Air Travel Emergencies

DESCRIPTION

Physicians commonly help with in-flight medical events (IME). Many IMEs fall outside a practitioner’s normal scope of practice. The aircraft environment is cramped with limited medical resources. Despite these obstacles, health care workers should be prepared to render assistance when called upon in IME settings.

EPIDEMIOLOGY

ETIOLOGY AND PATHOPHYSIOLOGY

Hypobaric hypoxia: Atmospheric pressure of oxygen drops from 160 mm Hg at sea level to 120 mm Hg at cruising altitude in a pressurized cabin. In healthy people, the drop in arterial oxygen tension is associated mean inflight oxygen saturations of 93% (range: 85 to 98).

• Gas expansion: Gases expand about 30% in flight. This can lead to a pneumothorax, sinus pressure, and tympanic membrane rupture in children with ear infections.
• Venous thromboembolism: There is an increased risk of deep vein thromboses (DVTs) on longer flights and in passengers with underlying medical conditions because of prolonged sitting, hypoxic conditions, and dehydration.
• Stress: Travelling is mentally and physically stressful, which may lead to psychiatric emergencies or acute coronary syndrome (ACS).
• Insomnia: Passengers have disrupted circadian rhythms.
• Turbulence: Turbulence is increasing due to ongoing climate changes. Motion sickness is common.
• Medication nonadherence
• Decreased access to food and drink: Vasovagal syncope may result from dehydration. Diabetics may suffer hypoglycemia.
• Low air humidity: Cabin air is <20% relative humidity, which contributes to dehydration, epistaxis, and asthma or COPD exacerbations.
• Viral infections: Parainfluenza and influenza are the most common viruses communicated by proximity. The cabin air is filtered and not infectious.

RISK FACTORS

• Recent surgery: Passengers are at risk for wound dehiscence, bowel perforation, and compartment syndrome from gas expansion.
• COPD, asthma, CHF, or coronary artery disease: Passengers may suffer from hypoxemia and may not be able to compensate appropriately.
• Recent cast placement: Passengers are at risk for compartment syndrome due to tissue edema.
• Hypercoagulability: Passengers with inherited or acquired hypercoagulable conditions, pregnancy, certain medications, heart disease, or recent surgery are at increased risk for DVTs.
• Recent scuba diving: Passengers are at risk for decompression syndromes.
• Long flights: The effects of hypoxia are cumulative and time dependent.

GENERAL PREVENTION

General guidelines:

• Travelers should discuss medication timing with their doctor and bring necessary medications and equipment onboard.
• Supplemental inflight oxygen is required for patients with a baseline PaO₂ <70 mm Hg or who are unable to walk a flight of stairs or 150 feet without becoming short of breath or experiencing angina (3)[C].

Pregnancy Considerations
Women are generally safe to fly until 36 weeks’ gestation.Pediatric Considerations
Travelers with children should bring liquid formulations of medication in allowed quantities on the plane. Children with asthma should have a rescue inhaler with spacer and facemask.
Specific guidelines:

• Avoid flying 10 to 14 days after surgery (varies by type of surgery).
• Casts may need to be bivalved if applied 24 to 48 hours before a flight.
• Avoid scuba diving 24 hours before flying.
• DVT prevention (3)[C]:
  • Adequately hydrate.
  • Stand, stretch, and exercise the legs in flight.
  • Passengers with risk factors may need compression stockings, aspirin, or anticoagulation.