EMS Flight Stressors and Corrective Action

Issues of Concern

Although the medical supplies on an aircraft vary based on passenger capacity and flight duration, the International Civil Aviation Organization (ICAO) and the Federal Aviation Administration (FAA) have established both recommended and mandatory lists to ensure adequate provisions. Required onboard supplies include first aid equipment and medications accessible to anyone assisting a passenger with a medical emergency. FAA-mandated medications include nonnarcotic analgesics, antihistamines, aspirin, atropine, dextrose 50%, epinephrine (1:10,000 and 1:1,000), albuterol, hydrocortisone, diphenhydramine (oral and injectable), intravenous lidocaine, and nitroglycerin.

Each kit also contains gloves, a stethoscope, a sphygmomanometer, CPR masks, bag-valve masks, oropharyngeal airways, intravenous start kits, 500 mL of normal saline, needles, and syringes. ICAO further recommends including urinary catheter kits and tracheal intubation supplies.[8]

Psychological Stress

Flight can be stressful for anyone, but individuals with an underlying psychiatric condition or a fear of flying are particularly susceptible to acute agitation and anxiety during travel.[9] This stress is often managed with guided behavioral calming techniques, reassurance, and, if necessary, standard doses of first-line agents such as haloperidol, midazolam, and diazepam.[10]

When assisting a passenger experiencing psychological distress, organic causes such as hypoglycemia, intoxication, and trauma should be considered. Supplemental oxygen may be offered if appropriate. Reviewing the individual's current medications and assessing the need for an as-needed (or pro re nata or PRN) dose can help guide management. If additional intervention is required, the emergency medical bag may contain an anxiolytic, such as haloperidol, as recommended by the ICAO. Patients who do not respond to these measures may require ketamine or propofol, necessitating immediate aircraft diversion and continuous monitoring to ensure flight safety.[11]

Barotrauma

Changes in cabin pressure during ascent, descent, or unexpected variations in level flight can cause pain due to trapped gas in the intestinal tract, teeth, sinuses, or middle ear. Tympanic distention during descent is generally well tolerated by most healthy individuals. Adults can relieve pressure using the Valsalva maneuver, while the Centers for Disease Control and Prevention (CDC) Yellow Book recommends that children chew gum or swallow and that infants be offered nursing or bottles to alleviate discomfort.

However, in the presence of nasal or sinus congestion, these measures may be insufficient, increasing the risk of tympanic perforation and sinus barotrauma. A sudden relief of intense ear pain may indicate perforation, warranting follow-up with a primary care physician and possibly an otolaryngologist. Similar acute, localized pain may occur in the sinuses, teeth, or intestines and should be evaluated by a physician after the flight.[12]

Altered Mental Status

Insidious hypoxia can impair central nervous system function, leading to a range of neurological symptoms. Hypoxic vasoconstriction may severely affect other organ systems, increasing the risk of pulmonary edema and reducing cardiac output, which can result in congestive heart failure (CHF) or myocardial infarction. Other potential causes of altered mental status include stroke, intoxication, infection, circadian rhythm dysregulation, and metabolic disorders such as hypoglycemia.

While airborne, these conditions may manifest as confusion, altered mental status, or loss of consciousness. Poor oxygenation should be considered a potential cause, and the condition of other crew members and passengers should be assessed. If multiple individuals are affected, the FAA recommends that responders first secure their own oxygen supply before assisting others. If only 1 person is impacted, respiratory compromise should be suspected. Administering supplemental oxygen and reassessing the individual as the aircraft descends to a lower altitude may be appropriate.[13] If the airway is protected, a small, sugar-containing snack may be offered while accessing the in-flight emergency medication bag to administer glucose or a glucose-containing fluid.

