SENSITIVITY OF UPPER AIRWAY REFLEXES IN CIGARETTE SMOKERS - EFFECT OFABSTINENCE

In two studies we have compared the upper airway reflex sensitivity (U ARS) of chronic cigarette smokers with that of non-smokers and also th e effect of different periods of abstinence on UARS in the smoking gro ups. UARS was measured by recording the threshold concentration of dil ute ammonia vapour required to stimulate reflex glottic closure. The f irst study compared UARS in 20 nonsmokers with 20 smokers, followed by another measurement in the smoking group after 24 h of abstinence. In study two, we measured UARS repeatedly over a period of 3-4 weeks in 16 smokers, half of whom had stopped smoking on day 0. Chronic cigaret te smokers were found to have significantly greater UARS compared with non-smokers; the sensitivity was unaltered after 24 h of abstinence b ut was found to reduce over several days, the change commencing betwee n 24 and 48 h, with most achieving a consistent change within 10 days.