Alcohol calculations and their uncertainty

Risk of motor vehicle collision associated with cannabis and alcohol use among patients presenting for emergency care

BACKGROUND

The objective of this study was to examine the relationship between cannabis and alcohol use and occurrence of motor vehicle collision (MVC) among patients in the emergency department (ED).

METHODS

This was a cross-sectional study of visits to EDs in Denver, CO, Portland, OR, and Sacramento, CA by drivers who were involved in MVCs and presented with injuries (cases) and non-injured drivers (controls) who presented for medical care. We obtained blood samples and measured delta-9-THC and its metabolites. Alcohol levels were determined by breathalyzer or samples taken in the course of clinical care. Participants completed a research-assistant-administered interview consisting of questions about drug and alcohol use prior to their visit, context of use, and past-year drug and alcohol use. Multiple logistic regression was used to estimate the association between MVC and cannabis/alcohol use, adjusted for demographic characteristics. We then stratified participants based on levels of cannabis use and calculated the odds of MVC across these levels, first using self-report and then using blood levels for delta-9-THC in separate models. We conducted a case-crossover analysis, using 7-day look-back data to allow each participant to serve as their own control. Sensitivity analyses examined the influence of usual use patterns and driving in a closed (car, truck, van) versus open (motorcycle, motorbike, all-terrain vehicle) vehicle.

RESULTS

Cannabis alone was not associated with higher odds of MVC, while acute alcohol use alone, and combined use of alcohol and cannabis were both independently associated with higher odds of MVC. Stratifying by level of self-reported or measured cannabis use, higher levels were not associated with higher odds for MVC, with or without co-use of alcohol; in fact, high self-reported acute cannabis use was associated with lower odds of MVC (odds ratio [OR] 0.18, 95% confidence interval [CI] 0.05-0.65). In the case-crossover analysis, alcohol use alone or in combination with cannabis was associated with higher odds of MVC, while cannabis use alone was again associated with decreased odds of MVC.

CONCLUSIONS

Alcohol use alone or in conjunction with cannabis was consistently associated with higer odds for MVC. However, the relationship between measured levels of cannabis and MVC was not as clear. Emphasis on actual driving behaviors and clinical signs of intoxication to determine driving under the influence has the strongest rationale.

Measurement uncertainty of ethyl alcohol concentration in the exhaled breath of drivers and determination of sobriety at the time of incident

The aim of the study was to determine the components of measurement uncertainty in the concentration of alcohol in exhaled breath and to determine the state of sobriety at the time of incident. Based on the literature review and the authors' experience in providing opinions for law enforcement and the judiciary, the influence of various factors on the final interpretation of sobriety state is described on the basis of measurement uncertainty of breath analyzers, uncertainty of retrospective and prospective calculations, and uncertainty related to the conversion of alcohol concentrations detected during breath and blood tests. The paper pays particular attention to interpreting the concentrations of ethanol in exhaled breath close to the legal limits of the state of sobriety and the state after alcohol use, or the state after alcohol use and the state of insobriety. Analyzing the results of an exhaled breath test concerning concentrations close to the values of 0.1 mg/dm3 and 0.25 mg/dm3, it is necessary to take into account the factors affecting the measurements obtained, including the measurement uncertainty of the determination of alcohol in exhaled breath, the processes of absorption, distribution and metabolism of ethyl alcohol, and the possibility of the presence of alcohol lingering in the oral cavity. The incorrect execution of measurements of the tested person's alcohol concentration is also a problematic issue. When determining sobriety state by means of retrospective and prospective calculations, it is important to remember that the uncertainty of the result is affected by a number of factors and depends, among other things, on the information provided by the suspect. Hence, the expert should draw conclusions particularly cautiously and any overestimation or underestimation of the components of uncertainty can lead to erroneous conclusions. Awareness of the uncertainties inherent in the results of a sobriety test or alcohol calculation allows for meaningful interpretation of test results and determination of the sobriety state of the person tested.

A Multicenter, Prospective, Observational Study to Evaluate Ethanol-Induced Symptoms in Patients Receiving Docetaxel Chemotherapy

PURPOSE

Several previous studies and case reports have reported ethanol-induced symptoms in patients receiving anticancer drugs containing ethanol. Most docetaxel formulations contain ethanol as a solvent. However, there are insufficient data on ethanol-induced symptoms when docetaxel-containing ethanol is administered. The primary purpose of this study was to investigate the frequency and pattern of ethanol-induced symptoms during and after docetaxel administration. The secondary purpose was to explore the risk factors for ethanol-induced symptoms.

