Diffusing capacity of the lung for carbon monoxide.
DLCO
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DLCO stands for the diffusing capacity of the lung for carbon monoxide,[1] the test used to determine this parameter. DLCO is the extent to which oxygen passes from the air sacs of the lungs into the blood. It was introduced in 1909.[2]
Contents |
Mechanism of test
The DLCO Test
This test involves measuring the partial pressure difference between inspired and expired carbon monoxide. It relies on the strong affinity and large absorption capacity of erythrocytes for carbon monoxide and thus demonstrates gas uptake by the capillaries that is less dependent on cardiac output. [3]
Factors affecting DLCO
Reduction
DLCO is decreased in any condition which affects the effective alveolar surface area:
- Hindrance in the alveolar wall. e.g. fibrosis, alveolitis, vasculitis
- Decrease of total lung area, e.g. emphysema.
- Uneven spread of air in lungs, e.g. emphysema.
- Pulmonary embolism
- Cardiac insufficiency
- Pulmonary hypertension
- Bleomycin (upon administration of more than 200 units)
- Anemia-due to decrease in blood volume
Increase
Factors increasing dlco include polycythaemia and increased pulmonary blood volume as occurs in exercise,congestive heart failure. Other factors are left-to-right pulmonary shunting that occurs in left heart failure,alveolar hemorrhage and smoking within 24 hours of the test [4].
Factors affected by DLCO
Reduction
A DLCO of less than 40% predicted portends a poor prognosis for lung cancer resection. FEV1 is of lesser prognostic value for lung resection survival.[4]
References
- ^ Macintyre N, Crapo RO, Viegi G, et al. (October 2005). "Standardisation of the single-breath determination of carbon monoxide uptake in the lung". Eur. Respir. J. 26 (4): 720–35. doi:. PMID 16204605. http://erj.ersjournals.com/cgi/pmidlookup?view=long&pmid=16204605.
- ^ Hughes J, Bates D (2003). "Historical review: the carbon monoxide diffusing capacity (DLCO) and its membrane (DM) and red cell (Theta.Vc) components". Respir Physiol Neurobiol 138 (2-3): 115–42. doi:. PMID 14609505.
- ^ Sue DY, Oren A, Hansen JE & Wasserman K (1987). Diffusing capacity for carbon monoxide as a predictor of gas exchange during exercise. N. Engl. J. Med., 316(21):1301-1306.
- ^ Diffusion lung capacity for carbon monoxide (DLCO) is an independent prognostic factor for long-term survival after curative lung resection for cancer (p n/a) Michael J. Liptay, Sanjib Basu, Michael C. Hoaglin, Neil Freedman, L. Penfield Faber, William H. Warren, Zane T. Hammoud, Anthony W. Kim Published Online: Oct 1 2009 8:20AM DOI: 10.1002/jso.21407
[4] Ruppel, G. L. (2009). Manual of Pulmonary Function Testing. ISBN: 978-0-323-05212-2
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 | Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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