Myocardial Infarction

High-altitude environments, defined as elevations above 2,500 m, present physiological challenges due to reduced atmospheric pressure and oxygen availability. Millions of people ascend to high-altitude locations daily, facilitated by modern air travel, with mountain regions covering 24% of Earth's surface. The body adapts through mechanisms such as increased cardiac output and erythropoiesis, but these responses may become maladaptive in individuals with coronary artery disease (CAD). While some studies suggest that patients with stable CAD tolerate moderate altitudes, others indicate an increased risk of ischemic events, emphasizing the need for careful risk assessment, particularly in people with prior myocardial infarction or impaired left ventricular function.[14]

Myocardial infarction may develop in individuals vulnerable to increased sympathetic tone and gradual hypoxia, leading to vasoconstriction.[15] If myocardial infarction is suspected, providers must administer oxygen and request the medical bag from the flight crew. If possible, responders must determine whether the individual is on anticoagulation therapy and obtain a blood pressure measurement. When appropriate and available, the patient should be offered aspirin and nitroglycerin. The crew should also be advised to consider diverting to the nearest airport with hospital access. Symptoms may improve upon returning to ground-level conditions.

Air travel should be undertaken with caution in individuals with a history of myocardial infarction, given their susceptibility to cardiovascular instability at high altitudes. Risk stratification guidelines by the British Cardiovascular Society categorize these patients into 3 groups.

Very low-risk patients include adults younger than 65 with a 1st cardiac event, successful reperfusion, left ventricular ejection fraction (LVEF) over 45%, no complications, and no pending cardiac procedures. These individuals can fly 3 days after the event. Low- to medium-risk patients have LVEF between 40% and 45%, no heart failure symptoms, and no evidence of inducible ischemia or arrhythmia. These individuals can travel 10 days postevent. High-risk patients have LVEF below 40%, symptomatic heart failure, or pending revascularization or device therapy. These individuals should be advised to delay high-altitude exposure for at least 6 weeks.

Studies indicate that stable post-myocardial infarction patients can tolerate air travel, though some may experience asymptomatic hypoxia requiring oxygen supplementation or angina relieved with nitroglycerin. Patients with CAD should follow specific precautions, including medication adherence, proper hydration, acclimatization, and oxygen access when necessary.

Presyncope/Syncope

As the most commonly reported in-flight medical emergency, this condition may present with diaphoresis, pallor, and mild alterations in mental status. Initial findings often include bradycardia and hypotension. When feasible, the patient should be placed in the Trendelenburg position (lying supine with the feet elevated), which may require utilizing the galley or aisle.

Supplemental oxygen may aid recovery, and a fingerstick glucose test can help guide diagnosis. Persistent hypotension may respond to oral or intravenous fluid administration. If symptoms do not resolve after 15 to 30 minutes of intervention, contacting ground-based medical support and advising aircraft diversion should be considered, as a more serious underlying condition may be present.

Shortness of Breath

Asthma, chronic obstructive pulmonary disease (COPD), and pulmonary hypertension can worsen due to reduced oxygen concentrations, triggering a heightened sympathetic response that may present as hyperventilation, tachycardia, and chest pain. Individuals with chronic obstructive pulmonary disease, who typically have lower baseline oxygen levels, should be advised to travel with supplemental oxygen to mitigate the risk of hypoxia while airborne.

Recent severe viral respiratory illnesses should also be considered, as up to 20% of patients may experience reduced diffusing capacity for as long as 100 days following hospitalization.[16] If symptoms arise during flight, initial management includes supplemental oxygen and the use of the patient’s own inhaled bronchodilator, such as albuterol. The in-flight medical emergency kit stethoscope can assist in evaluating for decreased breath sounds, which may indicate pneumothorax. If pneumothorax is suspected, needle decompression should be considered as the aircraft descends to a lower altitude.

For symptoms more indicative of an asthma exacerbation, bronchodilator treatment may be repeated every 5 to 15 minutes as needed. If symptoms persist, intramuscular epinephrine (1:1,000) at 0.01 mg/kg, up to a maximum dose of 0.5 mg, may be administered. In severe cases, aircraft diversion to the nearest hospital-equipped airfield is warranted.

