Rapid improvement in abnormal pulmonary epithelial permeability after stopping cigarettes

Abstract
A new, non-invasive method of measuring pulmonary epithelial damage in man was compared with traditional tests of small-airway function. Pulmonary epithelial permeability was expressed as the half-time clearance from the lung into blood of 99mTc-diethylene triaminepenta-acetic acid (99mTc-DTPA) deposited predominantly in the alveoli from an inhaled aerosol. Recovery from abnormal pulmonary permeability was recorded after stopping smoking for 21 days in a group of young symptomless cigarette smokers. Before stopping smoking there was a significant correlation between half-time lung clearance of 99mTc-DTPA and carboxyhaemoglobin concentration (r=0·69; p 99mTc-DTPA had increased significantly (p <0·001) from a baseline of 15·8 min (SEM 1·3 min) to 25·5 min (SEM 2·5 min). The mean half-time clearance continued to increase to a maximum of 35·5 min (SEM 3·1 min) at seven days, but was significantly less than the reported half-time clearance for non-smokers (59 min, SEM