COMPARATIVE STUDY
JOURNAL ARTICLE

Membrane and capillary blood components of diffusion capacity of the lung for carbon monoxide in pulmonary sarcoidosis: relation to exercise gas exchange

Christine Lamberto, Hilario Nunes, Philippe Le Toumelin, Florence Duperron, Dominique Valeyre, Christine Clerici
Chest 2004, 125 (6): 2061-8
15189922

BACKGROUND: Resting pulmonary diffusing capacity of the lung for carbon monoxide (DLCO) is known to be the best predictor of arterial desaturation during exercise in patients with sarcoidosis. However, the relative contribution of each of the two components of DLCO-alveolar membrane diffusing capacity (Dm) and pulmonary capillary blood volume (Vc)-remains unclear.

STUDY OBJECTIVES: To evaluate which component is responsible for the decrease of resting DLCO in patients with sarcoidosis, and to determine which resting pulmonary function test, including Dm and Vc, is the best predictor of gas exchange abnormalities during submaximal exercise.

DESIGN: Prospective analysis of patients referred to our department of respiratory medicine.

PATIENTS: Twenty four patients with pulmonary sarcoidosis were separated into two groups according to chest radiographic findings: group 1, stages 2 and 3 (n = 15); group 2, stage 4 (n = 9). All the patients completed pulmonary function tests (flows, volumes, single-breath DLCO, transfer coefficient [Ka], Dm, Vc) and submaximal exercise (two steady-state levels of mild and moderate exercise corresponding respectively to a target oxygen consumption of approximately 10 to 15 mL/min/kg).

RESULTS: DLCO was reduced in the two groups (group 1, 63 +/- 16% of predicted; group 2, 64 +/- 16% of predicted). Dm was severely decreased (group 1, 58 +/- 24% of predicted; group 2, 51 +/- 15% of predicted), whereas Vc was unchanged or only mildly decreased (group 1, 81 +/- 18% of predicted; group 2, 85 +/- 28% of predicted). Whatever the group of patients and the exercise level, Dm and DLCO were the strongest predictors (p < 0.001) of gas exchange abnormalities. Ka or volumes were weak predictors, and Vc or flows were not related with exercise gas exchange.

CONCLUSIONS: This study demonstrates that a decrease in Dm mostly accounts for resting DLCO reduction, and that Dm as well as DLCO are highly predictive of gas exchange abnormalities at exercise in patients with sarcoidosis.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
15189922
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"