Estimation Of Blood Alcohol Concentration Research Articles

The Impact of Acetic Acid on Measuring Ethanol Concentrations in Water and Human Serum Using Short-Wave Infrared Spectroscopy.

Ethanol intoxication, although an elemental part of life in many places around the world, still presents several issues associated with excessive consumption. These issues range from drunk driving, violence, and antisocial behavior to self-harm, all exerting an increased cost on the society. Monitoring of intoxication levels can help to limit the impact of these issues by preventing the use of automobiles or heavy machinery and personal monitoring. Previous works on noninvasive measurement of ethanol tissue concentration for estimation of blood alcohol concentration (BAC) performed worst during the first hour of intoxication. Gas chromatography research of intoxication shows that levels of acetic acid rise together at a similar rate as those of ethanol after initial imbibement. In this research, short-wave infrared (SWIR) spectroscopy was utilized with the aim of establishing the interaction between ethanol and acetic acid in water and serum mixtures. The most consistent and clear correlation between ethanol and acetic acid was recorded at 2262 and 2302 nm wavelengths. Partial least-squares (PLS) analysis indicates that the most effective region for consideration in measurement of ethanol is the therapeutic window four (IV) due to high variance in vibration of carbon bonds. The behavior of spectra at different concentration ranges was examined and described in detail in relation to the consequence of alcohol measurement. The investigation concluded that ethanol shows distinctive regions of absorbance at wavelengths of 2262 and 2302 nm, with variations arising from increasing concentrations of acetic acid, whilst also showing that therapeutic window four is amongst the most influential regions of the spectrum for SWIR.

Effect of alcohol swabbing of venepuncture site on blood alcohol estimation: A literature review

Estimation of blood alcohol concentration is one of the very important investigations in medico-legal cases dealing with drink and driving, alcohol toxicity etc. There are many factors which may influence estimation of blood alcohol concentration of an individual. One of these factors is thought to be application of alcohol containing swab at venepuncture site, prior to collection of blood for alcohol estimation, either by gas chromatography or by enzymatic assay. Alcohol content of swab, either plain ethanol or iso-propyl alcohol, is said to influence blood alcohol estimation, to a significant extent, is a very common information rather misinformation given to all medical practitioners worldwide. Unfortunately, Courts of Law, in India also have to believe on this, and in many cases defence try to create benefit of doubt, using this information. It is commonly learnt and taught to Medical graduates, that while collecting blood samples from an individual for Blood Alcohol estimation, spirit swab should not be used for cleaning area of venepuncture. This is due to reason believed so far, that alcohol swabbing of venepuncture site can alter Blood Alcohol Estimation significantly. However there is no any study advocating this theory. Moreover review of literature pertaining to this subject has shown studies, which tend to prove that this concept is nothing but a myth and one has to be very particular to prove alteration in blood alcohol concentration due to alcohol swabbing of venepuncture site. Secondly, the literature and curricular statements in Forensic Medicine, which is written long back, needs exhaustive changes, and should be more evidence based.

Validation of hair ethyl glucuronide using transdermal monitoring and self-reported alcohol use in women of childbearing potential.

AimThe present study aimed to evaluate the validity of hair ethyl glucuronide concentrations compared with transdermal alcohol concentration and self‐reported alcohol use.MethodsThis trial included 25 adolescent and young adult females, aged 16‐24, who reported at least one heavy drinking episode (≥4 drinks) in the two weeks prior to baseline. All participants were asked to wear an alcohol biosensor over a one‐month prospective study. Detailed self‐report of drinking behaviors was assessed weekly. Estimates of blood alcohol concentration were computed from self‐report data using the National Highway and Transportation Safety Administration equation. Transdermal alcohol concentration and estimated blood alcohol concentration data were categorized into at‐risk (>0.05 g/dL alcohol) and high‐risk (>0.08 g/dL alcohol) drinking events. Hair ethyl glucuronide concentration, total number of drinking events, moderate (>0.05 g/dL) and high level (>0.08 g/dL) of transdermal alcohol concentration, and estimated blood alcohol concentration drinking events were analyzed with Spearman's rank correlation test for validity comparisons.ResultsNo significant correlations were found between hair ethyl glucuronide values and total number, and moderate or high levels of detected drinking events by estimated blood alcohol concentration or transdermal alcohol concentration. Total number of drinking events detected and number of drinking events >0.08 g/dL using estimated blood alcohol concentration and transdermal alcohol concentration methods were significantly correlated with each other (respectively, R = .33, P < .05; R = .42, P < .05).ConclusionOur findings indicate that, due to the number of false negatives, hair ethyl glucuronide concentrations should be used with caution for monitoring abstinence from alcohol use.

