicians are very uncomfortable actually witnessing someone syncopize and then immediately checking vitals and finding the passenger to be bradycardic and hypotensive as is the case with many patients immediately after a vasovagal syncopal episode. I cannot tell you how many times we get called by pilots considering diversion based on a physician’s request only to have the symptoms completely resolve in just 10 minutes. Be patient, this is a common in flight pathology.

Nachi: Your experience has not failed you - data from your own group showed that 31% of cases resolved before arrival. Even in cases where EMS was requested, patients were only transported 37% of the time and of those, only 8% were actually admitted for further work up. Death is also a very rare phenomenon, occurring in only 0.3% of cases.

Jeff: Alright, so let’s move onto the actual logistics of responding. Each airline has its own protocols and policies with respect to medical responders - some will require credentials, others may not. In some instances, you may be the first responder, in others, the flight crew may have already been in contact with their ground based medical control.

Nachi: In terms of supplies, the FAA requires an emergency medical kit and an AED on all commercial flights. These kits cannot be opened without direction from a medical professional on the ground or on board.

Jeff: And while airlines may add additional drugs at their discretion, the FAA mandates certain supplies. You can remember these supplies by thinking of the 5 A’s - asthma, allergy, altered mental status, ACS, and ACLS. The 5 As should help you remember the bronchodilators, epinephrine, antihistamine, dextrose, nitroglycerine, aspirin, and lidocaine as the one antiarrhythmic available. Of course, there are also gloves, an IV start kit, and a few other basic supplies.

Nachi: AEDs are also required and have been since 2001 and amazingly when a shock was delivered in flight, 40% survived to hospital discharge with a good outcome.

Jeff: Just as on the ground, shockable rhythms do well with good BLS care. And lastly, airlines also have a portable oxygen tank in addition to the emergency oxygen that is stored in the event of cabin depressurization. The exact quantity varies, but portable cylinders are certainly available.

Nachi: So next we have to talk about a topic that I’m sure many of you have wondered about - what are the medico-legal risks of intervening?

Jeff: As with most incidents of concern over medico-legal risk, we really just shouldn’t be too concerned over the potential legal ramifications. Though we’ll get into specifics, the short answer is that you should definitely volunteer your services - there are lots of protections in place with a paucity of case reports of legal actions against medical volunteers who volunteers in flight.

Nachi: Perhaps most importantly, remember that ultimately the captain is in charge and you are functioning in a strict advisory capacity. Remember that most airlines can handle most emergencies with their ground based medical control, their typical staff, and predefined protocols - you are an added bonus.

Jeff: For many ED providers, functioning as a consultant will be unfamiliar.

Nachi: If I’m a consultant, I’m going to demand a WBC before seeing the patient, as I’m fairly certain that’s rule number 1 in consultant school...

Jeff: It’s actually rule #12, now get out of your seat and come see the patient…. But back to medicolegal issues. In the US, health care professions are protected by the good Samaritan law and the 1998 federal aviation medical assistance act.

Nachi: The Good Samaritan law provides legal protection to medical providers who perform their services in response to medical emergencies outside of the hospital. The exact verbiage of the law differs from state to state, but all 50 states have some version of it in their legislation.

Jeff: Similarly the aviation medical assistance act applies to “medically qualified individuals and offers broad medico-legal protection to the airlines in the event that a medical volunteer is accused of malpractice as well as to medical providers who respond to an in-flight emergency.”

Nachi: More specifically, the act states that “...an individual shall not be liable for damages 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.”

Jeff: That’s a bit of a mouth full to get out. But basically, you need to remember that the AMAA protects you from everything shy of gross negligence. Because of this, there have been no reports to date of a medical professional falling below that standard.

Nachi: There is one caveat to all of this though: don’t forget about your own mental status - for example if you have taken any sleeping aids or had any alcoholic drinks. Though this may not preclude you completely from rendering care, do so only with extreme caution.

