Long term changes in lung function after surgical treatment of bullous emphysema in smokers and ex-smokers

Eleven patients who had received surgical treatment for bullous emphysema had regular assessment of lung function for a minimum of four years (mean 8.8, range 4-20 years). For each patient we estimated the annual rate of change in FEV1 and "relaxed" vital capacity (before and after bronchodilator aerosol) and in carbon monoxide transfer factor (TLCO), transfer coefficient (KCO), and arterial carbon dioxide and oxygen tensions (Paco2 and Pao2). Among the 11 who had undergone operation, all lung function variables declined at a faster rate in those who continued to smoke than in ex-smokers, the difference in rate being significant (p less than 0.05) for FEV1 (before bronchodilator), TLCO and KCO. In ex-smokers the rate of change in most lung function indices was not significantly different from zero--that is, no change; in smokers all lung function indices except Paco2 declined at a rate significantly greater than zero. These findings suggest that long term results of surgical treatment for bullous emphysema are likely to be greatly improved if patients abandon smoking.