Estimation of Blood Alcohol Concentration From Smartphone Gait Data Using Neural Networks.

Driving is a dynamic activity, which requires quick reflexes and decision making in order to respond to sudden changes in traffic conditions. Alcohol consumption impairs motor and cognitive skills, and causes many driving-related accidents annually. Passive methods of proactively detecting drivers who are too drunk to drive in order to notify them and prevent accidents, have recently been proposed. The effects of alcohol on a drinker's gait (walk) is a reliable indicator of their intoxication level. In this paper, we investigate detecting drinkers' intoxication levels from their gait by using neural networks to analyze sensor data gathered from their smartphone. Using data gathered from a large controlled alcohol study, we perform regression analysis using a Bi-directional Long Short Term Memory (Bi-LSTM) and Convolutional Neural Network (CNN) architectures to predict a person's Blood Alcohol Concentration (BAC) from their smartphone's accelerometer and gyroscope data. We innovatively proposed a comprehensive suite of pre-processing techniques and model-specific extensions to vanilla CNN and bi-LSTM models, which are well thought out and adapted specifically for BAC estimation. Our Bi-LSTM architecture achieves an RMSE of 0.0167 and the CNN architecture achieves an RMSE of 0.0168, outperforming state-of-the-art intoxication detection models using Bayesian Regularized Multilayer Perceptrons (MLP) (RMSE of 0.017) and the Random Forest (RF), with hand-crafted features. Moreover, our models learn features from raw sensor data, obviating the need for hand-crafted features, which is time consuming. Moreover, they achieve lower variance across folds and are hence more generalizable.

Feasibility and reliability of continuously monitoring alcohol use among female adolescents and young adults.

Transdermal alcohol sensors allow objective, continuous monitoring and have potential to expand current research on adolescent and young adult alcohol use. The purpose of this manuscript is to evaluate the feasibility and reliability of transdermal alcohol sensor use among female adolescents as compared to female young adults. This trial included 59 female adolescents and young adults aged 14-24 years who reported drinking during the previous month. All participants were asked to wear a Giner Wrist Transdermal Alcohol Sensor (WrisTAS)-7 over a 1 month prospective study. Participants came to the research lab weekly to complete a detailed self-report of behaviours, including day of drinking events, amounts and types of alcohol use and length of drinking events. Estimates of blood alcohol concentration (eBAC) were computed from self-report data using the Matthew and Miller, NHTSA and Zhang equations. Daily transdermal alcohol concentration (TAC) peaks and calculated eBAC peak data were analysed with paired-samples t-tests and repeated measures correlations for validity comparisons. All participants (100%, n=59) completed the trial, however, two participants were removed due to greater than 50% of missing transdermal alcohol sensor data. Of the 57 participants, the data included 1,722 days of continuous alcohol monitoring. Missing data was recorded more frequently among female adolescents at about (11.78%) as compared to female young adults (8.59%; χ2 =-18.40, P < 0.001). Participant self-report of drinking occurred with greater frequency (374 events) than detected by the WrisTAS transdermal alcohol sensors (243 events). On days when self-report and sensor data indicated a drinking event, participants' eBAC was moderately correlated with TAC, after accounting for repeated measures. This study finds that transdermal alcohol sensors are moderately reliable when sensor data is paired with self-report. This objective data collection method may improve the ability to collect alcohol curves among adolescents.

Assessment of Alcohol Use in the Natural Environment.

