To determine whether breath alcohol values (BrAV) attained following mouthwash use pose a realistic threat to the accuracy of blood alcohol determinations by breath analysis.DESIGN
Nonrandomized, open-label trial.SETTING
Outpatient research office.PARTICIPANTS
Ten normal subjects; convenience sample.INTERVENTIONS
Breath alcohol measurements were made 2, 4, 6, 10, and 15 minutes following rinsing of the mouth with Listerine (29.6% alcohol), Scope (18.9% alcohol), and Lavoris (6.0% alcohol) using the Alco-Sensor III intoximeter.MAIN OUTCOME MEASURES
Breath alcohol values over time.RESULTS
Breath alcohol values following mouthwash use decayed exponentially (r >=.98, P<.001) from mean values 2 minutes following mouthwash use of 52.8 mmol/L (240 mg/dL) for Listerine, 37.4 mmol/L (170 mg/dL) for Scope, and 7.9 mmol/L (36 mg/dL) for Lavoris to mean and maximum values after 10 minutes that were well below the usual driving-while-intoxicated range (>=17.6 mmol/L (80 mg/dL)) for all three brands. The nonalcoholic mouthwash ingredients did not significantly affect the BrAVs attained.CONCLUSION
The decay of BrAVs following mouthwash use is sufficiently rapid that mouthwash use would not pose a realistic threat to the accuracy of blood alcohol determinations by breath analysis under normal circumstances. Use of mouthwash immediately prior to breath testing, as might occur in the car or workplace in a mistaken attempt to hide the smell of alcohol or other substances, may, however, significantly increase the measured BrAV.