MATERIALS AND METHODS

This was a prospective, multicenter, observational study. The participants filled out ethanol-induced symptom questionnaire on the day of chemotherapy and the following day.

RESULTS

Data from 451 patients were analyzed. The overall occurrence rate of ethanol-induced symptoms was 44.3% (200/451 patients). The occurrence rate of facial flushing was highest at 19.7% (89/451 patients), followed by nausea in 18.2% (82/451 patients), and dizziness in 17.5% (79/451 patients). Although infrequent, unsteady walking and impaired balance occurred in 4.2% and 3.3% of patients, respectively. Female sex, presence of underlying disease, younger age, docetaxel dose, and docetaxel-containing ethanol amount were significantly associated with the occurrence of ethanol-induced symptoms.

CONCLUSION

The occurrence of ethanol-induced symptoms was not low in patients receiving docetaxel-containing ethanol. Physicians need to pay more attention to the occurrence of ethanol-induced symptoms and prescribe ethanol-free or low-ethanol-containing formulations to high-risk patients.

The performance of saliva test strips for determining ethanol levels, as compared to gas chromatography and breathalyser methods

We set out to determine the performance of the Testi Technologies enzymatic assay saliva ethanol test strips of three different detection levels: 0 g/L, 0.2 g/L and 0.5 g/L, using as the reference method a gas chromatography analyser (GC). Alcohol levels were measured in 104 volunteers at up to three points in time, using up to three test strips per measurement, while gathering blood samples and breathalyser readings in parallel. The plasma alcohol concentrations (PAC) were determined from the plasma samples using GC. The qualitative results of the test strips were compared to the quantitative results from the reference method, as well as the breathalyser readings, and the amount of true and false positive and true and false negative results were classified using predetermined cut-off levels. The best performing test strips were the 0 g/L and the 0.2 g/L strips. The 0 g/L strips had a sensitivity and specificity of 1.00, as false negatives and false positives were not detected. The 0.2 g/L strips had a sensitivity and specificity [95% confidence interval (CI)] of 0.98 (0.96 - 1.00) and 0.83 (0.62 - 1.00) respectively, an accuracy of 0.97 (0.95 - 0.99), and a diagnostic odds ratio of 205.00 (35.33 - 1189.66). The test strips perform their intended purpose of screening for alcohol consumption well, with their great sensitivity as a defining property compared to other testing methods. For them to be able to be implemented in a clinical setting however, further refinement of the tests' characteristics would be required.

Risk assessment of low-dose ethanol in food

A high variety of food contains low doses of ethanol which are sometimes difficult to identify by consumers (adults or children). However, even low doses of ethanol intake raises several toxicological concerns. In the present study, an enzymatic assay and an HS-GC/MS procedure were applied to determine the ethanol levels of 1260 samples from different food categories covering "nonalcoholic" beer, fruit juices/drinks, baked goods, bananas and baby foods. Based on these results, ethanol levels resulting from acute or chronic ethanol intake was calculated using consumption data from the EFSA Comprehensive European Food Consumption Database. Thus, health-based guidance values (HBGV) for ethanol intake were derived for acute or chronic exposure based on the available literature. For acute exposure, very few samples resulted in concerning ethanol uptake levels but following chronic exposure the here derived HBGV level was exceeded in several cases. This is mainly due to the following reasons: (1) certain amounts of ethanol are still tolerated in "nonalcoholic" beer and (2) presence of endogenous produced ethanol in bananas or baked goods via fermentation. Most analysed food samples, however, do not result in elevated ethanol doses linked with a potentially high risk following acute and chronic consumption by adults and children.