The current article critically reviews 3 methodological options for assessing drinking episodes in the natural environment. Ecological momentary assessment (EMA) typically involves using mobile devices to collect self-report data from participants in daily life. This technique is now widely used in alcohol research, but investigators have implemented diverse assessment strategies. This article focuses on "high-resolution" EMA protocols that oversample experiences and behaviors within individual drinking episodes. A number of approaches have been used to accomplish this, including using signaled follow-ups tied to drinking initiation, asking participants to log entries before and after individual drinks or drinking episodes, and delivering frequent signaled assessments during periods of the day when alcohol use is most common. Transdermal alcohol sensors (TAS) are devices that are worn continuously and are capable of detecting alcohol eliminated through the skin. These methods are appealing because they do not rely upon drinkers' self-report. Studies using TAS have been appearing with greater frequency over the past several years. New methods are making the use of TAS more tractable by permitting back-translation of transdermal alcohol concentration data to more familiar estimates of blood alcohol concentration or breath alcohol concentration. However, the current generation of devices can have problems with missing data and tend to be relatively insensitive to low-level drinking. An emerging area of research investigates the possibility of using mobile device data and machine learning to passively detect the user's drinking, with promising early findings. EMA, TAS, and sensor-based approaches are all valid, and tend to produce convergent information when used in conjunction with one another. Each has a unique profile of advantages, disadvantages, and threats to validity. Therefore, the nature of the underlying research question must dictate the method(s) investigators select.

Estimated blood alcohol concentrations achieved by consuming supersized alcopops

ABSTRACTBackground: Producers of supersized alcopops have ignored requests from a number of state attorneys general to reduce the alcohol concentration in these products. To the contrary, new flavor options have since been released that contain even greater alcohol content so that some alcopop products now contain 5.5 standard alcoholic drinks in a single-serving can. Though alcohol content of supersized alcopops has risen, little attention has been paid to the blood alcohol concentration (BAC) level consumers can expect to achieve from drinking these products. Objectives: To estimate BAC levels expected from consuming one or two cans of supersized alcopop, relative to beer. Methods: Median weight data from the National Health and Nutrition Examination Survey were used in Matthews and Miller’s (1979) BAC estimation formula. Results: Consuming a single supersized alcopop over the course of 2 hours can put youth and young adults well over the legal per se driving limit of 0.08 g/dL. Consuming two cans puts them at risk of alcohol poisoning. Conclusions: Estimates provided here show that supersized alcopop consumers obtain dangerously high BAC levels. Reductions in the alcohol content of supersized alcopops should be an urgent priority for public health policy and law.

Predrinking, alcohol use, and breath alcohol concentration: A study of young adult bargoers.

Predrinking (preloading, pregaming) has been found to be related to alcohol use and intoxication. However, most research relies on estimates of blood alcohol concentration and does not control for usual drinking pattern. We assessed whether predrinking was associated with subsequent alcohol consumption and breath alcohol concentration (BrAC) among 287 young adult bargoers (173 men [60.3%], Mage = 21.86 years, SD = 2.55 years) who were recruited in groups in an entertainment district of a midsized city in Ontario, Canada. We also examined whether predrinking by other group members interacted with individual predrinking in relation to amount consumed/BrAC. Adjusting for nesting of individuals within groups in hierarchical linear models, predrinkers were found to consume more drinks in the bar district and over the entire night compared to nonpredrinkers and had higher BrACs at the end of the night controlling for drinking pattern. A group- by individual-level interaction revealed that individual predrinking predicted higher BrACs for members of groups in which at least half of the group had been predrinking but not for members of groups in which less than half had been predrinking. This study confirms a direct link of predrinking with greater alcohol consumption and higher intoxication levels. Group- by individual-level effects suggest that group dynamics may have an important impact on individual drinking. Given that predrinking is associated with heavier consumption rather than reduced consumption at the bar, initiatives to address predrinking should include more effective policies to prevent intoxicated people from entering bars and being served once admitted.

