Background: Many patients seeking emergency care are under the influence of alcohol, which in many cases implies a differential diagnostic problem. For this reason early objective alcohol screening is of importance not to falsely assign the medical condition to intake of alcohol and thus secure a correct medical assessment.Objective: At two emergency departments, demonstrate the feasibility of accurate breath alcohol testing in emergency patients with different levels of cooperation.Method: Assessment of the correlation and ratio between the venous blood alcohol concentration (BAC) and the breath alcohol concentration (BrAC) measured in adult emergency care patients. The BrAC was measured with a breathalyzer prototype based on infrared spectroscopy, which uses the partial pressure of carbon dioxide (pCO(2)) in the exhaled air as a quality indicator.Result: Eighty-eight patients enrolled (mean 45 years, 53 men, 35 women) performed 201 breath tests in total. For 51% of the patients intoxication from alcohol or tablets was considered to be the main reason for seeking medical care. Twenty-seven percent of the patients were found to have a BAC of <0.04 mg/g. With use of a common conversion factor of 2100:1 between BAC and BrAC an increased agreement with BAC was found when the level of pCO(2) was used to estimate the end-expiratory BrAC (underestimation of 6%, r = 0.94), as compared to the BrAC measured in the expired breath (underestimation of 26%, r = 0.94). Performance of a forced or a non-forced expiration was not found to have a significant effect (p = 0.09) on the bias between the BAC and the BrAC estimated with use of the level of CO2. A variation corresponding to a BAC of 0.3 mg/g was found between two sequential breath tests, which is not considered to be of clinical significance.Conclusion: With use of the expired pCO(2) as a quality marker the BrAC can be reliably assessed in emergency care patients regardless of their cooperation, and type and length of the expiration.

The study objective was to evaluate a novel method and technology for unobtrusive determination of breath alcohol in relation to current industrial accuracy standards.The methodology uses carbon dioxide as a tracer gas detected by sensor technology based on infrared spectroscopy.Part one of the investigation was to analyse the performance of hand-held prototype devices and included tests of resolution, unit-to-unit variation during calibration, response to alcohol containing gas pulses created with a wet gas simulator, and cross sensitivity to other substances.In part two of the study, 30 human participants provided 1465 breath tests in both unobtrusive and obtrusive use modes.The results of both parts of the study indicate that the prototype devices exceeded present industrial accuracy requirements.The proposed methodology and technology eliminate the previous contradiction between unobtrusiveness and high accuracy.

Measurement of breath alcohol concentration is strongly influenced by timing and the breathing pattern. In particular, shallow expiration and hyperventilation leads to underestimation of the breath alcohol concentration. In the present study, expirograms of alcohol, water and carbon dioxide were recorded in 30 healthy individuals at various breathing manoeuvres (tidal volume, slow maximum and vital capacity expiration, breath holding, and hyperventilation). Estimation of the end expiratory alcohol concentration with the use of simultaneously measured carbon dioxide was shown to reverse the tendency of underestimation at shallow expiration and hyperventilation. These findings indicate that breath alcohol estimations can be performed at shorter expiration time and reduced expired volume compared to existing alcolocks. This is believed to improve their usability and to prevent a possible route for manipulation.

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Alcolocks and alcohol screening devices are becoming commonplace, and their use is expected to grow rapidly with cost reduction and improved usability. A new breath analyzer prototype is demonstrated, with the prospects of eliminating the mouthpiece, reducing expiration time and volume, improving long-term stability, and reducing life cycle cost. Simultaneous CO measurements compensate for the sample dilution and unsaturated expiration. Infrared transmission spectroscopy is used for both the alcohol and CO measurement, yet the entire system is contained within a small handheld unit. Experimental results are reported on the device sensitivity, linearity, resolution, and influence from varying measuring distance. The correlation between early and full-time sampling was established in 60 subjects. Basic concept verification was obtained, whereas resolution and selectivity still needs to be improved. Further improvements are expected by system optimization and integration.