Sunday, September 30, 2007

Dr. Hlastala's breath test case analysis

California DUI / drunk driving criminal defense info

September Term 2005

Docket No. 58,879



















On remand from the Supreme Court of New Jersey: December 14, 2005

Findings and Conclusions Submitted to Supreme Court: February 13, 2007

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[Page 213]

13. Summary of Testimony of Defendants' Expert, Michael Hlastala

Michael Hlastala is a professor at the University of Washington where he holds appointments in the Department of Medicine (Division of Pulmonary and Critical Care) and the Department of Physiology and Biophysics (65T4-65T5). He also is an adjunct professor of bioengineering (65T5). He has a doctoral degree in physiology from the State University of New York at Buffalo (65T5;65T12).

As his extensive curriculum vitae shows, Hlastala is a member of several professional organizations and has received a number of awards including a John Simon Guggenheim Foundation Fellowship and an honorary medical degree from the University of Linkoping in Sweden (65T7). He has given lectures at universities both within and outside of the United States, and has written numerous articles on physiology including several on breath testing, as well as one book on respiratory physiology (65T7-65T9;65T14;65T17-65T18).

Hlastala's primary field of study deals with gas exchange physiology, especially the way in which highly soluble gases, such as alcohol, exchange in the lungs (65T9-65T10). In his laboratory, Hlastala has used a Breathalyzer 900A, Datamaster, and Intoxilyzer 5000, but not an Alcotest 7110 (65T12-65T13). He also has experience with pulmonary function testing as well [Page 214] as gas chromatography and mass spectrometry with respect to the measurement of alcohol and other substances (65T11-65T12).

Hlastala has served as an expert witness in more than 1400 cases, including Downie (65T5-65T6;65T9-65T10). Defendants offered him as an expert in physiology as it relates to breath testing (65T10). Hlastala offered testimony in three areas: (1) the exchange of alcohol in the lungs; (2) the detection of mouth alcohol; and (3) the presence of interferents (65T26-65T27). Each area is discussed below.

Alcohol Exchange

The old paradigm assumed that the breath sample tested at the end of a full exhalation was the equivalent of alveolar air in equilibrium with the blood (65T29). Hlastala disagreed, stating that the end-exhaled breath was not the same as deep lung air because of the exchange of alcohol in the airways (65T29).

Briefly, the respiratory system consists of airways which travel from the nasal cavity down the throat to the trachea, then split into two branches just above the heart, and continue to branch or split more than twenty times until they fill the chest cavity (65T31;D-172). The airways are lined with mucus, and gradually get smaller in size causing air movement to slow down (65T31-65T32). At the end of the airways, there are alveoli or air sacs surrounded by blood vessels where gas [Page 215] exchange takes place, meaning oxygen enters the blood and carbon dioxide leaves it (65T31-65T32;D-172).

Because alcohol is highly soluble, it adheres to the water-laden mucus on the surface of the airways (65T32). During inhalation, breath air picks up alcohol from the airway surfaces which increases the alcohol concentration to the point of saturation by the time the air reaches the alveoli (65T32-65T34;65T36).

During exhalation, however, the alcohol concentration decreases as the alcohol interacts with the airway tissue on its way to the mouth (65T34-65T38;65T43-65T46;66T5). The amount of interaction varies among individuals based upon certain physiological factors such as breathing patterns (65T34-65T35;65T44-65T45). Citing studies by A.W. Jones and others, Hlastala noted that subjects who held their breath or blew longer caused a warming of the airway tissues which resulted in less alcohol deposited there during exhalation and higher readings (65T40-65T43). Conversely, subjects who hyperventilated before their breath tests would cause additional cooling of the airway surfaces which would result in a greater loss of alcohol during exhalation and lower readings (65T41-65T43).

Another factor is temperature, both body and breath (65T43;65T56-65T57). For example, Hlastala cited a study by Dr. [Page 216] Fox showing that a higher body temperature caused higher breath test values and vice versa (65T55). To compensate for the higher alcohol readings, Dr. Fox apparently found that there should be an adjustment of 8% for every degree that body temperature rose above normal (65T55-65T56).1 Hlastala also relied upon other researchers who reported breath temperature changes could cause alcohol readings to vary by 6.5% (65T69). Hlastala, however, did not recommend correcting for breath or body temperature without more experiments (65T69-65T70).