Mathematical modeling of the kinetics of multiple ethanol intake

The aim of the study is to construct a mathematical model of the kinetics of multiple ethanol intake based on the kinetic equation of zero-order ethanol elimination with absorption and irrevocable first-order absorption deficiency, as well as its implementation in the format of a computer program. Analytical mathematical modeling of the kinetics of multiple oral administration of ethanol is performed on the basis of this kinetic equation. In the course of modeling, a kinetic summation method was developed that allows to perform a mathematical description of the dynamics of ethanol content in the body in the case of repeated intake of alcoholic beverages of any volume and strength, separated by time intervals of any duration. The developed computational algorithm is implemented in the format of the Alcohol Calculator V 3.0 computer program. The conclusion is made about the expediency of using the developed information and computing technology in the forensic assessment of the quantitative alcohol content in the body at a legally relevant time. 

[Uncertainty estimate in calculation of ingested ethanol]

OBJECTIVE

To develop a method of uncertainty estimate in calculation of ingested ethanol by E. Widmark formula and its realization as a computer program.

MATERIAL AND METHODS

The methodological design of the study was an analytical construction of the equation of uncertainty estimates of the mass of ingested ethanol, obtained on the basis of E. Widmark kinetic model. Mathematical analysis operations were performed independently, as well as using WolframAlfa web application. The computer program code was compiled in the C# programming language using the free version of Microsoft Visual Studio application.

RESULTS

The equation of uncertainty estimate of the mass of ingested ethanol, obtained on the basis of E. Widmark kinetic equation, with standard deviation of the sought value as its measure has been derived. The Alcohol Calculator V 5.0 application was created in the C# programming language. This program implements a complex of computational procedures related to the use of developed uncertainty equation, and allows to determine the confidence error intervals for estimates of ingested ethanol for any probability of error.

CONCLUSION

The obtained equation of uncertainty estimates of the mass of ingested ethanol and the computer application implementing it are recommended for forensic medical evaluation of the kinetics of orally administered ethanol.

Mathematical modeling of the kinetics of a single intake of ethanol

The aim of the study is to construct a kinetic equation of zero-order ethanol elimination with first-order absorption, taking into account the presystemic metabolism of ethanol, with the possibility of determining the errors in estimating the parameters of the model, as well as the implementation of the model in the format of a computer program. Analytical mathematical modeling of the kinetics of a single oral intake of ethanol has been performed. A mathematical model of the kinetics of a single intake of ethanol with its zero-order elimination, absorption and first-order presystemic metabolism has been developed. A method is proposed for estimating the limiting absolute errors of the kinetic parameters of the constructed model based on the summation of the partial contributions of the initial physical quantities. The complex of the developed computational procedures is implemented in the format of the «Alcohol Calculator V 1.0» computer program. The conclusion is made about the expediency of using the developed information and computing technology in the forensic medical expert assessment of acute alcohol intoxication.

Mathematical modeling of the kinetics of a single intake of ethanol

The aim of the study is to construct a kinetic equation of zero-order ethanol elimination with first-order absorption, taking into account the presystemic metabolism of ethanol, with the possibility of determining the errors in estimating the parameters of the model, as well as the implementation of the model in the format of a computer program. Analytical mathematical modeling of the kinetics of a single oral intake of ethanol has been performed. A mathematical model of the kinetics of a single intake of ethanol with its zero-order elimination, absorption and first-order presystemic metabolism has been developed. A method is proposed for estimating the limiting absolute errors of the kinetic parameters of the constructed model based on the summation of the partial contributions of the initial physical quantities. The complex of the developed computational procedures is implemented in the format of the «Alcohol Calculator V 1.0» computer program. The conclusion is made about the expediency of using the developed information and computing technology in the forensic medical expert assessment of acute alcohol intoxication.

What does current science tell us about the accuracy, reliability, and completeness of intoxicated witnesses? A case example of the murder of a prime minister

Generally, the testimony of intoxicated witnesses has been considered relatively unreliable, but recent research has nuanced the knowledge base regarding these vulnerable witnesses.

