Functional Abnormalities of Pulmonary Fibrosis

Our plain-English summary of Functional Abnormalities of Pulmonary Fibrosis, by George W. Wright (1954).

The study

• Author: George W. Wright
• Published: Read in the Symposium on Occupational Diseases of the Lungs, Massachusetts Medical Society with the Institute of Industrial Medicine, New York University Post-Graduate Medical School, Boston, Oct. 28, 1953; p. 196 (1954)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This article is the text of a lecture the author gave at a 1953 Boston symposium on occupational lung diseases. It compared lung function in silicosis and asbestosis. For silicosis it drew mainly on studies by many investigators. For asbestosis it described, without tables or numbers, findings from 57 men with varying exposure to airborne asbestos fiber, studied at the Edward L. Trudeau Foundation. The fiber type was not named. In typical asbestosis the ability to move air was usually little or not impaired, but total lung volume was likely to be slightly to moderately reduced. Arterial oxygen pressure was usually below normal, carbon dioxide pressures tended to stay normal, and men with asbestosis tended to overbreathe during exercise. Some men with low blood oxygen still had average capacity for work. X-ray and function findings did not always match. Exposure intensity and duration showed only a gross correlation with abnormalities, and some heavily exposed men developed none. The author concluded that the chief abnormality in asbestosis was impaired oxygen transfer to the blood, unlike the loss of breathing power in conglomerate silicosis.

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: Symposium lecture (narrative overview) describing lung-function findings in silicosis from the literature and in asbestosis from a group studied at the author's institution; no tables or numerical results for the asbestos group
• Who was studied: 57 men with varying degrees of exposure to airborne asbestos fiber, studied at the Department of Physiology of the Edward L. Trudeau Foundation in the years before 1953; a preliminary report was given in September 1952
• Exposure: Airborne asbestos fiber of varying degree, intensity and duration; fiber type and jobs not specified. Silicosis (crystalline silica) was discussed for comparison.
• Main results:
  • In typical asbestosis there was little, and often no, impairment of the ability to ventilate the lungs (maximum breathing capacity)
  • In typical asbestosis a slight to moderate reduction in total lung volume was described as likely
  • Arterial oxygen pressure was usually below normal in asbestosis
  • Carbon dioxide pressures in asbestosis were described as apt to be within normal limits, in both lung gas and lung blood
  • During exercise, a person with asbestosis was described as apt to overbreathe; the oxygen ventilation equivalent was found to be elevated
  • Some men with below-normal arterial oxygen content still had average capacity for work
  • Three situations were seen in asbestosis: abnormal function without a definite X-ray abnormality, both abnormal, and an X-ray abnormality without abnormal function
  • There was a gross correlation between the intensity and duration of asbestos exposure and the development of X-ray or function abnormalities
  • Some men with prolonged and very intense exposure developed no X-ray or function abnormality
  • Men with silicosis became short of breath mainly from loss of breathing power; men with asbestosis mainly because their breathing load during exercise was unusually great
  • Cor pulmonale (heart strain from lung disease) was described as a not unusual complication of both conglomerate silicosis and asbestosis
• The authors' conclusion: The author concluded that the chief abnormality in asbestosis is impaired oxygen transfer to the blood rather than impaired breathing ability. The author also concluded that the function abnormalities of silicosis and asbestosis are distinctly different in the earlier stages of the two diseases.
• Limitations the authors state:
  • Men were compared with the average normal man, not with their own measurements before injury, so the data cannot show an absence of impaired work capacity
  • The material gave no evidence on the shortest duration or intensity of exposure needed to produce recognizable asbestosis

Topics

Medical terms in this study, explained in our Lexicon: Pulmonary Fibrosis, Occupational Lung Disease, Silicosis.

Browse return to medical research.