A third factor was hematocrit, which Hlastala described as the relationship between red cells and plasma (a watery substance) in the blood (65T57). According to Hlastala, females had a slightly lower hematocrit resulting in lower breath test values as more alcohol was retained in the plasma (65T57-65T58). Hlastala, however, acknowledged that there were no studies showing hematocrit differences relating to variations in breath alcohol concentrations (66T40).

Relying upon experimental work performed by other researchers, Hlastala also found that people with smaller lung volumes had higher readings and concluded that breath testing discriminated against them (65T62-65T67;66T14-66T15;66T40;D-[Page 217]256;D-261). He recommended more tests to understand the difference and correct for it (65T67).

Hlastala agreed that the 2100:1 blood-breath ratio used in the Alcotest 7110 tended to underestimate blood alcohol (66T37). While recognizing that the ratio varied among populations, he used Jones' finding that the actual ratio of blood and air in a closed container was approximately 1756:1 to conclude find that, on average, exhaled breath lost 20% of the alcohol to the mucosal surface of the airways (65T75-65T77;D-265).

To compensate for the physiological variables under the "new paradigm," Hlastala suggested using a blood-breath ratio of 1750:1 (66T6-66T9). While a 1750:1 ratio would favor more defendants, Hlastala pointed out that it would favor some (such as those with higher lung volume, lower temperature or lower hematocrit) more than others (65T83).

Hlastala also took issue with the breath-testing concept that a subject had reached alveolar air expulsion when the breath leveled off or reached a plateau (66T63-66T64). Instead, he claimed that a breath-testing instrument actually was measuring the level at which the subject stopped exhaling (66T64). He also did not see a need for truncating test results and recommended taking the average of the four readings, not the lowest (66T37-66T38).

[Page 218] Because end-expired breath was never the same as deep lung air, Hlastala recommended taking blood samples and if that was not practical, using an isothermal re-breathing device which required a subject to breathe in and out of a heated bag about five or six times (65T50-65T51;65T80). As he explained, the device produced more uniform breath alcohol measurements which better represented blood alcohol (65T50-65T54).2 A single breath exhalation, however, underestimated an isothermal rebreathing sample, requiring a change in the blood-breath ratio from 2100 to about 1950:1 (66T22-66T23;66T25). To date, no state has used an isothermal rebreathing device (66T26).

Hlastala explained that he proposed the new paradigm in response to anomalies in the old one (66T16). He recognized, however, the need for more experiments to confirm the new paradigm or create another (66T16). He explained, "it's new information. It's only a decade or decade-and-a-half old and we need to do those experiments to validate it" (66T17-66T18). He also recommended further experiments on breath temperature before advocating a particular deduction (66T39).

[Page 219] Hlastala was aware that forensic scientists, unlike the medical community, did not accept the new paradigm (66T16;66T63). Because forensic scientists failed to consider the physiological variables, Hlastala observed that all breath-testing programs had similar biases (66T16).

Mouth Alcohol

Hlastala recognized that the presence of mouth alcohol can result in false higher breath alcohol readings (65T91). Such elevations can be caused by recent drinking, regurgitation or gastroesophageal reflux disease (GERD), or by the presence of dentures or other materials that absorb alcohol (65T92).

He also recognized that the Alcotest 7110's infrared technology used a slope detector to detect mouth alcohol (65T89). In Hlastala's opinion, however, the slope detector was not "foolproof" because it did not work properly when alcohol was present both in the bloodstream and the mouth (65T85-65T88). In his report, he wrote:

The simple explanation is that the decreasing slope for alcohol coming from the mouth offsets the rising (positive slope) on alcohol exhaled from the lungs. Since a negative slope is not detected, the slope detector will not identify mouth alcohol under this situation. While the slope detector is an important check against mouth alcohol, it does not work well when alcohol is also present in the body.

[C-15, Hlastala report at 3.]

