Smoking and Tobacco Control Monograph No. 7 
breath holding that occurs. Exhalation parameters include exhalation 
volume and duration. These smoking parameters can now be measured 
with technologies that have been developed over the past 20 years. Puffing 
parameters can be measured with a plastic flowmeter, which is attached to 
a pressure transducer; this system measures pressure differences between 
two points in the flowmeter as the cigarette is puffed. Respiratory parameters 
can be measured with noninvasive respiratory inductive plethysmography. 
Essentially, the degree of movement of the chest and abdomen after 
calibration procedures is directly proportional to volumes of smoky air 
inhaled and exhaled. Thus, smoking is a complex behavior with a number 
of discrete, measurable elements. 
WHICH HUMAN It is important to identify which specific elements of 
SMOKING BEHAVIORS smoking behavior influence smoke exposure to focus on 
DETERMINE SMOKE relevant parameters of the FTC testing procedures vs. 
EXPOSURE? human smoking comparison. Stitzer, Zacny, and other 
colleagues over the past several years have conducted three studies (Zacny 
et al., 1986 and 1987; Weinhold and Stitzer, 1989) that have examined 
the relative importance of various smoking topography parameters in 
determining smoke exposure. Smoke exposure is measured by determining 
the amount of carbon monoxide (CO) and nicotine absorbed from smoking 
a single cigarette — these parameters are called CO boost and nicotine boost, 
respectively. 
In these studies, smokers were trained to puff and inhale the cigarette in 
a standardized fashion. The procedure of the standardization is simple: The 
computer involved in the measurement of smoking topography parameters 
can be programmed to beep when a specified level of a smoking parameter 
has been reached. The investigator programs the computer to give the 
smoker feedback as to when to (1) stop puffing (this controls puff volume), 
(2) stop inhaling (this controls inhalation volume), and (3) start exhaling 
(this controls breath-hold duration). After practice with this biofeedback 
system, the smoker is able to reproduce a given smoking pattern that 
includes a fixed puff volume, inhalation volume, and breath-hold duration. 
In the first study (Zacny et al., 1986), an ultralow-yield cigarette was 
smoked in this standardized fashion, and the number of vents that were 
blocked was varied. In this way, the effect of vent blocking on smoke 
exposure could be determined, as measured by CO boost. Either no vents 
were blocked with tape, 50 percent of vents were blocked, or 100 percent of 
the vents were blocked. Smokers took eight fixed-volume puffs (60 mL) from 
the cigarette, inhaled to a certain volume (25 percent of vital capacity), 
held the breath for a certain duration (10 seconds), and then exhaled. Any 
differences in CO boost could be attributed to manipulation of vent blocking 
because other smoking topography parameters were controlled. The authors 
found a systematic increase in CO boost as a function of number of vents 
blocked. In a second study, Weinhold and Stitzer (1989) varied the number 
of puffs (from 8 to 16) taken from a cigarette. CO boost again increased in 
a linear fashion as a function of number of puffs taken. In a third study 
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