Airways response to inhaled XXXX smoke: time course, dose dependence and effect of volume history.

@entity286 @entity1239
We have measured puff by puff the effect of smoking three brands of cigarettes with different composition on airways resistance (Raw) thoracic gas volume (TGV) and the maximal expiratory flow volume (MEFV) curve. Raw increased significantly with all three brands of cigarettes after one puff. The maximum effect was reached after three puffs. Instantaneous flow at 50% of vital capacity (FEF50) decreased significantly with cigarettes high in @entity1239 content, but not so after smoking a low @entity1239 (0.31 mg) cigarette. Instantaneous flow at 75% of vital capacity out (FEF75) increased significantly 30 min after the low @entity1239 cigarette was smoked. A deep inspiration prior to Raw determination reduced by approximately one third the bronchoconstrictor effect of cigarette smoke. All effects were reversible within 30 min, except the delayed effect of the low @entity1239 cigarette on the FEF75. We conclude that the probable site of action of @entity286 smoke is in the large and central airways. The bronchoconstrictor effect rapidly reaches a plateau. A delayed bronchodilation of the small airways observed after smoking the low @entity1239 cigarette might represent a response usually masked by other long-acting components in smoke. We suggest that the airway response to @entity286 smoke is complex and probably a result of several components present in smoke which still have to be identified.
