VETERANS HEALTH ADMINISTRATION CLNICAL PRACTICE GUIDELINE FOR THE MANAGEMENT OF COPD OR ASTHMA 
Outpatient Management of COPD: Management of Air Travel (A7)

A. Patients with Stable Chronic Obstructive Pulmonary Disease (COPD) Planning Air Travel - Commercial airliners cruise at altitudes up to 44,000 feet and their cabins are pressurized to altitudes of about 8,000 feet, which is equivalent to an inspired O2 concentration at sea-level of about 15 percent. Hypoxemic COPD patients experience falls in their PaO2 that average 25 mmHg but which may range up to 30 mmHg at 8,000 feet as compared with sea level. Since their sea-level PaO2 values are on the steep part of the oxygen-hemoglobin dissociation curve, the fall in SaO2 with falls in PaO2 may be quite sharp. Oximetry while a client breathes 15 percent O2 for 30 minutes provides an estimate of the PaO2 at altitude and compares well with simulated altitude exposure in a hypobaric chamber. The PaO2 at ground level (PaO2G) and the FEV1 are useful predictors of the PaO2 at altitude (PaO2Alt) according to the following equation (r = 0.847, p < 0.0001):

PaO2 Alt mmHg = 0.453 [PaO2G mmHg + 0.386 FEV1 % pred] + 2.44

Since the FEV1 influences PaO2Alt, it is important to optimize the FEV1 by pharmacotherapy before and during air travel. In patients with COPD, oxygen flows of 2 to 3 L/min are generally sufficient to restore SaO2 to 90-percent hydration should be maintained, and alcoholic beverages should not be taken during flight.


TABLE OF EVIDENCE

Intervention References Grade of Evidence Strength of Recommendation
Effect of breathing 15-percent O2 (hypoxia-altitude-simulation test) and exposure to altitude of 8,000 feet in hypobaric chamber on PaO2 eucapnic, stable COPD clients. Predicting PaO2 at altitude from PaO2 at ground level. Dillard 1989, 1993, 1995 

Gong 1984

 B  2b 
 
Intervention References Grade of Evidence Strength of Recommendation
Altitude physiology; pre-flight evaluation, recommendations re: oxygen therapy during air travel. Gong 1989, 1992 B 2b
Liter flows of oxygen and devices for correcting hypoxemia during flight. Berg 1992 

Vohra 1993

 B 

B

 2b 

2b

B. Room Air PaO2 > 70 mmHg, with Eucapnia SaO2 > 93 Percent - Some authors have chosen a predicted altitude PaO2 of 50 mmHg as the threshold below which supplementary oxygen should be prescribed. However, this value is arbitrary with no outcome studies to support this recommendation. Eucapnic COPD patients are often well acclimated to hypoxemia and in altitude simulation tests, many stable, eucapnic patients with COPD and no known heart disease are relatively asymptomatic at rest. They do not experience cardiac arrhythmias and have good short-term tolerance to PaO2 values of 35 to 40 mmHg (Gong 1992). Thus, the advising physician must still rely largely on clinical evaluation, judgment, and a history of successful flights in advising each patients who wishes to fly.

TABLE OF EVIDENCE

Intervention References Grade of Evidence Strength of Recommendation
Deciding regarding oxygen during flight. Gong 1992 B 2b
 
C. Room Air PaO2 56 to 69 mmHg - The morbidity and mortality due to in-flight hypoxemia in COPD patients are unknown and are largely anecdotal but based on available evidence, are very low. Cardiovascular and neurologic events are more frequent than respiratory events. It seems reasonable to take the position that the effects of hypoxemia in COPD patients at altitude are most likely to be manifest in the cardiovascular or central nervous systems. Hence, greater caution should be exercised in correcting in-flight hypoxemia in COPD patients who have cardiovascular disease or ischemic cerebrovascular disease. COPD patients vary in their ability to hyperventilate and to decrease their PaCO2 in response to worsening hypoxemia, as is the case with normal persons. Hypercapnic persons have the least ability to hyperventilate in response to hypoxemia, and will therefore have more severe hypoxemia at altitude than eucapnic persons. In the presence of cardiovascular disease or hypercapnia, it is prudent to recommend oxygen therapy for all flights.

TABLE OF EVIDENCE

Intervention References Grade of Evidence Strength of Recommendation
Morbidity and mortality during air travel. Cummins 1988, 1989 

Speizer 1989

 B 2b 
 

D. Patient is on Long-Term Oxygen Therapy - It is self-evident that oxygen supplementation is required during flight for all persons who are on long-term oxygen therapy. (See Module A5, Long-Term Oxygen Therapy). Even very severely ill patients such as lung transplant recipients can fly, although an air ambulance may be necessary to assure complete safety.


TABLE OF EVIDENCE

Intervention References Grade of Evidence Strength of Recommendation
Safety of air travel for cardiopulmonary patients with severe lung disease. Kramer 1995 B 2b
 

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