Ethyl Alcohol Study: Top 80 Over 80 Research

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. This gold-standard method for ethyl alcohol quantification ensures precise and legally defensible results.

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.

The analysis frequently detected other volatile compounds alongside the primary ethyl alcohol content.

• 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).
• Isopropyl alcohol (a metabolite of acetone) was detected in 3 cases (maximum concentration was 0.002 g/100mL).

The data paints a clear profile of drivers with extreme ethyl alcohol levels.

• • Gender: 84% male
  • Age: Mean age was 44 years (range 24 to 65 years)
  • Collisions: 73% were involved in motor vehicle collisions and 59% in single MVCs
  • Time of Day: Peak time of driving was between 3:00 p.m. and 6:00 p.m.
  • Day of Week: Driving tends to be evenly distributed throughout week (see graph)

In 10 cases both the hospital and forensic laboratory conducted an alcohol analysis. The results demonstrate a significant variance in ethyl alcohol measurement accuracy.

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. This underestimation of ethyl alcohol concentration has major implications for legal proceedings.

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.

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 ethyl alcohol concentration.

This ethyl alcohol research underscores the critical need for precise forensic toxicology in impaired driving cases. The team at Wigmore on Alcohol leverages this data to inform legal defences and public understanding. For expert consultation on cases involving ethyl alcohol, contact our office.

Contact us for a free forensic evaluation now!

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