Revised equations allowing the estimation of the uncertainty associated with the Total Body Water version of the Widmark equation

Widmark calculations are the most commonly used alcohol calculations to estimate a) the amount of alcohol consumed based on blood alcohol concentration (BAC) and b) BACs at a set time after consumption of a known amount of alcohol. These calculations are vital in forensic casework. Previous work has demonstrated that using general error propagation-based equations the variability associated with alcohol calculations can be estimated, but these equations have only been determined for the volume of distribution version of the Widmark equation. However, recent investigations have shown that the total body water (TBW) version of the Widmark equation is more reliable than the version that utilizes the apparent volume of distribution of ethanol. To date, there is no general error propagation equation to determine the variability associated the TBW version of the Widmark equation. Using previously published studies of 185 individuals in which alcohol elimination rate (β) and ethanol's volume of distribution were determined, we have shown that there is a negative correlation (-0.247) between the alcohol elimination rate (β) and TBW. Using these data, we were able to produce equations allowing the estimation of the variability of the results calculated using the TBW version of the Widmark equation. This will allow forensic practitioners to give the best determination of the variability associated with Widmark calculations currently possible.

Just say no to postmortem drug dose calculations

For years, a number of professional groups have warned forensic and clinical toxicologists against calculating an administered dose of a drug based on postmortem blood drug concentrations. But to date, there has been limited information as to how unreliable these dose calculations may actually be. Using amitriptyline as a model drug, this study used empirically determined pharmacokinetic variables for amitriptyline from clinical studies coupled with clinical overdoses (where the individual survived), and death case studies (ascribed to amitriptyline toxicity) in which the dose of amitriptyline was known. Using these data, standard pharmacokinetic equations, and general error propagation, it was possible to estimate the accuracy of calculated doses of amitriptyline, compared with the doses that were consumed. As was expected in postmortem cases, depending on the pharmacokinetic equation used, the accuracy (mean +128% to +2347%) and precision (SD ± 383% to 3698%) were too large to allow reliable estimations of the dose of amitriptyline consumed prior to death based on postmortem blood drug concentrations. This work again reinforces that dose calculations from postmortem blood drug concentrations are unreliable.

Dose-dependent sensorimotor impairment in human ocular tracking after acute low-dose alcohol administration

Key points

Oculomotor behaviours are commonly used to evaluate sensorimotor disruption due to ethanol (EtOH).

The current study demonstrates the dose‐dependent impairment in oculomotor and ocular behaviours across a range of ultra‐low BACs (<0.035%).

Processing of target speed and direction, as well as pursuit eye movements, are significantly impaired at 0.015% BAC, suggesting impaired neural activity within brain regions associated with the visual processing of motion.

Catch‐up saccades during steady visual tracking of the moving target compensate for the reduced vigour of smooth eye movements that occurs with the ingestion of low‐dose alcohol.

Saccade dynamics start to become ‘sluggish’ at as low as 0.035% BAC.

Pupillary light responses appear unaffected at BAC levels up to 0.065%.

Abstract

Changes in oculomotor behaviours are often used as metrics of sensorimotor disruption due to ethanol (EtOH); however, previous studies have focused on deficits at blood‐alcohol concentrations (BACs) above about 0.04%. We investigated the dose dependence of the impairment in oculomotor and ocular behaviours caused by EtOH administration across a range of ultra‐low BACs (≤0.035%). We took repeated measures of oculomotor and ocular performance from sixteen participants, both pre‐ and post‐EtOH administration. To assess the neurological impacts across a wide range of brain areas and pathways, our protocol measured 21 largely independent performance metrics extracted from a range of behavioural responses ranging from ocular tracking of radial step‐ramp stimuli, to eccentric gaze holding, to pupillary responses evoked by light flashes. Our results show significant impairment of pursuit and visual motion processing at 0.015% BAC, reflecting degraded neural processing within extrastriate cortical pathways. However, catch‐up saccades largely compensate for the tracking displacement shortfall caused by low pursuit gain, although there still is significant residual retinal slip and thus degraded dynamic acuity. Furthermore, although saccades are more frequent, their dynamics are more sluggish (i.e. show lower peak velocities) starting at BAC levels as low as 0.035%. Small effects in eccentric gaze holding and no effect in pupillary response dynamics were observed at levels below 0.07%, showing the higher sensitivity of the pursuit response to very low levels of blood alcohol, under the conditions of our study.

Oculomotor behaviours are commonly used to evaluate sensorimotor disruption due to ethanol (EtOH).

The current study demonstrates the dose‐dependent impairment in oculomotor and ocular behaviours across a range of ultra‐low BACs (<0.035%).

Processing of target speed and direction, as well as pursuit eye movements, are significantly impaired at 0.015% BAC, suggesting impaired neural activity within brain regions associated with the visual processing of motion.

