Acute effects of smoking a single cigarette on the airway resistance and the maximal and partial forced expiratory flow volume curves.

The acute airway response to smoking a single cigarette was assessed in eight symptom-free male smokers. The changes in airway function were determined using a computer analysis of maximal and partial expiratory flow volume curves together with measurement of airway resistance. The amount of smoke inhaled was assessed by measuring levels of nicotine in venous blood. When the results of all studies were analysed for the group as a whole only small and inconsistent changes in airway function were observed after smoking a cigarette, although all the subjects appeared to inhale the smoke. Although the group showed inconsistent changes, one subject exhibited a change on all four occasions in the studies using the maximal and partial expiratory flow volume curves. This was seen particularly for Vmax50 and Vmax40 obtained from the maximal and partial expiratory flow volume curves respectively. There appeared to be no difference between the two manoeuvres in their sensitivity to smoke-induced change. One subject showed a response to smoking when airways resistance was measured but this was on only one of two occasions. It is therefore possible that certain smokers are more susceptible to inhaled cigarette smoke and such individuals may be those who develop chronic airflow obstruction. The absence of a group effect was attributed to any smoking response being smaller than the other factors which affect measurements of airway function.