Exposures

Individuals prone to allergic reactions, particularly those with heightened sensitivity to irritants and allergens, may experience symptoms during flight, including respiratory distress, dermatitis, and abdominal pain. Anaphylaxis should be considered in individuals with severe symptoms.

For passengers with a known history of anaphylaxis, preventive measures include requesting food buffer zones, allergen-free meals, and wiping down tray tables. Crew announcements may be necessary to inform other passengers and encourage avoidance of specific allergens, such as peanuts or sesame.

If anaphylaxis is suspected, responders must administer oxygen and promptly access epinephrine from both the patient’s supply and the in-flight medical bag, repeating every 15 minutes as needed. Oral or injectable corticosteroids and antihistamines may be considered during descent. In severe cases, aircraft diversion to the nearest hospital-equipped airfield should be initiated.

Motion Sickness

Nausea and vomiting resulting from sensory conflict or vestibular disturbance, though uncomfortable, are rarely life-threatening during flight. Motion sickness may be exacerbated by environmental factors such as heat, vibration, turbulence, or task saturation, as well as by an atypical orientation relative to the direction of travel.

Mitigating these factors can help alleviate symptoms. Offering cool, ventilated air or a cool compress, relocating the individual to a forward seat or an area over the wings to minimize vibration, and ensuring they remain in a forward-facing position with a view of the direction of travel may be beneficial. If the individual is engaged in in-flight responsibilities, a temporary break may help.[17] Adjusting altitude to reduce turbulence can also be considered when feasible.

If the patient does not have antiemetic medication available, diphenhydramine from the onboard medical kit may provide relief, and administration of 500 mL of intravenous normal saline can help prevent dehydration. While motion sickness is the most common cause of nausea in flight, infectious etiologies such as gastroenteritis or food poisoning should be considered. If suspected, isolating the affected individual when possible and monitoring for symptoms in other passengers is advised.[18]

Fatigue and Musculoskeletal Strain

Vibration, dehydration from low cabin humidity, and circadian dysregulation, particularly jet lag associated with crossing multiple time zones, can contribute to daytime fatigue, poor sleep, and headaches that may persist for 3 to 4 days.[19] Alleviating these symptoms begins with the cessation of flight-related stressors and adequate hydration. The primary regulator of the circadian system is timed light exposure, which helps align the body’s internal clock with the local day-night cycle. Retiming strategies may be combined with scheduled meals, exercise, and short naps to shorten symptom duration.

Pharmacologic interventions may further support circadian adjustment. Stimulants such as caffeine or other "go pills" can enhance wakefulness, while melatonin supplementation may facilitate sleep onset.[20] However, the use of other sleep aids should be carefully evaluated, as certain medications can affect sleep quality or cause adverse effects such as slowed reaction times and impaired situational awareness, posing risks for individuals operating equipment or vehicles.[21]

Some studies cite musculoskeletal strain as a significant contributor to poor sleep and high psychological stress levels during long flights. Crew members can help alleviate musculoskeletal strain by encouraging passengers to perform simple in-seat exercises, such as foot pumps, neck rolls, and shoulder rolls, while also advising them on posture and hydration.[22] Passengers can take proactive measures by strengthening key muscle groups before travel, using ergonomic accessories, and selecting seats with more legroom when possible. Airlines can enhance passenger comfort by optimizing seat design, increasing legroom in economy class, and offering premium seating options on long-haul flights. (Source: Ng and Henderson, 2021)

High Gravitational Exposures

Gravitational forces along the z-axis (head to foot), encountered primarily in high-performance military aircraft during abrupt maneuvers, can lead to acute loss of consciousness if the “anti-G straining maneuver” (AGSM) is not performed effectively, regardless of the aviator's physical condition.[23] This phenomenon occurs due to the pooling of blood in the lower extremities, resulting in cerebral hypoperfusion and hypoxia. Initial symptoms include a “gray-out” of the visual field, followed by complete loss of consciousness lasting several seconds.

Some individuals may also experience transient muscle spasms before regaining awareness, though purposeful movement may remain impaired for up to 30 seconds even after G-force exposure ends. This condition, known as G-induced loss of consciousness (GLOC), resolves once normal gravitational conditions are restored, allowing cerebral perfusion to return to baseline.

