Results of a proposed breath alcohol proficiency test program

Although proficiency test programs have long been used in both clinical and forensic laboratories, they have not found uniform application in forensic breath alcohol programs. An initial effort to develop a proficiency test program appropriate to forensic breath alcohol analysis is described herein. A total of 11 jurisdictions participated in which 27 modern instruments were evaluated. Five wet bath simulator solutions with ethanol vapor concentrations ranging from 0.0254 to 0.2659 g/210 L were sent to participating programs, instructing them to perform n = 10 measurements on each solution using the same instrument. Four of the solutions contained ethanol only and one contained ethanol mixed with acetone. The systematic errors for all instruments ranged from -11.3% to +11.4% while the coefficient of variations ranged from zero to 6.1%. A components-of-variance analysis revealed at least 79% of the total variance as being due to the between-instrument component for all concentrations. Improving proficiency test program development should consider: (1) clear protocol instructions, (2) frequency of proficiency testing, (3) use lower concentrations for determining limits-of-detection and -quantitation, etc. Despite the lack of a biological component, proficiency test participation should enhance the credibility of forensic breath test programs.     

The elimination rate of mouth alcohol: mathematical modeling and implications in breath alcohol analysis.

Mouth alcohol, if present in high enough concentrations, can falsely bias the accurate measurement of end-expiratory breath alcohol. Mouth alcohol will be eliminated over time, however, and can be modeled with a single term decaying exponential of the form: B0e-kt + C. It is important, however, to determine the model and its parameters when alcohol is already present within the biologic system. Using three individuals as their own controls, mouth alcohol was administered both before and after alcohol consumption followed by breath alcohol analysis performed at approximately 0.5 min intervals. The results showed that both model parameters (B0 and k) are effected and that the asymptotic value (C) is reached much sooner when alcohol already exists in the end-expiratory breath. Considering only three individuals were involved, the forensic-science importance appears to be that, as the end-expiratory breath alcohol concentration increases, the time necessary for the mouth alcohol to decrease to unbiased levels is decreased. Fifteen min of observation time prior to breath alcohol analysis appears to be more than adequate at forensically relevant concentrations.     

Applying a data acquisition system to the analysis of breath alcohol profiles

A breath alcohol profile is generated as a continuous function of time while a person is providing a breath sample. This paper describes a data acquisition system which samples breath alcohol concentrations at discrete intervals during exhalation. The data are stored on disk for later analysis. It is shown that the area under the profile curve for samples preceded by breath-holding is significantly larger than when breathing is normal prior to sample provision (p less than 0.001). The differences between the breath alcohol concentration measurements are also statistically significant (p less than 0.001) for the two different breathing patterns prior to breath exhalation. These results have physiological implications and suggest another means of evaluating breath alcohol profiles.     

Blood alcohol concentration determined from urine samples as a practical equivalent or alternative to blood and breath alcohol tests

The value of urine tests for determining an equivalent blood alcohol concentration in driving under the influence (DUI) enforcement cases is reviewed from a historical, theoretical, and practical perspective. The limits of precision and accuracy that can be ascribed to urine alcohol results are demonstrated through an evaluation of actual case results wherein both a first void and a subsequent urine sample were analyzed and converted to an equivalent blood alcohol concentration (BAC) using a urine to blood conversion factor of 1.3:1.     

New Zealand's breath and blood alcohol testing programs: further data analysis and forensic implications

Paired blood and breath alcohol concentrations (BAC, in g/dL, and BrAC, in g/210 L), were determined for 11,837 drivers apprehended by the New Zealand Police. For each driver, duplicate BAC measurements were made using headspace gas chromatography and duplicate BrAC measurements were made with either Intoxilyzer 5000, Seres 679T or Seres 679ENZ Ethylometre infrared analysers. The variability of differences between duplicate results is described in detail, as well as the variability of differences between the paired BrAC and BAC results. The mean delay between breath and blood sampling was 0.73 h, ranging from 0.17 to 3.1 8h. BAC values at the time of breath testing were estimated by adjusting BAC results using an assumed blood alcohol clearance rate. The paired BrAC and time-adjusted BAC results were analysed with the aim of estimating the proportion of false-positive BrAC results, using the time-adjusted BAC results as references. When BAC results were not time-adjusted, the false-positive rate (BrAC>BAC) was 31.3% but after time-adjustment using 0.019 g/dL/h as the blood alcohol clearance rate, the false-positive rate was only 2.8%. However, harmful false-positives (defined as cases where BrAC>0.1 g/210L, while BAC< or =0.1g/dL) occurred at a rate of only 0.14%. When the lower of duplicate breath test results were used as the evidential results instead of the means, the harmful false-positive rate dropped to 0.04%.     

Comparing roadside with subsequent breath alcohol analyses and their relevance to the issue of retrograde extrapolation.