Estimation of blood alcohol concentration in deaths due to roadside accidents

Like any other disease, accidents too are caused by interaction between agent, host, and environment. Human factors include age, (accidents most common between 10 and 24 years), sex, education, medical conditions (heart attack, impaired vision), fatigue, influence of alcohol and other drugs, lack of bodily protection (like helmets, seat belts) and psychosocial factors like lack of experience, impulsiveness, aggressiveness, defective judgment and delay in decisions. Drunken driving is an important risk factor in causing accidents. This study was focused on the status of alcohol consumption in relation with roadside accidents in northern India in the region of Amritsar. The present study was carried out in 100 cases alleged to have died of roadside accident and brought to the mortuary attached to the Department of Forensic Medicine and Toxicology, Government Medical College, Amritsar for autopsy examination. Blood samples were collected from the femoral vein and were tested for the presence of alcohol with steam distillation and titration method using potassium dichromate and sulfuric acid. In the present study, 23% of the fatal driver/pedestrian victims of roadside accidents were found to have consumed alcohol before accident. Most of the victims of road accident were from the age group 21–30 and 31–40 years. Most of the accidents occurred on straight roads instead of bends or intersections, more during daytime and weekends. 57% of the blood alcohol positives were between 100 mg% and 149 mg%. Majority of the victims of roadside accidents were motorcyclists and the striking vehicles were trucks and buses causing head & neck injuries in most of the victims. Death occurred within a few minutes in most of the cases.

How drunk am I? Misperceiving one's level of intoxication in the college drinking environment.

One effective event-level index that can assist in identifying risky intoxication levels among college students is blood alcohol concentration (BAC). Despite widespread exposure to BAC information, doubt exists as to whether American college students can accurately estimate their own BAC level or drinking behaviors while intoxicated. This study assessed whether students can accurately guesstimate their BAC level and drinking behaviors used to estimate BAC (eBAC) while drinking in social college settings. Participants (N = 225; 56.4% male) consisted of emerging adults attending either a 2- or 4-year college who had at least one alcoholic drink within the 2 hr before assessment. Participants were approached at night when returning from parties and/or alcohol-serving establishments. They completed an initial questionnaire, gave a breath sample to assess breath alcohol content, and then completed an online follow-up questionnaire within 48 hr of baseline assessment. Participants at lower levels of intoxication tended to slightly overestimate their BAC level, while those at higher levels tended to markedly underestimate their BAC level. In addition, discrepancies among breath alcohol content, guesstimated BAC, and eBAC were found as a function of gender. Lastly, differences in eBAC scores did not differ when drinking behaviors were obtained via in vivo versus retrospective methodology. Findings suggest that college students generally have difficulty assessing their BAC level and drinking behaviors while drinking in the college social setting. This study offers particular insight for research relying on estimates of BAC as well as interventions utilizing BAC education.

Impact of Providing Drinkers With “Know Your Limit” Information on Drinking and Driving: A Field Experiment

Given that most effective alcohol harm-reduction laws specify the blood alcohol concentration (BAC) that constitutes illegal behavior (e.g., the .08% breath alcohol concentration legal limit), interventions that allow drinkers to accurately estimate their BACs, and thus better assess their risk, have potential importance to long-term driving-under-the-influence prevention efforts. This study describes a field experiment designed to test the impact on drinking of providing "Know Your Limit" (KYL) BAC estimation cards to individuals in a natural drinking environment. We randomly sampled 1,215 U.S. residents as they entered Mexico for a night of drinking, interviewed them, and randomly assigned them to one of six experimental conditions. Participants were reinterviewed and breath-tested when they returned to the United States. The experimental conditions included providing generic warnings about drinking and driving, giving out gender-specific BAC calculator cards (KYL cards), and providing incentives to moderate their drinking. Cueing participants about the risks of drunk driving resulted in significantly lower BACs (relative to control) for participants who indicated that they would drive home. Providing KYL matrixes did not reduce BACs, and, in fact, some evidence suggests that KYL cards undermined the effect of the warning. KYL information does not appear to be an effective tool for reducing drinking and driving. Implications for prevention and future research are discussed.

Estimation of blood alcohol concentration by horizontal attenuated total reflectance–Fourier transform infrared spectroscopy

Numerous methods like distillation followed by iodometric titrations, gas chromatograph (GC)–flame ionization detector, gas chromatograph–mass spectrophotometer, GC-Headspace, Breath analyzer, and biosensors including alcohol dehydrogenase (enzymatic) have been used to determine blood alcohol concentration (BAC). In the present study, horizontal attenuated total reflectance–Fourier transform infrared spectroscopy had been used to determine BAC in whole blood. The asymmetric stretching frequency of C–C–O group of ethanol in water (1,045 cm −1) had been used to calculate BAC using Beer's Law. A seven-point calibration curve of ethanol was drawn in the concentration range 24–790 mg dL −1. The curve showed good linearity over the concentration range used ( r 2 = 0.999, standard deviation = 0.0023). The method is accurate, reproducible, rapid, simple, and nondestructive in nature.

