When is a patient with Lower Respiratory Tract Infection (LRTI) and wheeze, indicating probable obstructive airway disease, but not requiring oxygen, fit to fly?

Fitness to Fly After LRTI with Wheeze and Probable Obstructive Airway Disease

Patients with LRTI and wheeze suggesting obstructive airway disease who were not hospitalized can fly once clinically stable, but must undergo pre-flight oxygen saturation assessment to determine if supplemental oxygen is needed during flight. 1, 2

Critical Timing Consideration

If the patient required hospitalization for this acute respiratory illness, they must wait at least 6 weeks after hospital discharge before flying. 1, 2 This is a firm British Thoracic Society recommendation that applies to all patients discharged for acute respiratory illness, regardless of current oxygen requirements. 2

For patients managed as outpatients who never required hospitalization, the timing is more flexible and depends on clinical stability and oxygen saturation assessment. 2

Pre-Flight Assessment Algorithm

All patients with probable obstructive airway disease recovering from LRTI require formal assessment before flying, which includes: 1, 2

• Measurement of resting oxygen saturation (SpO₂) by pulse oximetry at sea level, taken from a warm ear or finger after allowing the oximeter to stabilize 1
• History and examination focusing on cardiorespiratory symptoms, dyspnea, and any previous flying experience 1
• Spirometric testing to assess severity of obstructive disease 1, 2

Decision Based on Oxygen Saturation

The fitness to fly determination follows a clear algorithm based on sea level SpO₂: 1, 2

SpO₂ >95%:

• Patient is fit to fly without supplemental oxygen 1, 2
• No further testing required 2

SpO₂ 92-95% without additional risk factors:

• Patient is fit to fly without supplemental oxygen 1, 2

SpO₂ 92-95% with additional risk factors:

• Hypoxic challenge testing is required before determining fitness to fly 1, 2
• Additional risk factors include: FEV₁ <50% predicted, hypercapnia, cerebrovascular or cardiac disease, or being within 6 weeks of discharge for acute respiratory illness 1

SpO₂ <92%:

• Patient requires in-flight supplemental oxygen at 2 L/min via nasal cannulae 1, 2
• Patient can fly but must arrange oxygen with airline in advance 1

Essential In-Flight Precautions

Once cleared to fly, patients with obstructive airway disease must: 1, 2

• Carry all preventative and relieving inhalers in hand luggage (not checked baggage) 1, 2
• Avoid excess alcohol before and during flight, as this can worsen hypoxemia 1, 2
• Remain mobile during flight if not receiving oxygen to reduce thromboembolism risk 1, 2
• Be aware that walking without supplemental oxygen may worsen hypoxemia; consider using oxygen while moving about the cabin 1
• Consider venous thromboembolism prophylaxis given recent acute illness 2

Common Pitfalls to Avoid

Do not assume that lack of oxygen requirement at rest means the patient is safe to fly. 1 The reduced cabin pressure at cruising altitude (equivalent to 2438m/8000ft) causes arterial oxygen tension to fall to 7.0-8.5 kPa, which can cause significant hypoxemia in patients with underlying lung disease. 1

Do not clear patients to fly based solely on clinical improvement without objective SpO₂ measurement. 1, 2 Patients may feel subjectively better but still have borderline oxygen saturation that becomes problematic at altitude.

Spacers are as effective as nebulizers for treating asthma exacerbations in-flight, so patients should not rely on airline nebulizers being available. 1