Determination of breath alcohol value after using mouthwashes containing ethanol in healthy young adults

To evaluate breath alcohol value and blood alcohol concentration after using mouthwashes containing ethanol in a panel of healthy young adults. To determine zeroing time of these values and if subjects' body mass index or gender influenced it. Breathalyzer test is a practice performed to detect alcohol-impaired-drivers that can be penalized. Sometimes Italian judges revoke the penalty justifying that the presence of residual ethanol in the oral cavity can cause false positive values.

Our study involved 40 young adult volunteers; the cohort was composed of University students aged between 21 and 30 years. They underwent a medical examination to evaluate BMI. We selected four alcoholic mouthwashes available on the market with a different ethanol amount and an ethanol/ water (10/90) mixture as a reference. Breath alcohol concentration values were collected using a portable breathalyzer immediately after the rinse (T0), after 10 and 20 minutes (T10 and T20). We evaluated blood alcohol concentration 5 minutes after the rinse.

All T10 values are lower than 0.5 g/L (Italian BAC driving limit). Differences between average values at T0-T10 are statistically significant (p < 0.05). Correlations between BAV and BMI are not statistically significant respectively at T0 (A: p = 0.54. B: p = 0.96. C: p = 0.93. D: p = 0.53) and T10 (A: p = 0.42. C: p = 0.99. D: p = 0.66). Differences between male and female groups aren't statistically significant (A: p = 0.49; B: p = 0.79; C: p = 0.97; D: p = 0.06).

High BAV values determined at T-0 are a consequence of residual ethanol present in the oral cavity, the zeroing time of these ones (oppure thereof) is very swift. Our study shows that rinsing with an alcoholic mouthwash before undergoing the breathalyzer test does not realistically influence the result.