Bronchoalveolar lavage and 99mTc-DTPA clearance as prognostic factors in asbestos workers with and without asbestosis

Our plain-English summary of Bronchoalveolar lavage and 99mTc-DTPA clearance as prognostic factors in asbestos workers with and without asbestosis, by N. al Jarad, A.R. Gellert, R.M. Rudd (Respiratory Medicine, 1993).

The study

• Authors: N. al Jarad, A.R. Gellert, R.M. Rudd
• Journal: Respiratory Medicine
• Published: 1993;87(5):365-74
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The aims of this study are to investigate the change-over time of lung function and chest radiographic findings in patients with asbestosis (AS) and asbestos workers without asbestosis (AW). Secondly, to correlate these changes with broncho-alveolar lavage (BAL) profiles and with lung epithelial permeability, as detected by half-time lung-to-blood (t1/2 LB) clearance of an inhaled aerosol of diethylene triamine pentacetate labelled with technetium 99 (99mTc-DTPA) obtained a mean period of 4.2 yr (range 2.3-5.8) previously. Thirty-three patients with asbestosis and 24 asbestos workers with substantial asbestos exposure were followed-up. Nineteen healthy smokers (HS) with no asbestos exposure who were followed up for a mean period of 3.9 yr were taken as a control group for spirometric changes. Compared with AW, FEV1, FVC and TLCO were lower in AS (P < 0.0001 in each case). Smoker AS and AW had lower numbers (P < 0.03) and percentages (P < 0.004) of BAL lymphocytes and higher numbers (P < 0.04) and percentages (P < 0.02) of BAL neutrophils plus eosinophils than ex- and non-smokers. Annual declines of FEV1 (dFEV1 yr-1) and FVC (dFVC yr-1) in AS and AW were significantly greater than in HS and predicted annual declines (P < 0.002 in each case). Annual declines of TLCO (dTLCO yr-1) and KCO (dKCO yr-1) in AS and AW were significantly greater than predicted annual declines (P < 0.002 in each case). No significant differences were noted between AS and AW in annual declines in any lung function measurement. dTLCO yr-1, dKCO yr-1 were significantly greater in smokers than in ex- and non-smokers, (P < 0.05 and P < 0.04 respectively). Annual decline did not relate to base line values for any lung function measurement. Numbers and proportions of BAL lymphocyte were higher (P < 0.008 and P < 0.02, respectively) and numbers and proportions of BAL neutrophils and eosinophils were lower (P < 0.02 and P < 0.03, respectively) in patients in whom dTLCO yr-1 was less than 0.3 mmol min-1 kPa-1 than in patients in whom dTLCO yr-1 was more than 0.3 mmol min-1 kPa-1. dTLCO yr-1 inversely correlated with t1/2 LB; r = 0.51; (P < 0.008). Patients in whom the radiograph remained unchanged had higher numbers (P < 0.002) and percentages (P < 0.001) of BAL lymphocytes than patients in whom the radiograph deteriorated.(ABSTRACT TRUNCATED AT 250 WORDS)

In plain English

This follow-up study from the London Chest Hospital re-examined asbestos workers who had earlier had bronchoalveolar lavage (BAL, a washing of the lung airways) and a test of how fast an inhaled radioactive tracer (99mTc-DTPA) passes from lung to blood. Of 73 people first assessed, 48 had worked in lagging. 33 with asbestosis and 24 asbestos workers without asbestosis were followed up, after a mean of 4.2 years. 19 healthy smokers without asbestos exposure served as a comparison group for changes in spirometry (FEV1 and FVC). Yearly declines in FEV1 and FVC in both asbestos groups were significantly greater than in the healthy smokers and than predicted; declines in gas transfer (TLCO and KCO) were significantly greater than predicted. Declines did not differ significantly between workers with and without asbestosis. Chest X-rays worsened in 19 of 50 subjects. Fewer lymphocytes and more neutrophils plus eosinophils in the earlier lavage, and faster tracer clearance, were associated with greater decline in gas transfer. The authors noted that the clearance link could be mainly due to smoking and that follow-up was relatively short.

