In-flight Medical Events

Educational Objectives

The goal of this program is to improve the management of in-flight medical emergencies. After hearing and assimilating this program, the clinician will be better able to:

1. Recognize common in-flight medical emergencies and available resources to manage them.

2. Determine fitness to fly for patients with medical conditions.

Summary

Introduction: epidemiology — prevalence of in-flight medical events 24 to 130 per 1 million passengers (>1000 daily); Communication Center at University of Pittsburgh — staffed 24 hr, 7 days per week by medical coordinators, communications specialists, and command physicians from department of emergency medicine; among other services, provides medical consultations for ≈20 international and domestic airlines; in 2018, performed >27,000 airline consultations; study by Peterson et al (2013) found prevalence of medical event ≈1 per 604 flights; participants in in-flight medical event — ill passenger; flight attendants; on-board health care volunteer; pilot; radio communication center; airline dispatch center and ground-based medical support (GBMS) sometime involved

In-flight resources: availability of resources and personnel should be considered in management; physicians present on 48% of flights, nurses on 25%, and emergency medical technician or paramedic on ≈4%; lack of medical personnel or volunteer occurs in ≈23% of flights; emergency medical kit — contents vary by airline; automated external defibrillator (AED) required on aircraft with >50 seats; equipment required by Federal Aviation Administration (FAA) include blood pressure cuff, stethoscope, equipment for inserting intravenous (IV) line (eg, needles, IV catheters, tourniquet, IV tubing, alcohol), equipment for management of airway (eg, bag-valve mask, oral airway), and medications; required medications are acetaminophen, aspirin, nitroglycerine tablets, albuterol inhaler, diphenhydramine (eg, Benadryl), epinephrine 1 to 1000 (for allergic reactions) and 1 to 10,000 (for cardiac events) solutions, atropine, and lidocaine; dextrose 50% typically supplied; medications sometimes added include calcium chloride, diazepam (Valium), dimenhydrinate (eg, Dramamine, Driminate, Triptone), haloperidol, hydrocortisone, furosemide (Diaqua, Lasix, Lo-Aqua), lorazepam, meclizine, methylprednisolone, morphine, metoprolol, naloxone, ondansetron, promethazine, and sodium bicarbonate; equipment sometimes added include glucometer, cardiac monitor, laryngoscope, endotracheal tube, tourniquet for control of bleeding, burn dressings, Steri-Strips, scalpel

Liability of volunteering: Aviation Medical Assistance Act of 1998 (“Good Samaritan Law”) frees medical volunteers from liability, provided that care does not egregiously violate standards of care; also frees airline from liability if it believes that volunteer is medical provider; legal protection may be revoked if compensation requested

Diversion of aircraft: decision based on medical event; authority to divert limited to captain and dispatcher; medical volunteers and GBMS serve as consultants; location of diversion depends on size and type of aircraft, weather, and condition of patient; resources suitable for patient at diversion destination and capability of airport to accommodate aircraft must be considered; weight of full tank of fuel complicates landing shortly after takeoff; cost of diversion varies widely; financial disincentives of diversion have promoted development of GBMS; role GBMS to recommend diversion or in-flight management

Types of in-flight emergencies: syncope or near-syncope most common (account for ≥33%); other events include gastrointestinal, respiratory, cardiovascular, neurologic, trauma, psychiatric, intoxication, allergic reactions, and obstetric; cardiac arrests uncommon (available modalities of treatment include AED, cardiopulmonary resuscitation, and drugs); syncope and near-syncope events — commonly caused by dehydration; signs include unresponsiveness, pallor, diaphoresis, hypotension, and bradycardia; stabilization usually achieved by positioning patient in supine position and raising legs; associated myoclonic jerking can be misinterpreted as seizure (unlikely if duration ≤5 sec); postictal state suggests seizure; respiratory events — aircraft noise precludes auscultation of lung sounds; obtain cardiopulmonary history; available medications include oxygen, albuterol, and furosemide; gastrointestinal events — nausea, vomiting, and abdominal pain common; medications that can serve as antiemetic agents include meclizine, promethazine, dimenhydrinate, and ondansetron; abdominal pain should raise concern for surgical emergency; chest pain — obtain thorough history; medications available for cardiac events include aspirin, nitroglycerine, and oxygen; high suspicion for cardiac emergency may require diversion

