A REPEATABLE METHOD FOR DETERMINATION OF CARBOXYHEMOGLOBIN LEVELS IN SMOKERS

Fourteen male smokers participated in ten afternoon test sessions to d etermine the daily variation in expired breath carbon monoxide (CO), a nd whole blood percent carboxyhemoglobin (%COHb), hemoglobin and hemat ocrit levels. Each individual's test session was conducted at approxim ately the same time of day to estimate CO-related measures under relat ively stable conditions. Subjects smoked ad libitum prior to testing. The 'usual brand' cigarette was smoked during the first measurement we ek (sessions 1-5 held on Monday through Friday) and a research cigaret te prototype which primarily heats rather than burns tobacco (TOB-HT) was smoked by 12 of the 14 subjects for 3 weeks prior to and during th e second measurement week (sessions 6-9 held on Tuesday through Friday ), Following the last 'usual brand' measurement session, subjects comp leted 21 days of ad libitum smoking of the TOB-HT cigarette before sta rting sessions 6-9 to allow acclimation to the TOB-HT research cigaret te. Following session 9, 11 of the 14 subjects continued to smoke the TOB-HT cigarette for an additional 3 weeks and then participated in an additional test session (session 10). The data indicate that daily me asurements of afternoon %COHb and expired breath CO values for an indi vidual are reproducible when using this protocol. Carboxyhemoglobin an d expired breath CO levels were elevated by 24.4 and 30.6%, respective ly, after switching to the TOB-HT cigarette. This increase was not due to an increase in the number of cigarettes consumed since the subject s smoked an average of 21 cigarettes prior to the measurement session when smoking either their 'usual brand' or the TOB-HT cigarette.