While the article reference obesity, the end of the article provides some general guidelines for air travel which seem to be worth noting.
"If the patient has resting saturations of less than 92% they require supplemental
oxygen in-flight. If a patient's 6-minute walk test results drop to an O2 Sat (oxygen
saturation) in the low 80% range, that person will require supplemental oxygen."
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Endocrinology
Obesity & COPD: Risky Combo for Air Travel?
Simulated flight study at ERS reported lowered blood oxygen levels in participants
In a flight simulation situation, individuals with obesity and chronic obstructive pulmonary disease (COPD) experienced relevant hypoxia, according to German researchers.
Christina Priegnitz, MD, of the Wissenschaftliches Institut am Krankenhaus Bethanien in Solingen, Germany, and colleagues, reported eight out of 11 obese COPD patients experienced reduced blood oxygen saturation at high altitudes in a hypoxia altitude simulation test. Also, nine out of 11 experienced reduced blood oxygen saturation using the hyperbaric chamber test, suggesting these individuals are potential candidates for pre-flight testing.
In comparison, eight obese individuals without COPD underwent the same hypoxia altitude simulation test, and there were no instances of reduced oxygen saturation. Three of eight control participants who underwent the hyperbaric chamber test experienced reduced (less than 90%) oxygen saturation, the authors reported in a poster at the European Respiratory Society International Congress.
"Most obese COPD patients experienced relevant hypoxia in simulated flight, supporting the demand for pre-flight testing to assess ability to fly and recommend oxygen supplementation where necessary," the authors stated.
"Travelers in an aircraft are exposed to decreased atmospheric and oxygen partial pressure, leading to reduced blood oxygen saturation. COPD patients, depending on disease severity, are highly susceptible for resulting hypoxia due to gas exchange impairments," Priegnitz explained. "Since concomitant obesity may be associated with ventilation-perfusion mismatch, this could lead to further aggravation of hypoxia."
Priegnitz's group, which included scientists from an aerospace program, enrolled 19 individuals. The healthy obese patients were about 42-years-old and had an average body mass index (BMI) of 36 kg/m2. The obese COPD patients were about 60-years-old and had an average BMI of 33 kg/m2.
The hypoxia altitude simulation (HAST) test was performed by applying 15.1% oxygen via a face mask at rest in the sitting position under normobaric conditions. The second test was done in a hyperbaric chamber (HCT) set to achieve a pressure of 760 millibars, corresponding to approximate in-flight cabin pressure.
The lowest stable oxygen saturation was measured for both tests as well as on room air. Oxygen saturation levels were normal in room air, but significantly reduced at simulated higher altitudes, Priegnitz said. The reduced blood oxygen saturation levels for the COPD patients versus the healthy patients were:
At rest: 95 versus 98
HAST: 88 versus 93
HCT: 89 versus 92
Priegnitz's group cautioned that the control group "had a maximal BMI <40kg/m² and were younger, impairing generalization of results and affecting comparability with the COPD group." On lung function tests, the obese participants without COPD scored better than the obese COPD patients.
Nonetheless, Priegnitz said that "if I had a patient with COPD and who was obese, I would send him or her to a clinic where these tests could be performed." She added the testing takes about half an hour, including time to set up the devices.
The COPD Foundation recommends using the following algorithm to determine if a COPD patient will need in-flight oxygen: "If the patient has resting saturations of less than 92% they require supplemental oxygen in-flight. If a patient's 6-minute walk test results drop to an O2 Sat (oxygen saturation) in the low 80% range, that person will require supplemental oxygen."
"These are reasonable suggestions for people with COPD who are going to get on an airplane," said Michael Furian, a PhD candidate, at the University Hospital of Zurich, who is specializing in high altitude effects on pulmonary disease.
Performing tests on patients to determine how well they adapt to high altitude situations should be worthwhile; those who are found to have decreased oxygen saturation may want to take an oxygen source on the plane with them.
But Furian, who was not involved in the study, told MedPage Today that "the question is still not solved as to whether they are protected because they have always had hypoxia or whether they are actually suffering from brain damage due to lack of oxygen."
www.medpagetoday.com/endocrinology/obesity/60075
