Introduction: Commercial long distance flights expose travelers to
hypoxia. This hypoxia is even more challenging in patients with preexisting
lung disease. This question is of particular importance for
ex-premature babies with bronchopulmonary dysplasia (BPD) and
children with cystic fibrosis. Aircraft cabins are pressurized to an
altitude of 1500-2400 m above sea level, making the oxygen partial
pressure being 15 kPa, or equivalent to a FiO2 of 15-16% at sea level.
Standardized tests for fitness to flight are either unreliable (normobaric
hypoxia) or technically challenging (hypobaric hypoxia).
Patient, method and result: 5-month-old girl, ex-premature (30
weeks gestational age) with mild bronchopulmonary dysplasia without
need for supplemental oxygen at hospital discharge. Because of the
need for a trans-atlantic flight, we decided to test her tolerance to
hypobaric hypoxia. We did this by monitoring her transcutaneous
oxygen saturation during a car trip of 120 minutes duration from Sion
(512 m), the goal being to reach the Grande Dixence dam (2365 m).
A mobile oxygen source was provided for security reason. The Grande
Dixence dam could not be reached, because of progressivly lowering
of saturation levels (<92%) between 1800 and 2000 m. A moderate
(87%) but persistent (>5 min) desaturation appeared when reaching
2000 m, prompting for oxygen administration and return to the Rhône
valley level. Because of this result, we decided to monitor her oxygen
saturation during the flight, and provide supplemental oxygen if
needed. Our patient received oxygen from arrival at cruising altitude
for the whole flight, which she completed without problem.
Conclusion: In countries with high mountains reachable by car, like
Switzerland, a trip to sufficient altitude while monitoring the
transcutaneous oxygen saturation allows to perform a non expensive
hypobaric hypoxic fitness to flight test. A "false" positive test due to the
position in the car safety seat (as described for preterm and term
newborns), however has to be excluded by a journey in the same
condition and of same duration without change of altitude. A larger
study is needed to define more accurately the protocol and to measure
positive and negative predictive values.