For the Defense - Volume 1, Issue 3 - 2016 - 50

In a 2009 case, People v. McNeal,28 the Supreme Court of California reviewed the admissibility of evidence about partition ratio variability to defend against a generic DUI charge. In that state, breath-testing machines incorporate a partition ratio of 2100:1. The Supreme Court stated: "Machines in California use a conversion factor of 2,100 to 1, meaning "the amount of alcohol in 2,100 milliliters of alveolar breath is equivalent to the amount of alcohol in 1 milliliter of blood." The Court, also stated: "This ratio is used, apparently without exception, in breath-testing devices throughout the United States." Additionally, the Supreme Court stated: "Nevertheless, courts here and across the country have long recognized that actual partition ratios vary, both among members of the population and within a single individual." The Supreme Court made the clear statement: "We reach the same conclusion as the Vermont and Arizona courts. If the defendant in a section 23152(a) case offers competent evidence showing that the use of a 2,100-to-1 conversion ratio may have yielded an inaccurate representation of his blood-alcohol level, introduction of the evidence is permissible. Examples of Variable Partition Ratios for Individuals 1756:1 (not 2100:1) at 37 Centigrade (normal body temperature).30 This difference causes a 20% discrepancy between the directly measured value of 1756:1 and the machine blood/breath ratio 2100:1 (2100/1756 = 1.2). This is explained by the loss of alcohol to the lung airway mucosa.31 Because of the wide variances in human blood to breath partition ratios, what do you think about the accuracy of a breath result? As an example, if your client has a partition ratio of 1050:1, what is their breath result compared to a simultaneous blood alcohol result? If the blood result is 0.10, the breath result would be 0.20. This is because the machine fixed value of 2100:1 is twice the value of 1050:1 for your client. This is a vast difference. Notes 1. 2. 3. 4. 5. 6. Hypothetical A: 7. If in the U.K. and Holland (2300:1), an individual's breath test result is 0.1, the 0.1 value in the U.S. (2100:1) would be (0.1) divided by 2100 times the U.K. value, 2300, to give a result of 0.109 on a U.S. (2100:1) machine. Hypothetical B: If in Austria and France (2000:1), an individual breath test result is 0.1, the 0.1 value in the U.S. (2100:1) would be 0.1 divided by 2100 times the Austrian value 2000, to give a result of 0.095 Interestingly, the partition coefficients for water/air, whole blood/air and plasma/air are 2133, 1756 and 2022, respectively.29 Thus, the alveolar air alcohol concentration when compared to the blood alcohol concentration (BAC) has a ratio of 50 For The Defense | Vol. 1, Issue 3 8. 9. 10. 11. 12. Castellan, G.W., Physical Chemistry. Reading, MA: Addison-Wesley (1966). Henry, W., Experiments on the Quantity of Gases Absorbed by Water at Different Temperatures and Different Pressures. Phil. Trans. Roy. Soc. 1803; 93:29-42. Workman, J., Springsteen, A., Applied Spectroscopy. Chestnut Hill, MA: Academic Press (1998). Hlastala, M.P., Paradigm Shift for the Alcohol Breath Test. J. Forensic. Sci. 2010; 451-456. Id. Hlastala, M.P., Anderson J.C., The Impact of Breathing Pattern and Lung Size on the Alcohol Breath Test. Ann. Biomed. Eng. 2007; 35:264-272. Jones, A.W., Maerdh, G. Anygaerd, E., Determination of Endogenous Ethanol in Blood, and Breath by Gas Chromatography-Mass Spectrometry. Pharm. Biochem. and Behavior. 1983; 18(1):267-272. Jones, A.W., Quantitative Measurements of the Alcohol Concentration and the Temperature of Breath During a Prolonged Exhalation. Acta. Physiol. Scand. 1982; 114:407-412. Tsu, M.E., Babb, A.L., Ralph, D.D., Hlastala, M.P., Dynamics of Heat, Water and Soluble Gas Exchange in Human Airways: I. A Model Study. Ann. Biomed. Eng. 1988; 16:547-571. Ohlsson, J., Ralph, D.D., Mandelhorn, M.A., Babb, A.L., Hlastala, M.P., Accurate Measurement of Blood Alcohol Concentration with Isothermal Rebreathing, J. Stud. Alc. 1990; 51:6-13. Fowler, W.S., Lung Function Studies, II. The Respiratory Dead Space. Am. J. Physiol. 1948; 154:405-416. Rahn, H., Mohoney, J., Otis, A.B., Fenn, W.O. A

Table of Contents for the Digital Edition of For the Defense - Volume 1, Issue 3 - 2016