Oxygen therapy-induced hypercapnia: fact or fiction?

Abstract

Oxygen therapy is assumed to increase hypercapnia in chronic obstructive pulmonary disease (COPD). If the mechanisms have been investigated since over 60 years, none of them is formally involved. The predominant mechanism appears to be a change in the ventilation/perfusion ratio, but the degree of its involvement varies, probably depending on the severity of the underlying disease. Clinical studies are more recent, however with contradictory results. It seems that only a small part of COPD patients experienced CO₂ retention during oxygen therapy; side-effects are unclear. Nevertheless, titrated administration of oxygen to patients with COPD appears a safe procedure without deleterious effects, provided that a sufficient PaO₂ can be obtained.