The estimation of blood alcohol concentration : Widmark revisited.

Expert witnesses and others involved in toxicology are frequently asked to perform retrograde extrapolation of blood alcohol concentration (BAC) or to estimate BAC based on a proposed drinking scenario. Although many individuals are reluctant to perform these calculations and some jurisdictions expressly prohibit them, a significant number of practitioners routinely estimate BAC based on this type of calculation, using as a basis the fundamental work of Widmark. Although improvements to the Widmark formula and other data pertaining to the pharmacology of alcohol have been published, these improvements are frequently ignored when estimating BAC. This article summarizes five published models for the estimation of BAC and proposes a sixth model that incorporates recent data on the rate of absorption of alcohol from the GI tract into the existing five models. The five improved models can be computerized and used to construct comparative snapshots of the BACs calculated by the different algorithms. This will allow practitioners to provide a more balanced picture of the variability in BAC calculations.

Environmental and Individual Predictors of Error in Field Estimates of Blood Alcohol Concentration: A Multilevel Analysis

Using self-report survey data and measures of breath alcohol concentration (BrAC), this study examined the validity of an estimate of blood alcohol concentration (eBAC). Differences between eBAC and BrAC were modeled to identify sources of error related to survey-derived eBAC. Further, using hierarchical multilevel analyses, environmental event characteristics were examined as sources of eBAC error. College students were interviewed and provided breath samples at randomly selected parties on Friday and Saturday nights. Interviews included items assessing the total number of drinks consumed, duration of drinking event, gender, and weight, which allowed for the calculation of eBAC. Overall, eBACs were inaccurate. Total number of drinks consumed was associated with underestimates of eBAC, whereas time drinking was associated with overestimates of eBAC. Environmental variables, including party size, rowdy behavior, having food present, and observing many intoxicated partygoers, were also associated with eBAC errors. Current self-report survey methodology to calculate eBAC may be insufficient to estimate BAC with any accuracy. Environmental factors associated with the last drinking event for which BAC is being estimated should be considered when calculating eBAC.

Widmark factors for local Chinese in Hong Kong: A statistical determination on the effects of various physiological factors

The Widmark formula has been widely adopted in forensic applications to drink driving cases for the last 70 years. It is known that the amount of alcohol consumed and the body weight of the drinkers are important information for the estimation of blood alcohol concentration (BAC). However, the direct application of the Widmark factors derived from Caucasian to the calculation of BAC for the Chinese population often encounters serious challenges. Owing to this inherent weakness, a thorough analysis to determine the theoretical Widmark factors for the Chinese population, r 0 at the start of drinking and the practical factors, r peak, at peak BAC was conducted. In the present study, other factors such as gender, stomach condition and other physiological conditions are taken into account. The determined theoretical Widmark factors, r 0, for local Chinese male and female are 0.68 and 0.59 (with BAC in the units of weight/volume), respectively, demonstrating the applicability of the Widmark formula to the Chinese population. The practical factors at peak BAC, r peak, were also determined to serve the forensic purpose of refuting the “hip-flask” defence in drink driving cases. Findings show that gender and stomach condition are the key factors that could statistically explain the variability of both r 0 and r peak.

