D Grubb

Lund University, Lund, Skåne, Sweden

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Publications (5)11.05 Total impact

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    ABSTRACT: The presence of mouth alcohol (MA) during alcohol breath test for law enforcement is the most common cause of falsely high breath alcohol concentrations (BrAC). A fast and reliable test for detection of MA roadside at the scene of the act would facilitate the police efforts for proper prosecution. A tentative technique to use orally exhaled water vapour as a reference gas to position the origin of alcohol was validated. BrAC and water vapour concentration (WVC) were simultaneously measured as a known MA component was added to subjects with existing blood alcohol. In the absence of MA, water always precedes alcohol in a volumetric expirogram. In the presence of MA this relationship reversed. A scatterplot of WVC versus BrAC from similar fractional exhaled volumes illustrates how their relative positions change by MA. A deviation area (DA) between the scatterplot curve and a fictitious linear relationship was defined as a measurement of MA. The accuracy and cut-off level of the DA to detect MA were determined with receiver operating characteristic (ROC) curve analysis. The area under the ROC curve (AUC) was 0.95 (95% CI 0.90-1.0), indicating excellent discriminatory ability. The optimal cut-off for DA to discriminate between MA ≥0.010mg/L (1μg/100ml, 0.002g/210L) or lack of MA was -0.35, with a sensitivity of 0.91 and specificity of 0.95. Analysis of BrAC in relation to WVC is a practical method to detect and confirm MA contamination with high reliability. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    No preview · Article · Jan 2015 · Forensic Science International

  • No preview · Article · Sep 2012 · Forensic science international
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    L Lindberg · D Grubb
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    ABSTRACT: The breath alcohol concentration (BrAC) standardized to the alveolar water vapour concentration has been shown to closely predict the arterial blood alcohol (ethanol) concentration (ABAC). However, a transient increase in the ABAC/BrAC ratio has been noted, when alcohol is absorbed from the gastrointestinal tract (absorption phase) and the ABAC rapidly rises. We analysed the plot of simultaneously recorded alcohol, water vapour and CO(2) against exhaled volume (volumetric expirogram) for respiratory dead space volume (VD), cumulative gas output and phase III slope within one breath to evaluate whether changes in the BrAC profile could explain this variability. Eight healthy subjects performed exhalations through pre-heated non-restrictive mouthpieces and the concentrations were measured by infrared absorption. In the absorption phase, the respiratory VD of alcohol was transiently increased and the exhaled alcohol was displaced to the latter part of the expirogram. In the post-absorption phase, the respiratory VD for alcohol and water vapour was stable and always less than the respiratory VD for CO(2), indicating that the first part of the exhaled alcohol and water originated from the conducting airway. The position of the BrAC profile between water vapour and CO(2) in the post-absorptive phase indicates an interaction within the conducting airway, probably including a deposition of alcohol onto the mucosa during exhalation. We conclude that the increase in the ABAC/BrAC ratio during the absorption phase of alcohol coincides with a transient increase in respiratory VD of alcohol and a delay in the appearance of alcohol in the exhaled air as the exhalation proceeds compared with the post-absorption phase.
    Preview · Article · Jun 2012 · Journal of Breath Research
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    ABSTRACT: A novel breath-alcohol analyzer based on the standardization of the breath alcohol concentration (BrAC) to the alveolar-air water vapour concentration has been developed and evaluated. The present study compares results with this particular breath analyzer with arterial blood alcohol concentrations (ABAC), the most relevant quantitative measure of brain alcohol exposure. The precision of analysis of alcohol in arterial blood and breath were determined as well as the agreement between ABAC and BrAC over time post-dosing. Twelve healthy volunteers were administered 0.6g alcohol/kg bodyweight via an orogastric tube. Duplicate breath and arterial blood samples were obtained simultaneously during the absorption, distribution and elimination phases of the alcohol metabolism with particular emphasis on the absorption phase. The precision of the breath analyzer was similar to the determination of blood alcohol concentration by headspace gas chromatography (CV 2.40 vs. 2.38%, p=0.43). The ABAC/BrAC ratio stabilized 30min post-dosing (2089±99; mean±SD). Before this the BrAC tended to underestimate the coexisting ABAC. In conclusion, breath alcohol analysis utilizing standardization of alcohol to water vapour was as precise as blood alcohol analysis, the present "gold standard" method. The BrAC reliably predicted the coexisting ABAC from 30min onwards after the intake of alcohol.
    No preview · Article · Sep 2011 · Forensic science international
  • D. Grubb · L. Lindberg
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    ABSTRACT: Mouth alcohol (MA) is a potential source of error in alcohol breath-testing. Although utilized commercially for MA-detection, the exhalation profile of breath samples containing MA has not been systematically studied before. To characterize the exhalation profile of MA, volumetric expirograms of single-exhalations containing MA were examined. In addition, to explain reports of unusual slow elimination of MA and a suggested influence of blood alcohol on MA elimination, we tested whether MA is distributed to a second compartment by mathematical modelling. Eight subjects rinsed their mouths with alcohol without swallowing, before and after alcohol were administered directly into their stomachs. Breath samples were provided through a low airflow-restricted mouth piece into an analyzer with a sampling frequency of 33 Hz. Mouth alcohol caused an early concentration peak in air from the oral cavity, followed by a continuous contamination of the passing deep lung air which, at the end of the exhalation, exhibited a second, late, concentration peak. In the presence of blood alcohol, however, the distinctive peak features of the profile were absent despite that the breath samples contained MA, making the exhalation profile an unreliable tool for MA detection. Mouth alcohol is probably not distributed to a second compartment to an extent that is of any forensic importance.
    No preview · Article · Mar 2011 · Blutalkohol