Effects of electronic cigarette heating coil resistance and liquid nicotine concentration on user nicotine delivery, heart rate, subjective effects, puff topography, and liquid consumption.

Electronic cigarette (ECIG) nicotine delivery and other effects can be influenced by device and/or liquid characteristics and user puffing behavior. One class of ECIGs includes "sub-ohm" devices that incorporate heating coils with resistance less than 1 ohm (Ω), lower than that observed in conventional devices (e.g., ≥1.5 Ω). Relative to conventional ECIGs that operate at ≤10 W, low-resistance coils can be used to increase device power (e.g., 40-300 W). However, little is known about the individual and combined effects of ECIG power, manipulated by coil resistance, and liquid nicotine concentration on ECIG acute effects. Experienced ECIG users ( = 32) completed 4 sessions that differed by ECIG power and coil resistance (40.5 W, 0.5 Ω or 13.5 W, 1.5 Ω) and liquid nicotine concentration (3 or 8 mg/ml). In each session, participants used a 4.5-V Kanger SUBOX ECIG in a 10-puff directed and 60-min ad libitum bout. Nicotine delivery, heart rate, subjective effects, puff topography, and liquid consumption were measured. Nicotine delivery was greatest in the 8mg/ml+0.5Ω condition and lowest in the 3mg/ml+1.5Ω condition. The greatest reduction in abstinence symptoms were observed in the 8mg/ml+0.5Ω condition, although the highest ratings for satisfaction and liking were reported in the 3mg/ml+0.5Ω condition. Use of ECIGs containing 3 mg/ml nicotine liquid resulted in longer and larger puffs and increased puff frequency, though high-power/low-resistance ECIGs resulted in greater consumption of ECIG liquid. ECIG device and liquid characteristics and user puff topography should be considered simultaneously when making regulatory decisions aimed at protecting public health. (PsycInfo Database Record (c) 2020 APA, all rights reserved).