Cigarette smoke inhalation and the acute airway response

The acute airway response to smoking varying numbers (one to four) of identical cigarettes in rapid succession and smoking single cigarettes of differing tar/nicotine yields was assessed repeatedly in 13 healthy smokers. The airway response was variable, indicating airway narrowing consistently in only three subjects. There appeared no difference between forced spirometry and measurement of airway resistance in detecting the airway response. No relationship was observed between the airway response and amount of smoke inhaled into the lungs as measured either by changes in venous blood nicotine or percentage carboxyhaemoglobin. When five smokers inhaled smoke directly from a cigarette acute airway narrowing was consistently observed. A normal smoking pattern consisting of an initial drag of smoke into the mouth, followed after a pause by inhalation of smoke diluted with air, did not consistently cause airway narrowing although similar amounts of smoke as the direct drag were inhaled as assessed by changes in venous blood nicotine. The manner of smoke inhalation affects the relative concentrations of the different constituents of smoke reaching the lungs and also appears to be the main determinant of the acute airway response to smoking, which was unrelated to the number of cigarettes smoked or the tar content of the smoke. This suggests that patterns of smoke inhalation may influence the pathogenesis of bronchial disease associated with smoking.