Jeff: And I don’t think we were clear enough about this up front. Up until this point we have mostly talked about US based flights. Flights run by International airlines are a somewhat different ball game for a number of reasons. First, medication kits will vary widely. Many will carry medications similar to those mandated by the FDA, but there certainly is no international standard. Next, the availability of ground based medical consultation is similarly widely variable, with many in the middle east contracting for this service and almost no airlines in Africa offering such services.

Nachi: And lastly, with respect to legal risk - the international laws also vary widely. According to French law, for example, a French physician who does not volunteer may be committing willful negligence. Similar laws exist in Germany, Australia, and Canada. However proving you were there and refused to provide care would be quite difficult. And lastly, it’s unclear how to determine which countries’ laws apply when - for example, is it the sending country’s laws, the receiving country’s laws, or the country whose airspace you are currently in?

Jeff: All excellent points. Next, we are moving to my favorite topic of the article - diversion. This is a tremendously complicated topic and I think the authors handled it quite well. Remember, the decision to divert is multifactorial and you are only there to communicate your medical opinion about the passenger - leave the decision for diversion up to the flight crew. I cannot stress this enough. Getting on the radio with the pilot and ground based medical control and demanding a diversion is often very unhelpful and simply not the right approach and can really be quite costly.

Nachi: All of this is so interesting. I can’t believe you do this and divert planes.... Can you go into a bit more detail about everything the pilot considers when they are deciding to divert?

Jeff: So there’s quite a bit, but I can touch on some of the main considerations. First, you have to consider the medical needs of the passenger - can he or she be temporized to get to the destination? Is there a suitable airport for diversion with an accessible local hospital with the required resources? Logistically, you need to find an airport that can not only safely accommodate the plane you are on but also one in which the airline can refuel and guarantee that the passengers and crew are safe. Remember, if you are on an A380, there are only so many airports with runways long enough for a safe landing. Fun fact: planes also take off heavy - with tons of fuel that will be burned prior to landing. Say you were to take off from London, bound for the US. To turn around and land back at London Heathrow, you may have to literally dump thousands of gallons of fuel to get the plane to a safe weight for landing. Alternatively, you may have to fly in circles for some time to burn fuel off in planes that cannot dump. A heavy landing necessitates a thorough maintenance overhaul of the landing gear and can cost the airlines not only money but significant time, which is equally as valuable.

Nachi: Speaking of cost - while exact costs are unknown, one airline estimates that the cost can be as high as $600,000 - we are not dealing with small numbers here...

Jeff: No definitely not. That’s why it’s so frustrating when medical volunteers demand the plane divert without talking through the medical scenario with the crew and ground based control - often temporizing measures are adequate.

Nachi: And we alluded to this earlier - Physicians advise diversion more frequently at 9% of the time followed by EMS providers and nurses. When the airlines are left to their own means, they divert at rates roughly half that - just 5% of the time. At half a million dollars for some diversions, and an overall very low level of morbidity and mortality, a 50% reduction amounts to massive savings for possibly no clinical difference.

Jeff: I can’t stress this enough - you are a consultant, helping the captain and the ground based medical control to come to most appropriate plan of action. When your advice causes the airlines to deviate from their standard protocols, that’s where they potentially run into trouble.

Nachi: There are just two controversies to discuss this month and I actually think they are extremely pertinent. The first one relates to using personal medication or medications from other passengers. Given the relative paucity of medications in most airline medical kits, it may occur to you that someone else may have a helpful medication on board. While there is no strict rule against this, it could result in an increased level of scrutiny if there is an adverse event. So consider this a last resort.

Jeff: The next controversy to discuss is the issue of gifts. There is a widespread belief that accepting gifts from the airlines would void legal protections. To date, there is ample airline-based data to suggest that medical providers’ legal protections are not negated in the event that the airlines wanted to reward a medical volunteer. Additionally, there are no reported cases of providers losing legal protection for receiving compensation for their services in flight.