Catch‐up saccades during steady visual tracking of the moving target compensate for the reduced vigour of smooth eye movements that occurs with the ingestion of low‐dose alcohol.

Saccade dynamics start to become ‘sluggish’ at as low as 0.035% BAC.

Pupillary light responses appear unaffected at BAC levels up to 0.065%.

Total body water is the preferred method to use in forensic blood-alcohol calculations rather than ethanol's volume of distribution

During the prosecution and defence of drink-driving cases, forensic practitioners are often required to engage in various blood-alcohol calculations, such as whether or not the statutory limit was exceeded (e.g. 80mg/100mL, 0.08g/100mL or 0.80g/L). For this purpose, most forensic scientists utilize the Widmark equation, or some modification thereof, to calculate a person's blood alcohol concentration (BAC) based on information about the amount of ethanol consumed and the pattern of drinking. This equation comes in two main forms; one of which incorporates the apparent volume of distribution of ethanol (V) and the other a person's total body water (TBW). In this study, we utilised two independent data sets, one involving the determination of V for ethanol in 173 men and 63 women, and the other TBW determined for 582 men and 884 women. Those subjects included in the TBW group represented various racial groups (Caucasians, African Americans, Hispanics, Asians and Puerto Ricans), with body mass index (BMI) ranging from 17 to 80kg/m². Both versions of the Widmark equation were evaluated in relation to their accuracy and precision in predicting TBW and/or V using the two most common anthropometric equations; those of Watson et al. and Forrest. Both anthropometric equations exhibited good accuracy (<4.3%) for the prediction of both TBW and V. However, the root mean square error was lower TBW was used for prediction (9.09-12.84%) rather than V (11.72-15.08%). Overall, this study has demonstrated (a) that blood-alcohol calculations are more reliable using TBW rather than V (b) that both equations (Watson et al. and Forrest) are applicable to ethnic groups other than Caucasians and (c) the Forrest equation predicts TBW in men and women with BMI from 17 to 35kg/m² and that the Watson et al. equation works for those with more extreme BMI; females (17-80kg/m²) and males (17-67kg/m²).

The impact of total body water on breath alcohol calculations

Due to a legislative amendment in Austria to determine breath alcohol (BrAC) instead of blood alcohol (BAC) in connection with traffic offences, many results of blood alcohol calculations were simply converted using distinct conversion factors. In Austria, the transformation of BAC to BrAC was carried out by using a factor of 1:2000, which, however, is commonly known to be too low. Noticing the great demand for a calculation method that is not exclusively based on blood alcohol, a formula for calculating breath alcohol based on blood alcohol was published in 1989, but in which the body surface area (BSA) was considered the most important influencing variable. In order to refine this new method, a liquor intake experiment was conducted combined with measurements of total body water (TBW) as an additional variable, using hand to foot bioelectrical impedance assessment (BIA). The test group comprised 37 men and 40 women to evaluate the accuracy of TBW and BSA as an individual parameter for alcohol concentration. The correlation coefficient of BrAC with TBW was constantly higher than with BSA (maximum = 0.921 at 1 h and 45 min after cessation of alcohol intake). These results are valid for both men and women as well as in a gender independent calculation. Hence, for an accurate back calculation of BrAC adjusted values of eliminations rates had to be found. This study describes mean elimination rates of BrAC for both men (0.065 ± 0.011 mg/L h⁻¹) and women (0.074 ± 0.017 mg/L h⁻¹). As previously shown women displayed a significantly higher elimination rate than men (p = 0.006).

Uncertainty in Widmark calculations: ABV variation in packaged versions of the most popular beers in the UK

Forensic practitioners regularly use the Widmark equation to determine theoretical blood alcohol concentrations for use in cases involving alcohol. It is important with these calculations to determine the uncertainty associated with any result. Previous work has investigated the uncertainty in percent alcohol by volume (%ABV) from beers produced by small independent breweries in the UK but did not study the top selling beers in the UK. The top selling lagers and ales/bitters in the UK were identified by sales volume and the %ABV determined. These data was then used to determine the percent coefficient of variation (%CV) that should be used by forensic practitioners when constructing alcohol technical defence reports for use in forensic cases. These samples, from what may be described as 'big' brewers, were determined to have a smaller root mean square error (RMSE) (±0.1%v/v, n = 35), and %CV than those previously reported for beers produced by small, independent breweries in the UK. The results from this study shows that different RMSE's should be used for %ABV when determining the uncertainty of results from Widmark calculations depending if the drinks consumed have been from either 'big' brewers or small, independent breweries.