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: Follow-up (longitudinal) study re-examining patients who had earlier had bronchoalveolar lavage and DTPA clearance measurements, to judge whether these tests predicted later change
• Who was studied: 73 people were first assessed at the London Chest Hospital (37 with asbestosis, 36 asbestos workers without asbestosis). 57 were followed up (33 with asbestosis, 24 without). Six died during the interval and one was excluded after pneumonectomy for lung cancer. The groups analysed were 30 with asbestosis (12 current smokers, 16 ex-smokers, 2 non-smokers) and 20 without asbestosis (12 ex-smokers, 8 non-smokers). 19 healthy smokers with no asbestos exposure, followed for a mean of 3.9 years (range 2 to 5 years), were the control group for spirometric changes.
• Exposure: Occupational asbestos exposure. 48 of the 73 originally assessed had worked in the lagging industry; the rest had done asbestos cutting, milling and spinning. Fiber types were not specified. Asbestos bodies in lavage fluid were counted.
• Main results:
  • Yearly declines in FEV1 and FVC in both the asbestosis group and the asbestos workers without asbestosis were significantly greater than in the healthy smokers and than predicted declines (P less than 0.002 in each case).
  • Yearly declines in gas transfer (TLCO and KCO) in both asbestos groups were significantly greater than predicted declines (P less than 0.002 in each case). These were not compared with the healthy smokers.
  • Declines in lung function did not differ significantly between those with asbestosis and asbestos workers without asbestosis.
  • Among asbestos-exposed subjects, current smokers had greater yearly declines in TLCO and KCO than ex- and non-smokers (P less than 0.05 and P less than 0.04). Declines in FEV1 and FVC did not differ significantly by smoking.
  • Yearly declines in lung function were not related to asbestos body counts, duration of asbestos exposure or time since first exposure.
  • The chest X-ray worsened in 19 subjects (6 without asbestosis, 13 with asbestosis; 39%) and stayed unchanged in 31 (14 without, 17 with; 61%).
  • Subjects whose yearly TLCO decline exceeded 0.3 mmol per minute per kPa (twice the group mean) had significantly lower BAL lymphocyte numbers and percentages (P less than 0.008 and P less than 0.02). They also had significantly higher neutrophils plus eosinophils (P less than 0.02 and P less than 0.03) than those with smaller declines. FEV1, FVC and TLC showed no correlations with BAL counts.
  • Subjects whose chest X-ray stayed unchanged had higher BAL lymphocyte numbers (P less than 0.002) and percentages (P less than 0.001) than those whose X-ray worsened.
  • In the two asbestos groups combined, faster DTPA clearance (shorter half-time) was associated with greater TLCO decline (r = -0.51, P less than 0.008). Analysed separately, the correlations were r = -0.58 in smokers and r = -0.40 in ex- and non-smokers, and neither was significant.
  • Subjects whose chest X-ray worsened tended to have faster DTPA clearance, but this was not statistically significant (P = 0.06).
• The authors' conclusion: The authors concluded that lung function declines faster in people with asbestosis and in asbestos workers without asbestosis than in controls. They also concluded that increased BAL neutrophils and faster DTPA clearance are associated with worse functional and radiological outcome than increased BAL lymphocytes and slower DTPA clearance.
• Limitations the authors state:
  • The link between faster DTPA clearance and greater gas-transfer decline could be mainly due to smoking.
  • The mean follow-up of 4.2 years is relatively short for a slowly progressive condition like asbestosis.
  • Gas transfer measurements were not obtained in all subjects because of logistic problems.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Bronchoalveolar Lavage (BAL), Asbestos Exposure, FEV1.

Related studies

• Gallium lung scanning and bronchoalveolar lavage in crocidolite-exposed workers — A.A. Hayes, B. Mullan, et al. (1989)
• Influence of cigarette smoking on bronchoalveolar lavage cellularity in asbestos-induced lung disease — D.A. Schwartz, J.R. Galvin, et al. (1992)
• Bronchoalveolar lavage cell and lymphocyte phenotype profiles in healthy asbestos-exposed shipyard workers — J.M. Wallace, J.S. Oishi, et al. (1989)
• Bronchoalveolar lavage analysis, gallium-67 lung scanning and soluble interleukin-2 receptor levels in asbestos exposure — G.L. Delclos, D.G. Flitcraft, et al. (1989)
• Distribution of asbestos bodies in the human lung as determined by bronchoalveolar lavage — H. Teschler, N. Konietzko, et al. (1993)
• Asbestosis occurring after brief inhalational exposure: usefulness of bronchoalveolar lavage in diagnosis — R.G. Barbers, J.L. Abraham (1989)

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