Outcomes: rate of diversion ≈4.5%; use of GBMS decreases rate to ≈2%; rate of transport to hospital by EMS 26% (9% of which admitted to hospital); rate of death ≈0.3%

Medical emergencies at high altitude: case study 1 – 60-yr-old man ran through terminal to catch connecting flight; upon arrival at gate, reports chest pain and shortness of breath; case study 2 – 70-yr-old woman with history of chronic obstructive pulmonary disease (COPD) and nighttime use of oxygen requests permission to fly; case study 3 – 24-yr-old man involved in accident on all-terrain vehicle; injuries included pneumothorax; chest tube removed 1 day before flight; case study 4 – 30-yr-old woman returning from vacation in Bahamas; reported scuba diving 12 hr before flight; experiences chest pain during flight

Physiology: high altitude characterized by lower barometric pressure and partial pressure of oxygen and expansion of gases; individual with PaO2 of 159 mm Hg at sea level decreases to ≈132 mm Hg at 5000 ft and 109 mm Hg at 10,000 ft; oxygen saturation of 98% at sea level decreases to 87% at 10,000 and 60% at 22,000 ft; methods to increase PaO2 include increasing FiO2 or descending to lower altitude; majority of aircraft cabins pressurized to 6000 to 8000 ft; COPD — decreased oxygen saturation on commercial aircraft can result in shortness of breath; treatment includes administration of portable oxygen; on-board portable oxygen units designated for use by flight crew, but can be used for passengers requiring oxygen; pneumothorax — size increases with higher elevation; can increase 25% to 30% at 6000 ft to 8000 ft; decompression sickness — volume of gas in solution proportional to pressure of gas; nitrogen dissolved in blood increases during scuba diving; subsequent relocation to high altitudes may result in precipitation of nitrogen and air embolism; embolism to brain can cause sudden loss of consciousness; microemboli to joints cause pain (“bends”); FAA recommends no flying within 12 hr for individuals diving to depth of 30 ft and within 24 hr for any dive requiring decompression equipment

Management: screen patients at risk before flights; consult medical manual of International Air Transport Association to determine fitness to fly; case study 1 — in absence of history of coronary artery disease and if symptoms resolve with rest, flying likely safe; in patient with history of coronary artery stents and persistent symptoms, flying not recommended; evaluation by local EMS provide data that may be used by GBMS; case study 2 — unlikely to tolerate high altitude given need for nighttime oxygen; FAA prohibits personal oxygen tanks on aircraft; oxygen concentrators permissible (require FAA approval); devices must be powered by battery (battery life needs to be 150% of length of flight); flow of oxygen concentrators limited to ≤4 L/min; patients requiring 6 L/min unable to fly (oxygen tanks on aircraft limited to 4 L/min); case study 3 — confirm resolution of pneumothorax before flight; case study 4 — hyperbaric oxygen treatment of choice

Readings

Aerospace Medical Association Medical Guidelines Task Force: Medical Guidelines for Airline Travel, 2nd ed. Aviat Space Environ Med 2003 May;74(5 Suppl):A1-19; Bettes TN and McKenas DK: Medical advice for commercial air travelers. Am Fam Physician 1999 Sep 1;60(3):801-8, 810; Ergan B et al: Should I stay or should I go? COPD and air travel. Eur Respir Rev 2018 Jun 13;27(148); Epstein CR et al: Frequency and clinical spectrum of in-flight medical incidents during domestic and international flights. Anaesth Intensive Care 2019 Jan;47(1):16-22; Martin-Gill C et al: In-Flight medical emergencies: a review. JAMA 2018 Dec 25;320(24):2580-2590; Peterson DC et al: Outcomes of medical emergencies on commercial airline flights. N Engl J Med 2013 May 30;368(22):2075-83; Verjee MA et al: Medical issues in flight and updating the emergency medical kit. Open Access Emerg Med 2018 Apr 30;10:47-51.

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest.

Acknowledgements

Dr. Doyle was recorded at the Update in Internal Medicine 2019: Advances Changing Practice, presented by the University of Pittsburgh School of Medicine, Center for Continuing Education in the Health Sciences, and held October 10-11, 2019 in Pittsburgh, PA. For information on other CME conferences presented by the University of Pittsburgh School of Medicine, please visit https://cce.upmc.com/. The Audio Digest Foundation thanks the speakers and sponsors for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

Lecture ID:

IM671801

Qualifies for:

ABIM MOC

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.