Potential Risks of Providing Drinking Drivers with BAC Information

The objective of this paper is to discuss the benefits and risks of providing drinkers with tools that allow them to estimate their blood alcohol concentration (BAC), and to examine the field usability of one commercially available tool. Drinking and driving laws are specified in terms of the driver's BAC, and there is concern that the absence of a method for drivers to accurately estimate their BAC level limits their ability to determine whether they can drive legally. A number of devices that provide a method for the individual to estimate or measure their BAC have been developed. Although some of these devices—such as the “know your limit” (KYL) cards—have been widely distributed, their effectiveness in encouraging good driving decisions have rarely been tested. This article describes a pilot study on the field usability of the Guardian Angel (GA) personal alcohol test in a field setting. The GA test analyzes saliva samples from drinking and indicates under which BAC category they fall (.00−.04; .04−.08; .08+). The research examined whether drinkers could, in natural drinking environments, correctly administer and interpret the test results. The methodology involves sampling drinkers on a weekend night on and around the grounds of a large West Coast university as they traveled between off-campus parties, bars, and their dorms. They were asked to assess their own intoxication and impairment, then self-administer and interpret the Guardian Angel test. After interpreting the test, participants were asked to reassess their intoxication and impairment levels, and were given a breath BAC test using a calibrated unit. The results revealed that although the majority of drinkers' were able to administer the GA test, their interpretations did not correspond with actual BACs. The interpretations of the GA test produced false-negatives, underestimating actual BACs. Drinkers perceived themselves to be less intoxicated, on average, after interpreting the GA test results. In conclusion, this research addresses potential pros and cons of providing BAC information to drinkers. It underscores the importance of testing BAC estimation tools under field conditions and the potential risks associated with tests that do not produce accurate results.

Field assessment of BAC data to study late-night college drinking.

This field study of late-night college drinking sought to (1) test the ability of the 5+/4+ measure to screen for higher levels of intoxication and (2) examine the relation between estimated and actual blood alcohol concentration (BAC). During a 15-week spring semester, college students returning to their residence halls between 10:00 PM and 3:00 AM on Wednesday through Saturday nights were anonymously interviewed to collect BAC and self-report data (n = 1,020). Although 70.9% had not been drinking on Wednesday nights, a majority of the intercepted students had been drinking on the other three nights. Mean BACs on these three nights were in a moderate range (48 to 51 mg/dl), but the 5+/4+ measure classified many students as heavy episodic drinkers at relatively low BACs. For example, 66.3% of those meeting the 5+/4+ criterion for the night had BACs < 100 mg/dl. Students with BACs ranging from 70 to 90 mg/dl exhibited the greatest accuracy in estimating their BAC; those with lower BACs tended to overestimate their level of intoxication; whereas those with higher BACs tended to underestimate it. Field assessment of student intoxication is an important tool for examining research questions in college drinking. The 5+/4+ measure classifies many college students as heavy episodic drinkers, even though their intoxication level is below conventional thresholds used to define drunkenness. In addition, there is a discernible pattern of BAC estimation in the field that corresponds to intoxication level.

Multiple use one-sided hypotheses testing in univariate linear calibration

Consider a normally distributed response variable, related to an explanatory variable through the simple linear regression model. Data obtained on the response variable, corresponding to known values of the explanatory variable (i.e., calibration data), are to be used for testing hypotheses concerning unknown values of the explanatory variable. We consider the problem of testing an unlimited sequence of one sided hypotheses concerning the explanatory variable, using the corresponding sequence of values of the response variable and the same set of calibration data. This is the situation of multiple use of the calibration data. The tests derived in this context are characterized by two types of uncertainties: one uncertainty associated with the sequence of values of the response variable, and a second uncertainty associated with the calibration data. We derive tests based on a condition that incorporates both of these uncertainties. The solution has practical applications in the decision limit problem. We illustrate our results using an example dealing with the estimation of blood alcohol concentration based on breath estimates of the alcohol concentration. In the example, the problem is to test if the unknown blood alcohol concentration of an individual exceeds a threshold that is safe for driving.

Transdermal Alcohol Measurement for Estimation of Blood Alcohol Concentration

Transdermal Alcohol Measurement for Estimation of Blood Alcohol Concentration

Self-estimates of blood alcohol concentration in drinking-driving context

A total of 72 social drinkers between the ages of 20 and 57 years participated in an ad lib social drinking session. At various intervals throughout the session participants provided estimates of their blood alcohol concentration (BAC) along with breath samples for objective determination of their BAC. Participants were classified into three groups, based on the pattern of their BAC estimation errors — Underestimators, Overestimates, or Mixed Pattern estimators. Underestimators consumed more alcohol and attained higher BACs during the drinking session than the other two groups. Underestimators also rated their level of intoxication significantly lower than other groups and were most likely to judge themselves fit to drive when their actual BAC was in excess of the statutory limit.