[RA-07] Ethanol level and hip flask defence
Department of Forensic Medicine, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Driving under influence (DUI) of alcohol is the common issue in forensic toxicology. In Thailand, blood alcohol concentration (BAC) at 50 mg/dL and 20 mg/dL are statutory limits for general people and people under 20 years old, respectively. However, the time of obtaining blood sample is usually delayed from the time of driving. In addition, alleged drivers can claim that they consumed alcohol after traffic accidents. This claim of post-driving consumption is so-called hip flask defence. Thus, back alcohol calcolation is used to determine BAC at the time of driving based on Widmark's equation and alcohol elimination rate. There are some challenges in back alcohol calcolation. Firstly, alcohol elimination rate follows zero-order kinetics and alcohol elimination rate is averagely accepted as 15 – 20 mg/dL per hour. However, there are some variations in alcohol elimination rates. Secondly, back alcohol calcolation requires the calcolation for Widmark's factor (r) and r comes out in range. Finally, some factors affect alcohol absorption and lead to variations in maximal blood alcohol concentrations used for calcolation. Thus, medical opinions in back alcohol calcolation shoold be carefolly provided.
Keywords: blood alcohol concentration; driving under influence; Widmark's equation