| 1. |
- Kaisdotter Andersson (Jonsson), Annika, et al.
(författare)
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Methodology investigation of expirograms for enabling contact free breath alcohol analysis
- 2009
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 3:3, s. 036002-
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Tidskriftsartikel (refereegranskat)abstract
- The present techniques for breath alcohol determination have usability limitations concerning practical use and the time and effort required for the test person. The rationale of the physiological assumptions in a recently demonstrated technique for breath analysis without a mouthpiece is investigated in this paper. Expirograms quantifying ethanol, carbon dioxide (CO2) and water (H2O) from 30 test subjects were analysed, with respect to the influence of individual variations in end-expiratory CO2 and H2O concentrations, and possible benefits from simultaneous measurement of CO2 or H2O. Both healthy subjects and patients suffering from pulmonary diseases performed breath tests with small and maximum volume expiration. The breath tests were recorded basically with a standard evidential instrument using infrared absorption spectroscopy, and equipped with a mouthpiece. Average concentrations were significantly higher for the maximum than for the small expirations. For the maximum expirations, the healthy subjects had a significantly higher end-expired PCO2 of 4.4 ± 0.5 kPa (mean ± standard deviation) than the patients (3.9 ± 0.7 kPa). The corresponding values for H2O were 39 ± 1 and 38 ± 1 mg l−1. The results indicate that the CO2 variability is consistent with the requirements of accuracy for alcohol ignition interlocks. In addition, CO2 as tracer gas is preferable to H2O due to its low concentration in ambient air. In instruments for evidential purposes H2O may be required as tracer gas for increased accuracy. Furthermore, the study provides support for early determination of breath alcohol concentration, indicating that determination after 2 s will introduce an additional random error of 0.02 mg l−1 or less.
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| 2. |
- Hagblad, Jimmie, et al.
(författare)
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A technique based on laser Doppler flowmetry and photoplethysmography for simultaneously monitoring blood flow at different tissue depths
- 2010
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Ingår i: Medical and Biological Engineering and Computing. - : Springer Science Business Media. - 0140-0118 .- 1741-0444. ; 48:5, s. 415-422
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to validate a non-invasive optical probe for simultaneous blood flow measurement at different vascular depths combining three photoplethysmography (PPG) channels and laser Doppler flowmeter (LDF). Wavelengths of the PPG were near-infrared 810 nm with source-to-detector separation of 10 and 25 mm, and green 560 nm with source-to-detector separation of 4 mm. The probe is intended for clinical studies of pressure ulcer aetiology. The probe was placed over the trapezius muscle, and depths from the skin to the trapezius muscle were measured using ultrasound and varied between 3.8 and 23 mm in the 11 subjects included. A provocation procedure inducing a local enhancement of blood flow in the trapezius muscle was used. Blood flows at rest and post-exercise were compared. It can be concluded that this probe is useful as a tool for discriminating between blood flows at different vascular tissue depths. The vascular depths reached for the different channels in this study were at least 23 mm for the near-infrared PPG channel (source-to-detector separation 25 mm), 10-15 mm for the near-infrared PPG channel (separation 10 mm), and shallower than 4 mm for both the green PPG channel (separation 4 mm) and LDF.
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| 3. |
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| 4. |
- Hök, Bertil, et al.
(författare)
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Unobtrusive and Highly Accurate Breath Alcohol Analysis Enabled by Improved Methodology and Technology
- 2014
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Ingår i: Journal of Forensic Investigation. - : Avens Publishing Group. - 2330-0396. ; 2:4, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
- Kaisdotter Andersson (Jonsson), Annika, et al.
(författare)
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Development of a breath alcohol analyzer for use on patients in emergency care
- 2009
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Ingår i: IFMBE Proceedings, vol. 25, no. 1. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783642038907 ; , s. 84-87
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Konferensbidrag (refereegranskat)abstract
- The quantification of breath alcohol concentration is considered important input in medical diagnosis and triage at emergency medical care. In many severe emergency cases, for example head injuries, stroke, heart attack, diabetes, or psychological illness, the medical condition of the patient can be mistaken for alcohol intoxication. In cases like these, quantification of the alcohol concentration would facilitate and speed up the diagnostic procedure. However, the use of breath analyzers in medical care is limited as the state-of-the-art devices require active involvement of the patient, and expiratory volume and flow incompatible with patients respiratory function. This paper presents a prototype of a handheld breath analyzer based on infrared spectroscopy which does not require active involvement from the patient and also provides direct feedback on the quality of the breath test by measurement of the expired PCO2.
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