Driving while intoxicated (DWI) legislation requires proving the critical breath alcohol concentration (BrAC) at the time of driving. With time delayed analysis, retrograde extrapolation is occasionally employed but has several uncertainties associated with it. The present study attempts to address whether subjects actually arrested for DWI are likely to have BrAC values near the time of driving differing largely from those performed at a subsequent time. Selected officers arrested n = 161 subjects where roadside BrAC was determined with Pre-Arrest Breath Test (PBT) devices along with subsequent duplicate evidential analyses followed by an additional PBT analysis. These two sets of duplicates, one with large time interval (mean = 63.5 min.) and one with a 2-3 min difference, were then compared by several statistical methods. The results showing duplicate variability did not differ when the long time interval existed (F = 1.0, P > 0.05). A small but significant decrease in BrAC with respect to time appeared for the duplicate PBT data. Retrograde extrapolation applied to the data employing an assumed 0.015 g/210 l/h yielded a small but significant overestimate of the actual roadside PBT result. Finally, evidentiary analyses performed within 2 h of driving will provide good estimates and certainly not overestimates, of the BrAC existing at the time of driving and it appears that extrapolation may be unwarranted in these cases.     

Evaluation of breath alcohol instruments I. In vitro experiments with Alcolmeter Pocket Model

An Alcolmeter Pocket Model breath alcohol device, based on an electrochemical (fuel cell) oxidation principle for ethanol analysis, has been evaluated under in vitro conditions. The result of a test is displayed on an analogue meter within 20 – 30 seconds after sampling; replicate tests may be made within 3 – 5 minutes. The electrochemical detector used was found to respond to acetaldehyde, methanol, isopropanol and n-propanol vapours besides ethanol, but it was insensitive to acetone vapour. The Alcolmeter response with a 0 – 2.0 mg/ml scale was linearly related to ethanol vapour concentration up to 1.0 mg/ml blood alcohol equivalent concentration; above this level the response was curvilinear, the Alcolmeter reading being too low. The standard deviation of an ethanol vapour determination in vitro was ±0.0175 mg/ml at a mean concentration of 0.902 mg/ml. The accuracy of the device expressed as percent recovery at 0.50, 1.0 and 1.4 mg/ml blood alcohol concentrations was 96.8%, 98.3%, and 88.3%, respectively. When the Alcolmeter was calibrated at 0.50 mg/ml and used occasionally each day over an 18-day period, the drop in initial calibration was 0.01 mg/ml per week.     

Evaluation of breath alcohol instruments II. In vivo experiments with Alcolmeter Pocket Model

The precision and accuracy of an Alcolmeter Pocket Model breath alcohol instrument have been investigated in experiments with human subjects under controlled conditions. The instrument response was zero in all tests with breath samples from alcohol-free subjects. The standard deviations of ethanol determinations in breath were ±0.0722 mg/ml during ethanol absorption and ±0.0416 mg/ml during ethanol elimination. The standard deviation during the elimination phase increased with ethanol concentration in the sample, being ±0.0416 mg/ml on average at a mean concentration of 0.420 mg/ml, corresponding to a coefficient of variation of 9.9%.The blood alcohol estimates using the Alcolmeter were somewhat too high during active absorption of ethanol, and too low during elimination, when a constant blood-breath alcohol ratio of 2100:1 was used to calibrate the instrument. During the elimination phase of ethanol kinetics and at a mean blood alcohol concentration of 0.50 mg/ml, the mean Alcolmeter result was 0.456 ± 0.169 mg/ml with 95% confidence, i.e. varying between 0.287 and 0.625 mg/ml 95 times out of 100 tests at this critical blood alcohol level.     

Psychopathy and instrumental aggression: Evolutionary, neurobiological, and legal perspectives

In the study of aggression, psychopathy represents a disorder that is of particular interest because it often involves aggression which is premeditated, emotionless, and instrumental in nature; this is especially true for more serious types of offenses. Such instrumental aggression is aimed at achieving a goal (e.g., to obtain resources such as money, or to gain status). Unlike the primarily reactive aggression observed in other disorders, psychopaths appear to engage in aggressive acts for the purpose of benefiting themselves. This is especially interesting in light of arguments that psychopathy may represent an alternative life-history strategy that is evolutionarily adaptive; behaviors such as aggression, risk-taking, manipulation, and promiscuous sexual behavior observed in psychopathy may be means by which psychopaths gain advantage over others. Recent neurobiological research supports the idea that abnormalities in brain regions key to emotion and morality may allow psychopaths to pursue such a strategy—psychopaths may not experience the social emotions such as empathy, guilt, and remorse that typically discourage instrumentally aggressive acts, and may even experience pleasure when committing these acts. Findings from brain imaging studies of psychopaths may have important implications for the law.     

Forensic-medical evaluation of toxic hepatitis associated with surrogate alcohol poisoning

Medical cards of 1,116 inpatient victims of surrogate alcohol poisoning and 242 cases of its fatal outcome associated with jaundice were available for analysis form Irkutsk Region and other regions of the Russian Federation in the second half of 2006 and early 2007. The study revealed differences in hepatic lesions depending on the chemical nature of toxicants. Mixtures containing guanidine derivatives caused highly specific irreversible disturbance of bile transport in hepatocytes and biliary capillaries in the absence of cholestasis at the level of biliary ducts. Changes in hepatocytes of different type and genesis appear to be due to other toxic components and may be of use for the establishment of causal relation between hepatic lesions and concrete toxic mixtures.     