Nachi: Interestingly, some international carriers even offer points or other bonuses for registering as a medical volunteer. While I’m hesitant to call this controversy a myth, it seems like there isn’t much evidence to support it.

Jeff: Agreed, don’t expect a gift, but if you do receive one, you can keep it and enjoy it without concern for your legal protections.

Nachi: Alright so that wraps up the new material for this special edition of EMplify - let’s close out with some key points and clinical pearls.

Jeff: Aircraft cabins are typically pressurized to about 8000 ft, resulting in a 4-10 point drop in oxygen saturation in healthy adults as well myalgias, fatigue, and generalized discomfort on long haul flights.

Nachi: Only 50% of the cabin air is recirculated. When recirculated, it is subjected to HEPA filtration, which is adequate to prevent infection by airborne pathogens but not the infectious respiratory viruses, which are spread by droplets.

Jeff: Dehydration on long flights is likely due to inadequate water intake and the increased use of diuretics such as caffeine and alcohol.

Nachi: There is about 1 in-flight emergency per 11,000 passengers or 1 in 604 flights. Syncope and cardiac events are most common followed by GI, respiratory, and neurologic events.

Jeff: Most in-flight emergencies are minor. When EMS is requested upon arrival, roughly 1/3rd are transported and less than 10% are admitted, with mortality estimated at 0.3% of cases.

Nachi: AEDs are required on all US-based flights.

Jeff: Airlines have a limited supply of supplemental oxygen for use in medical emergencies in addition to that provided to the entire plane in the event the cabin becomes depressurized

Nachi: All US airlines have some form of ground-based medical assistance. Ultimately any decisions are the responsibility of the pilot in command – medical volunteers function in a strictly advisory capacity.

Jeff: Medical volunteers are protected by both the Good Samaritan law and the 1998 Aviation Medical Assistance Act.

Nachi: The Aviation Medical Assistance Act protects medically qualified individuals, unless they are guilty of gross negligence or willful misconduct.

Jeff: International laws and protections vary widely. In some European countries, for a physician to not offer their services during an in-flight emergency may constitute willful negligence.

Nachi: The decision to divert is multifactorial and can cost as much as $600,000 in some circumstances.

Jeff: When physicians and EMS providers respond to in-flight emergencies, diversion rates are nearly double that of when the airlines work solely with their ground based support, increasing diversion events from 5% to 9%.

Nachi: It is largely a myth that accepting any gift or payment after responding to an in-flight emergency would void your legal protections; the AMAA has no language regarding compensation and to date there are no such reported cases of lost legal protection.

Jeff: And that’s the end of this months episode of EMplify: Assisting With Air Travel Medical Emergencies. This also marks the end of our run as your hosts. Over the past 3 years, we’ve thoroughly enjoyed hosting EMplify and having the unique opportunity to share high quality evidence based medicine with you all. As health care continues to move towards a quality over quantity paradigm, understanding evidence based practice will be increasingly more important.

Nachi: We thank you all for giving us your ears and your time to help hone your clinical practice. Naturally, a big thanks also goes out to all of the contrubutors to Emergency Medicine Practice -- authors, peer reviewers, and of course the kind and thoughtful staff at EB Medicine.

Jeff: We have no doubt that Dr. Ashoo, who will be taking over, will keep you on the edge of your seat as he brings new material to you. Couldn’t be more excited to have him as our successor.

Nachi: As always, additional materials are available on our website for Emergency Medicine Practice subscribers. If you’re not a subscriber, consider joining today. You can find out more at ebmedicine.net/subscribe. Subscribers get in-depth articles on hundreds of emergency medicine topics, concise summaries of the articles, calculators and risk scores, and CME credit. You’ll also get enhanced access to the podcast, including any images and tables mentioned. PA’s and NP’s - make sure to use the code APP4 at checkout to save 50%.

Jeff: The [DING SOUND] you heard throughout the episode corresponds to the answers to the CME questions. Lastly, be sure to find us on iTunes and rate us or leave comments there. You can also email us directly at EMplify@ebmedicine.net.