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

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)