A controlled study of the time-course of breath alcohol concentration after moderate ingestion of ethanol following a social drinking session

This paper evaluates the breath alcohol concentration (BrAC), nausea (feeling of being slightly intoxicated) and subjective driving performance after ingesting a moderate dose of alcohol in the presence of a light meal, which intends to approach a social drinking setting. 119 healthy individuals (69 males and 50 females, aged 21.7+/-3.0) ingested three glasses of wine (95mL each) and their BrAC was determined by an Alcotest 7410 at 15, 30, 45, 60, 90 and 120min post-drinking. 46% of females and no male subjects exceeded a BrAC of 0.25mg/L, the legal limit for driving fixed by some Western countries. 53% of the study population felt nausea during the experimental session and 20% self-reported impairment of their driving skills. In both cases these subjective effects were more pronounced in females. The major determinants of mean BrAC were time post-drinking, gender (male) and body mass index (BMI), all these variables being inversely associated. Females and individuals with a BMI lower than 22.5kg/m(2) were at an increased risk of exceeding the legal limit of BrAC. The feeling of nausea was significantly associated with gender (females), the ingestion of up to 2 drinks on weekdays, and having exceeded a BrAC of 0.25mg/L during the experimental study. The main predictor of self-perception of impaired driving skills was the feeling of nausea, followed by a BrAC in excess of 0.25mg/L. In conclusion, both females and subjects with lower BMI are at an increased risk of exceeding the legal limit of BrAC after moderate alcohol consumption resembling a social drinking setting.     

A study concerning the blood/breath alcohol conversion factor Q: concentration dependency and its applicability in daily routine

The conversion factor Q, obtained by division of blood alcohol concentration (BAC) by breath alcohol concentration (BrAC) is a widely discussed topic due to its great variance. By Austrian law, regulations frequently require an estimation of a corresponding BAC by a measured BrAC. It is known that Q depends among other things, on the alcohol kinetic state of the person being tested, which mathematically can be transformed to a dependency on the BrAC. Theoretically calculated Q values per BrAC level form a hyperbola shaped curve, thus decreasing with increasing BrAC values. Applying Austrian forensic standards for BAC and BrAC measurements, these calculations were verified in a study under practical conditions with BAC and BrAC data of 390 individuals. Q decreases from 2629 (+/- 455) for BrAC levels < 0.1 mg/l to 2229 (+/- 160) for a BrAC range of 0.4-0.5 mg/l and increases again to 2428 (+/- 124) for BrAC levels > 0.6 mg/l. Since these results were obtained under realistic practical conditions they can be directly applied in routine forensic expert opinion and can eliminate avoidable variances in the calculation of Q.     

A large-scale study of the relationship between blood and breath alcohol concentrations in New Zealand drinking drivers

Blood alcohol concentrations (BAC) and corresponding breath alcohol concentrations (BrAC) were determined for 21,582 drivers apprehended by New Zealand police. BAC was measured using headspace gas chromatography, and BrAC was determined with Intoxilyzer 5000 or Seres Ethylometre infrared analysers. The delay (DEL) between breath testing and blood sampling ranged from 0.03 to 5.4 h. BAC/BrAC ratios were calculated before and after BAC values were corrected for DEL using 19 mg/dL/h as an estimate of the blood alcohol clearance rate. Calculations were performed for single and duplicate breath samples obtained using the Intoxilyzer (groups I-1 and I-2) and Seres devices (groups S-1 and S-2). Before correction for DEL, BAC/BrAC ratios for groups I-1, I-2, S-1, and S-2 were (mean+/-SD) 2320+/-260, 2180+/-242, 2330+/-276, and 2250+/-259, respectively. After BAC values were adjusted for DEL, BAC/BrAC ratios for these groups were (mean+/-SD) 2510+/-256, 2370+/-240, 2520+/-280, and 2440+/-260, respectively. Our results indicate that in New Zealand the mean BAC/BrAC ratio is 19-26% higher than the ratio of the respective legal limits (2000).     

The development of a sexual abuse severity score: characteristics of childhood sexual abuse associated with trauma symptomatology, somatization, and alcohol abuse

Childhood sexual abuse (CSA) is common and is associated with both mental and physical health problems in adulthood. Using data from an age- and sex-stratified population survey of 600 Olmsted County, Minnesota, residents, a Sexual Abuse Severity Score was developed. The abuse characteristics of 156 CSA respondents were associated with self-reported trauma, somatization, and alcohol use. Characteristics included age of first sexual abuse, more than one perpetrator, degree of coercion, severity of abuse (i.e., attempted intercourse is more severe than fondling), and the number of occurrences. This is one of the few reports to develop a risk summary that quantifies the severity of CSA.