Single breath diffusing capacity in the industrial setting

Our plain-English summary of Single breath diffusing capacity in the industrial setting, by B. Make, A. Miller, G. Epler, et al (Chest, 1982).

The study

• Authors: B. Make, A. Miller, G. Epler, J.B. Gee
• Journal: Chest
• Published: 1982;82(3):351-6
• Type of article: Review
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001774).

In plain English

This article was a review based on a 1980 panel discussion at the American College of Chest Physicians meeting. Its subject was a lung test, the single breath diffusing capacity for carbon monoxide, which the article describes as an index of gas exchange in the lungs. The article reported no new study of its own. It covered how to perform and calibrate the test, which normal-value equations to use, and the test's role for workers exposed to hazardous dusts. The authors noted that smokers have diffusing capacity about 80 percent of that of normal nonsmokers, so results in smokers should not be over-interpreted as occupational disease. They recommended two recent sets of normal-value equations, from Crapo and from Miller, using nonsmoker equations and documenting smoking history. Most of the industrial studies they cited came from asbestos-exposed populations. In one of those earlier studies, 12 percent of employees with an isolated low result developed asbestosis within four to six years. The authors concluded that the test is a valuable screening test and a sensitive indicator of occupational interstitial lung disease, but needs careful technique.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review of published literature, arising from a panel discussion
• Who was studied: No study population of its own. The authors reviewed published studies of normal values and industrial studies, mostly of asbestos-exposed populations.
• Exposure: Fibrogenic mineral dusts such as asbestos, discussed in general terms. No fiber types are specified.
• Main results:
  • The authors stated that smokers have diffusing capacity approximately 80 percent of that of normal nonsmokers, and cautioned against attributing low results in smokers to occupational disease.
  • The authors recommended the two more recent prediction equations, those of Crapo and of Miller.
  • The authors stated that defining the lower limit of normal as a fixed percentage of the predicted value (75 or 80 percent) has no statistical validity.
  • In a cited earlier study of 44 patients with interstitial lung disease and a normal chest X-ray, diffusing capacity was abnormal in 73 percent and vital capacity was reduced in 57 percent.
  • In a cited earlier study of 46 patients with biopsy-proven asbestosis, diffusing capacity correlated best with graded tissue abnormalities.
  • In a cited earlier study of employees in an industrial setting, 12 percent of those with an isolated abnormal diffusing capacity developed asbestosis within four to six years.
  • In a cited earlier study, 15 percent of 345 patients with pneumoconiosis had severe impairment, compared with less than 1 percent of 938 working asbestos-exposed employees.
  • In the authors' opinion, a yearly variation of 10 percent is probably within the expected range, while a loss of 20 percent or more most likely indicates lung disease.
• The authors' conclusion: The authors concluded that the test is a valuable screening test and a sensitive indicator of occupational-related interstitial lung disease, but that careful attention to technical details is needed.
• Limitations the authors state:
  • The authors stated that no epidemiologic studies had been published on what yearly decrease in diffusing capacity is clinically significant.
  • The authors stated that there is no uniform approach to measuring diffusing capacity in smokers.

Topics

Medical terms in this study, explained in our Lexicon: Diffusing Capacity (DLCO).

Related studies

• Pulmonary elastic recoil and diffusing capacity in subjects with intermediate concentrations of alpha-1 antitrypsin — A.W. Musk, P.W. Robertson (1976)
• Biphasic lung diffusing capacity: detection of early asbestos induced changes in lung function — Z. Dujić, J. Tocilj, et al. (1992)
• Diffusing capacity and forced vital capacity in 5,003 asbestos-exposed workers: relationships to interstitial fibrosis (ILO profusion score) and pleural thickening — A. Miller, R. Warshaw, et al. (2013)
• Association between neutrophil concentration in bronchoalveolar lavage fluid and recent losses in diffusing capacity in men formerly exposed to asbestos — M.R. Cullen, W.W. Merrill (1992)
• Relationship of mortality, occupation, and pulmonary diffusing capacity to pleural thickening in the First National Health and Nutrition Examination Survey — D.P. Loomis, G.W. Collman, et al. (1989)
• Reduced diffusing capacity as an isolated finding in asbestos- and silica-exposed workers — J.G. Garcia, D.E. Griffith, et al. (1990)

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