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We read with great interest the paper by Mestry et al1 which analysed hypoxic challenge flight assessments in patients with restrictive disorders. In their study they dispute the current British Thoracic Society recommendations, demonstrating that, in this subgroup, all patients planning air travel should have a pre-flight evaluation because, even in patients with normal baseline oxygen saturation (Sao2), arterial oxygen tension (Pao2) can fall below 6.6 kPa during hypoxic challenge.
We wanted to establish whether patients with restrictive disorders (with no lung disease) should be ventilated rather than oxygenated when they are hypoxaemic during flights. In fact, as has been shown by Masa et al,2 only nasal ventilation and not oxygen can normalise baseline nocturnal alveolar hypoventilation in patients with chest wall diseases.
Our group has previously evaluated oxygenation during real flights in healthy subjects,3 demonstrating a mean (SD) oxygen desaturation of 12.8 (6.3)% in long-distance flights (≥2 h) and 4.2 (2.6)% in short-distance flights (<2 h).
We have recently studied two patients with neuromuscular disease during a flight from Porto to Barcelona (duration approximately 1 h 50 min). The first patient was an ambulatory 36-year-old woman with mitochondrial myopathy with a vital capacity (VC) of 400 ml (14%) and the ability to perform air stacking to a maximal insufflation capacity (MIC)4 of 1070 ml (52%). The second patient was a 50-year-old quadriplegic post-polio man with a VC of 560 ml (18%) and an MIC of 1110 ml (35%). Both patients were on continuous non-invasive ventilation (NIV) with a volume-cycled ventilator (mean tidal volume 1200 ml) through a 15 mm mouthpiece during the day and a nasal mask during sleep.
The average Sao2 for the first patient was 97.9%, time with Sao2 <90% was 1.8 min and the minimum Sao2 was 81% (figure 1). For the second patient, the average Sao2 was 97%, time with Sao2 <90% was 1.6 min and the minimum Sao2 was 84% (ventilator disconnection during micturition). The first patient needed to use a manual resuscitator connected to her mouthpiece to maintain adequate ventilation while the battery of her ventilator battery was being changed. Neither patient experienced respiratory distress during the entire flight and both returned home uneventfully.
In conclusion, when patients with restrictive disorders are correctly ventilated (even with a manual resuscitator) they may fly safely, with oxygen saturation profiles identical to healthy subjects, and may not need supplemental oxygen.
Competing interests None.
Provenance and peer review Not commissioned; not externally peer reviewed.
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