Gax-exchange abnormalities are inevitable consequences of progressive COPD. Hypercapnia has a predictable correlation with FEV1 and usually occurs when FEV1 declines below 1 Liter. Hypoxemia, on the other hand, may not be as predictable. To assess the relationship between FEV1 and hypoxemia in COPD, we reviewed medical records of a group of hypoxemic patients with COPD receiving home oxygen therapy.
We retrospectively reviewed medical records of 19 patients with COPD (8 females, 11 males, age rage: 49-76 years; mean age: 64.9 years) on home oxygen therapy qualifying under Medicare criteria. Patients were subdivided into two groups, one with FEV1<1.0L and the other with FEV1>1.0L.
Nine (47%) patients were found to have FEV1>1.0L, 3 of whom (16%) had FEV1>1.5L. Ten (53%) patients had FEV1<1.0L, 1 of whom (5%) had FEV1<0.5L. Statistical analysis using Z-test showed no significant difference between the two groups (P=0.816).
Unlike hypercapnia which is usually associated with FEV1<1.0L in COPD, hypoxemia develops unpredictably and is not necessarily associated with a specific level of FEV1, occuring even in non-severe obstruction.
Evaluation of COPD patients for the presence of complicating hypoxemia necessitating oxygen therapy should begin at an earlier stage of COPD.
FEV1<1.0L>1.0L<0.50.5-1.01.0-1.5>1.5Number of PatientsMales0461Females1502Total10 (52.6%)9 (47.4%)
S. Momany, None.