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 ( t 1 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, FEV 1, FVC and T lCO 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 FEV 1 (dFEV 1 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 T lCO (d T lCO yr −1) and KCO (d KCO 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. d T lCO yr −1, d KCO 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 d T lCO yr −1 was less than 0·3 mmol min −1 kPa −1 than in patients in whom d T lCO yr −1 was more than 0·3 mmol min −1 kPa −1. d T lCO yr −1 inversely correlated with t 1 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. It is concluded that decline in lung function is greater in AS and AW than in controls. Increased BAL neutrophils and faster DTPA clearance are associated with worse functional and radiological outcome than increased BAL lymphocytes and slower DTPA clearance.