The influence of alcohol content variation in UK packaged beers on the uncertainty of calculations using the Widmark equation

It is common for forensic practitioners to calculate an individual's likely blood alcohol concentration following the consumption of alcoholic beverage(s) for legal purposes, such as in driving under the influence (DUI) cases. It is important in these cases to be able to give the uncertainty of measurement on any calculated result, for this reason uncertainty data for the variables used for any calculation are required. In order to determine the uncertainty associated with the alcohol concentration of beer in the UK the alcohol concentration (%v/v) of 218 packaged beers (112 with an alcohol concentration of ≤5.5%v/v and 106 with an alcohol concentration of >5.5%v/v) were tested using an industry standard near infra-red (NIR) analyser. The range of labelled beer alcohol by volume (ABV's) tested was 3.4%v/v - 14%v/v. The beers were obtained from a range of outlets throughout the UK over a period of 12 months. The root mean square error (RMSE) was found to be ±0.43%v/v (beers with declared %ABV of ≤5.5%v/v) and ±0.53%v/v (beers with declared %ABV of >5.5%v/v) the RMSE for all beers was ±0.48%v/v. The standard deviation from the declared %ABV is larger than those previously utilised for uncertainty calculations and illustrates the importance of appropriate experimental data for use in the determination of uncertainty in forensic calculations.

Effects of a stand-alone web-based electronic screening and brief intervention targeting alcohol use in university students of legal drinking age: A randomized controlled trial

BACKGROUND

Many intervention efforts targeting student drinking were developed to address US college students, which usually involves underage drinking. It remains unclear, if research evidence from these interventions is generalizable to university and college students of legal drinking age, e.g., in Europe.

OBJECTIVE

To evaluate the effectiveness of a translated and adapted version of the eCHECKUP TO GO, applied as stand-alone web-based electronic screening and brief intervention (e-SBI), in German university students at risk for hazardous drinking.

METHODS

A fully automated web-based two-arm parallel-group randomized controlled trial was conducted. Participants were randomized to an e-SBI or assessment-only (AO) condition. The current paper analyzed students with baseline AUDIT-C scores ≥3 for women and ≥4 for men (sample at baseline: e-SBI [n=514], AO [n=467]; 3-month follow-up: e-SBI [n=194], AO [n=231]; 6-month follow-up: e-SBI [n=146], AO [n=200]). The primary outcome was prior four weeks' alcohol consumption. Secondary outcomes were frequency of heavy drinking occasions, peak blood alcohol concentration, and number of alcohol-related problems.

RESULTS

Mixed linear model analyses revealed significant interaction effects between groups and time points on the primary outcome after 3 and 6months. Compared to students in the AO condition, students in the e-SBI condition reported consuming 4.11 fewer standard drinks during the previous four weeks after 3months, and 4.78 fewer standard drinks after 6months. Mixed results were found on secondary outcomes.

CONCLUSIONS

The results indicate that evidence on and knowledge of web-based e-SBIs based on US college student samples is transferable to German university students of legal drinking age. However, knowledge of what motivates students to complete programs under voluntary conditions, although rare, is needed.

Improving uncertainty in Widmark equation calculations: Alcohol volume, strength and density

The Widmark equation is probably the most commonly used calculation for medicolegal purposes. Recently the National Research Council (USA) and the Forensic Science Regulator (UK) have called for the uncertainty of all results to be given with all forensic measurements and calculations. To improve the uncertainty of measurement of results from Widmark calculations we have concentrated on the uncertainties of measurement involved in the calculation of amount of alcohol, that of the volume of alcohol, the concentration of alcohol and the density of alcohol as previous studies have investigated some of the other factors involved. Using experimental studies, the scientific literature and legal statutes, we have determined revised and improved uncertainties of the concentration of ethanol for Widmark calculations for both the USA and UK. Based on the calculations that we have performed we recommend the use of Monte Carlo Simulation for the determination of uncertainty of measurement for Widmark Calculations.