Impact of vaping ethanol on the roadside field sobriety test in a clinical setting

Abstract

Recent studies have shown that electronic cigarette (e-cig) liquid formulations (e-liquids) can contain ethanol, sometimes in concentrations greater than 20%. Ethanol, rarely listed as an ingredient in e-liquids, is often used as a thinning agent, to dissolve insoluble substances, or added intentionally for consumption. Ethanol in e-liquids has been demonstrated to be aerosolized by e-cigs. Ethanol within the aerosol can be absorbed across mucosal membranes in the mouth, and also within deep lung tissue based on mean-mass particle size diameter. Preliminary Breath Tests (PBT) and Evidentiary Breath Tests (EBT) are conducted to measure ethanol in exhaled breath, with a 15–20 minute wait period, and Standardized Field Sobriety Tests (SFST) evaluate several operant conditions to assess ethanol impairment. Literature on impacts of vaping ethanol is limited. An evaluation to assess the impact of vaping ethanol from e-liquids is essential for law enforcement officers (LEO), medical review officers, ethanol treatment and recovery providers, workplace drug testing, and court mandated drug testing. This study evaluated the impact of inhaled ethanol via vaping on the SFST, PBT, and EBT for thirteen participants using a blind two-by-two experimental design under Virginia Commonwealth University (VCU) IRB HM20015064 and in collaboration with the Virginia Department of Forensic Science, the Center for the Study of Tobacco Products at VCU, VCU Police Department, and City of Richmond Police Department. E-liquids were made by a commercial manufacturer at concentrations of 0% and 20% ethanol. Ethanol concentrations were verified in-house using a Shimadzu HS-20 headspace attached to a Nexis GC-2030 gas chromatograph with dual flame ionization detectors. Stability studies were performed monthly to ensure sample suitability prior to clinical use. Thirteen participants were enrolled into the study based on inclusion and exclusion criteria. They vaped either one or ten puffs of an e-liquid (0% or 20% ethanol). LEOs assessed indicators of impairment by following a study design incorporating SFSTs, PBTs, and EBTs at predetermined intervals. Ethanol concentrations within the e-liquids were determined to be stable at −20 °C for the duration of the study. Positive breath ethanol results ranged from 0.007–0.030 and 0.013–0.043 g/210 dL by PBT immediately after using a 20% ethanol e-liquid when vaping one-puff and ten-puffs, respectively. All subsequent PBTs were negative for ethanol. No ethanol or instrument error was detected by EBT for any vaping scenario, at any timepoint. Impairment was not indicated by SFST. A well-designed human clinical study with robust and relevant collaborations between a crime lab, police departments, and a research university is important to address pertinent questions to forensic science. Breath ethanol concentrations were detectable by PBT immediately after vaping an e-liquid containing 20% ethanol. The results demonstrated the standard wait period of 15–20 minutes employed by LEO before administering a PBT for roadside stops was effective in negating vaping-related false positive breath ethanol results. Vaping ethanol also did not impact SFST results. Results should be considered for other contexts of ethanol testing, such as workplace testing and vehicle ignition interlock systems.