My colleagues, J.P. Palmentier and Rachel Wallage, at the Centre of Forensic Sciences in Toronto have just published a study that examined the highest BACs found in 80 drivers in Ontario between 1988 and 2007. It has the catchy title of “Top 80 Over 80” which refers to the BAC limit in Canada of 80 milligrams of alcohol in 100 millilitres of blood. The title wouldn’t be nearly as catchy using the American format of .08 g/100mL (i.e. Top 80 over .08).
Typically the blood or serum samples were seized at hospital as part of the police investigation or as a result of a blood demand. All samples were analysed at the Centre of Forensic Sciences in duplicate by headspace gas chromatography using t-butanol as an internal standard.
There were 70 whole blood samples and 10 serum/plasma blood samples analysed. The mean BAC was 428 mg/100mL (range 382-570 mg/100mL). The mean serum alcohol concentration was 532 mg/100mL (range 445-764 mg/100mL). The SACs were converted into a BAC using a conversion ratio between 1.1 and 1.2.
Other Volatiles Detected
Other volatile compounds were detected as well. Methyl alcohol (a sign of alcohol abuse), was detected in 2 cases (0.004 and 0.012 g/100mL). Acetone was detected in 22 cases (maximum concentration was 0.002 g/100mL) and isopropyl alcohol (a metabolite of acetone) was detected in 3 cases (maximum concentration was 0.002 g/100mL).
Characteristics of High BAC Drivers
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84% male
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Mean age was 44 years (range 24 to 65 years)
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73% were involved in motor vehicle collisions and 59% in single MVCs
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Peak time of driving was between 3:00 p.m. and 6:00 p.m.
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Driving tends to be evenly distributed throughout week (see graph)
Comparison of Hospital Results with Forensic Results
In 10 cases both the hospital and forensic laboratory conducted an alcohol analysis as shown in the following Table.
The hospital alcohol analyses were conducted by an enzymatic method and showed lower results than by the gold standard of headspace GC. This may be due in part to the saturation of the enzymes at these high BACs resulting in lower results.
In 2 cases both blood and breath analyses were conducted and the breath tests (Intoxilyzer 5000C) were lower than the actual BAC, due in part to the low calibration ratio of 2100:1 applied by breath alcohol testing instruments.
Conclusions
The conclusion of the authors were:
The BACs reported in this study are sufficient to cause death in the majority of individuals; yet, these individuals were still able to operate a motor vehicle to some degree. Almost half the drivers showed no physical signs of alcohol intoxication. Noteworthy, in our study was a 33 year-old-male with a SAC of 764 mg/100mL, which represents a BAC equivalent to 637-695 mg/100mL. This BAC represents one of the highest reported in the drinking and driving literature and is approximately eight times the per se limit for driving in Canada and approaches twice the concentration typically associated with alcohol-induced fatalities. Cases where hospital analysis or breath testing was undertaken in addition to alcohol analysis demonstrate that at the high levels observed in this study, these methods of alcohol analysis typically underestimated the actual BAC.
References
Palmentier, J-P, F.P., and Wallage, H.R., “Top 80 Over 80: Incidence and Characteristics of the 80 Highest Blood Alcohol Concentrations Obtained in Suspected Impaired Drivers in Ontario”, Canadian Society of Forensic Science Journal, 48(3): 113-121, 2015
Wigmore, J.G., Blog- “Drinking and Driving- Not Just a Night Thing”, October 1. 2013
Wigmore, J.G., Posting, “High BAC Drivers Who Should be Dead”, LinkedIn, November 22nd, 2014
