Alcohol, its analysis in blood and breath for forensic purposes, impairment effects, and acute toxicity

Abstract

Alcohol (ethanol) is man's favorite recreational drug and the psychoactive substance most often encountered in forensic toxicology casework; impaired driving cases, sexual assaults, and drug intoxication deaths. Because of the legal consequences of a person's blood-or breath-alcohol concentration (BAC or BrAC), the analytical methods used must be accurate, precise, and fit for purpose. The gold standard method for determination of ethanol in blood and other biological specimens is gas-liquid chromatography with flame ionization detector, although some laboratories also use a mass spectrometric detector. Also widely used for legal purposes are breath-alcohol analyzers; at the roadside as screening tests and also as evidence for prosecution of traffic offenders. Evidential instruments determine ethanol in exhaled breath by infrared spectrometry at wavelengths of 3.4 and/or 9.5 μm or by electrochemical oxidation with a fuel-cell detector. The impairment of body functions after drinking alcohol depend on the amount consumed (the dose), the speed of drinking and the BAC reaching the brain. After drinking 1-2 units of alcohol (~16 g ethanol) people become more talkative and feel less inhibited (BAC <50 mg%). Cognitive and psychomotor functions are impaired as BAC reaches 80 mg% and at 150 mg% the signs and symptoms of alcohol intoxication are much more obvious including slurred speech, lack of coordination, confusion, and combativeness. On reaching BACs of 300-400 mg% most people are incapacitated and/or unconscious with slow and shallow breathing and at risk of death from paralysis of respiratory centers in the brain stem.

Can Lipoic Acid Attenuate Cardiovascular Disturbances Induced by Ethanol and Disulfiram Administration Separately or Jointly in Rats?

“…It is assumed that blood alcohol levels (BACs) exceeding 500 mg% can result in death in humans as a result of paralysis of respiratory centers in the brain stem. On the other hand, there are known cases when alcohol produced death in humans at the values of BAC ranging from under 200 mg% to over 600 mg% [14, 15]. Why some people survive high BAC and others do not is an open question.…”

“…In our opinion, it is similar in animals. Jones proposed to consider that when examining deaths due to acute ethanol poisoning, among all other factors, lady luck should not be forgotten [15].…”

Significant decrease in the rate of fatal alcohol poisonings in Finland validated by blood alcohol concentration statistics

“…Forensic medicine textbooks often quote 3 g/kg as the lethal BAC but it can be affected by a variety of factors such as age, gender, body composition and tolerance (Johnson 1985, Heatley and Crane 1990, Koski et al 2002, Jones and Holmgren 2003, Lahti et al 2011, Li et al 2017. The lethal BAC can be lower when, for example, the victim is elderly, suffered from cardiac diseases or aspiration occurred (Thomsen 2014, Saukko et al 2016, Jones 2019. Furthermore, since the irrevocable process leading to respiratory depression starts some time before death (Jones and Holmgren 2003) and alcohol continues to be metabolised until the time of death, BAC measured post-mortem is likely to be lower than the BAC at the time death became inevitable.…”

Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

“…The use of urine is particularly indicated for immune-enzymatic assays, allowing a rapid screening of both compounds and metabolites. The urinary levels of these molecules indicate only exposure to the substances, and do not allow concluding about the exact time of exposure or the likely physiological effects [ 54 , 55 , 58 , 59 ].…”