The mission should be aborted following an in-flight GLOC event, and the aviator must return to the home station for medical evaluation. Standard postincident protocols include a thorough review of 72-hour and 7-day histories, along with blood and urine testing, in accordance with military guidelines to assess for contributing factors.

Special Conditions

Some individuals are at higher risk for decompression sickness (DCS) when flying after diving due to factors influencing inert gas uptake and elimination. People with a prior history of DCS, a patent foramen ovale, poor hydration, high adipose tissue content, or a tendency to form vascular bubbles are particularly susceptible. In these cases, nitrogen elimination is altered, leading to a higher likelihood of bubble formation in the bloodstream, ischemia, and inflammatory responses when exposed to reduced barometric pressure during flight.[24]

To mitigate this risk, extended preflight surface intervals beyond the standard 24 hours or preflight oxygen administration may be recommended. Studies indicate that divers who adhere to these precautions experience significantly lower rates of postflight DCS. Ultrasound studies have shown no detectable bubbles in most individuals after a sufficient interval. Conversely, individuals who neglect these recommendations, particularly those with undiagnosed patent foramen ovales, may have a substantially higher incidence of postflight DCS. In previously affected divers, the risk of recurrence can exceed 50%.[25]

Diabetes mellitus requires continuous medical care to prevent complications and manage its impact on daily life, including activities such as aviation. Pilots with this condition, particularly those using sulfonylureas or insulin, face unique challenges due to flight conditions like hypobaric pressure, which may alter glucose measurements and increase the risk of hypoglycemia or hyperglycemia.

Strict blood glucose monitoring protocols and appropriate corrective actions are necessary to ensure flight safety, as severe glucose fluctuations can impair cognitive function and decision-making. While pilots with well-controlled diabetes may obtain flight certification, their ability to detect and manage low glucose levels is critical. Guidelines have been established to help pilots with diabetes mellitus maintain safe blood glucose levels throughout flights, including structured monitoring and intervention protocols.

Passengers with diabetes mellitus can travel safely by air if they maintain stable glycemic control and adhere to essential precautions. Medications, including insulin and oral antidiabetics, should be carried in hand luggage, and passengers should inform airlines about medical supplies and insulin pumps in advance. Continuous glucose monitors (CGMs) and insulin pumps should not pass through x-ray machines or full-body scanners, as electromagnetic interactions and pressure changes during flight may alter insulin delivery, potentially causing hypoglycemia or hyperglycemia.

Adjustments to insulin regimens may be necessary depending on time zone shifts, with longer westward travel often requiring additional insulin doses and eastward travel potentially necessitating dose reductions. Frequent glucose monitoring and preparedness with emergency carbohydrates, glucagon, and proper storage of insulin are crucial to ensuring safe air travel.[26]

Clinical Significance

Passengers with preexisting health conditions should be advised to undergo a preflight medical evaluation to ensure safe travel. Carrying essential medications in hand luggage and informing the airline of specific needs, such as supplemental oxygen or special seating arrangements, can help prevent complications. Flight crews and airlines can enhance passengers' flight experience by maintaining high-quality air filtration, regulating cabin temperature, and improving seating ergonomics to minimize discomfort. Adequate hydration and entertainment further reduce in-flight stress.

Flight medicine focuses on understanding how normal physiology is altered by the stresses of flight and implementing mitigation strategies for individuals most vulnerable to these effects. The constraints of limited resources and confined environments compound these challenges.

When a physiologic event occurs in flight requiring medical intervention for stabilization, comfort, or safety, the Aviation Medical Assistance Act provides legal protection to those in the U.S. who volunteer to assist the flight crew. Initial stabilization often involves administering oxygen, utilizing the CPR-trained flight crew, and employing standard onboard medical supplies. Additionally, forming a differential diagnosis and advising the crew on whether an emergency diversion is warranted are key aspects of in-flight medical decision-making.