Does a 10-puff bout reflect natural puffing patterns for electronic nicotine delivery systems?

An important research gap is how users of electronic nicotine delivery systems (ENDS) group puffs together, and whether that pattern accurately reflects the standardized 10-puff procedure often employed in laboratory-based work. Previously defined "puff cluster" parameters were applied to data from our own work and then the patterns compared to those published elsewhere.

For all studies (N=8), the same definition of a puff cluster was used (number of puffs separated by <60 seconds), as was the same cluster categorizations: 1 puff (single), 2-5 puffs (short), 6-10 puffs (medium), or >10 puffs (long). Descriptive analyses included the average frequency, average number of puffs taken, and percent of total puffs/session, for each cluster type. Differences in cluster patterns as a function of pre-session ENDS abstinence and puffing bout length were explored.

Single and small clusters were the most common in 7 of 8 studies; the average number of cluster types was 9.02 (SD=7.55) single clusters, 5.96 (SD=4.02) small clusters, 0.94 (SD=0.74) medium clusters, and 0.49 (SD=0.44) large clusters. Small clusters made up the largest percentage of total puffs within a session (M=37.12%), followed by single puffs (M=28.55%), large clusters (M=17.41%), and medium clusters (M=16.92%). Puff cluster patterns were similar regardless of the pre-session ENDS abstinence requirement and the ENDS puffing bout duration.

Single puffs and small clusters were the predominant cluster types, accounting for accounting for 67.0% of all puffs. The 10-puff bout typically used in laboratory work to standardize product use does not represent naturalistic ENDS puffing.