Pulmonary Disorders: COPD

Oxygen Treatment in COPD

Oxygen supplementation in COPD may be continuous or only at night. In either case, it implies a high level of loss of functional lung tissue. LEOs with COPD who might be on continuous supplemental oxygen would, likely, have reduced exercise capacity such that they would be unable to safely and effectively perform essential job functions based on criteria for instituting such treatment (see Table 7).

Table 7: Criteria for Starting Long-term Oxygen Therapy in COPD22

Continuous Oxygen Use
Resting PaO2 ≤55 mm Hg
Resting PaO2 of 56-59 mm Hg plus any of the following

• Dependent edema
• P pulmonale on the electrocardiogram (P wave exceeding 3 mm in standard lead II, III, or aVF)
• Polycythemia (hematocrit, >56%)

Intermittent Oxygen Use
Desaturation (SpO2 ≤88%) with activity
Desaturation (SpO2 ≤88%) at night

Chronic hypoxemia in severe COPD may contribute to the cognitive decline noted in this population versus age-matched populations with COPD. Long-term oxygen therapy (LTOT) has been found to be associated with less rapid decline in cognitive function.23,24 In these evaluations 88% oxygen saturation was used as the criterion for hypoxemia.

A panel of medical experts convened to advise the Federal Motor Carrier Safety Administration in the United States has recommended that commercial truck driver candidates with COPD and a screening pulse oximetry of less than 92% have arterial blood gas analysis. The panel further recommended that if arterial oxygen partial pressure is less than 65 mmHg (at less than 5,000 ft altitude), the candidate be disqualified.25

Oxygen supplementation may be either via oxygen containing gas cylinders or via use of an oxygen concentrator. The latter provides gas with oxygen representing around 90% of the content. This is done via extracting the nitrogen. Thus, other gases remain in the mix such as CO2, argon, and water vapor.