[Page 220] While Hlastala tested the slope detectors on the Datamaster and Intoxilyzer 5000, he never actually tested the slope detector on the Alcotest 7110 (66T46;D-257).

In Hlastala's opinion, the two-minute lockout between breath tests and the twenty-minute observation periods also did not provide complete safeguards against mouth alcohol (65T92-65T93). When asked if the combination of the slope detector, two-minute lockout, and twenty-minute observation period was sufficient, Hlastala responded that they would be helpful but it still would be difficult to detect internal regurgitation or GERD (65T94-65T95). He stated, however, that twenty minutes was a sufficient period of time to wait to stabilize the saliva concentrations if there was any vomiting (65T96).


Relying upon the instructor training manual for the Alcotest 7110, Hlastala noted that it described ethyl alcohol and other alcohols, but did not explain how the instrument differentiated between ethanol and methanol, or any other alcohol especially when there were only trace amounts present (65T98-65T101;D-7). In particular, he expressed concern that there was no data showing the effect of small amounts of other contaminants such as isopropyl alcohol (65T102-65T103).

On cross-examination, Hlastala admitted that he did not know NHTSA had tested a generic Alcotest 7110 and firmware [Page 221] versions 3.8 and 3.11, that he was not familiar with NHTSA's model specifications relating to acetone, that he was unaware of OIML Recommendation 126 (which applied to evidential breath testers), and that he did not review the data from Brettell's study on interferents (66T53-66T55).

Hlastala was aware that the instrument detected interferents by comparing the tests results of the IR and EC methods of analysis (65T104). In his opinion, the real issue was how sensitive those two methods were for making the requisite measurements (65T104). He recommended Draeger perform experiments with different levels of interferents to determine the sensitive activity for minimum amounts (65T104-65T105). If contaminants existed, he recommended that the State consider subtracting .01 from the readings in every case (65T105). In the State of Washington, defense counsel argued for a similar adjustment in cases with close readings (65T105).

In his opinion and to a reasonable degree of certainty within his field, the scientific reliability of the Alcotest 7110 could not be assessed because Draeger failed to measure interferents or define the minimum value for uncertainty with regard to potential contaminants (66T10-66T11). Such information would have enhanced his understanding of the instrument (66T11).

[Page 222] We do not doubt Hlastala's sincerity or his integrity but he concedes that his "new paradigm" for evidential breath testing is in the developmental or experimental phase. We are not persuaded that these theories are correct or sufficiently documented at present. As in Downie, 117 N.J. at 454, Hlastala "outlined potential physical variables that could affect the blood-breath partition ratio." Ibid. We are not convinced by his testimony here to reject the conclusions of Downie and adopt his theory that evidentiary breath testing is currently unreliable.


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[Page 230]

2. The State's proofs on the question of the reliability of the partition or blood-breath ratio largely mirrored the State's presentation in Downie. We do not doubt the integrity and sincerity of any witness in this proceeding, presented either by the State or defense. At most, there were shades of differences about interpretation of scientific data or understandable dispute over au courant scientific theory. We find no reason in the evidence to doubt the continuing validity [Page 231] of the underlying theory of a 2100:1 blood-breath ratio. The testimony of Dr. Hlastala and Dr. Simpson, on the Heifer (Bonn) and other data, presented by the defense is interesting but certainly not convincing. It perhaps may represent the next frontier in the forensic science of evidential breath testing if eventually supported by sufficient proofs ─ but it is not yet vigorous enough, if it ever will be, to up-root the science explicated and found persuasive in Downie and fortified by the extensive proofs before this court. Thus we reject the defense witnesses' basic premise that the 2100:1 ratio and present breath-testing technology is fundamentally unreliable, especially when adopted, as it has been in New Jersey, with caution and appropriate leeway, so as not likely to ensnare the innocent. Of course, here the defendant has the benefit of the lowest of four independent readings (two IR and two IC) derived from two separate breath samples. This is the foremost safeguard.

1 Dr. Fox's study was not marked into evidence.

2 For a more detailed discussion, see J. Ohlson, D.D. Ralph, M.A. Mandelkorn, A.L. Babb, and M.P. Hlastala, Accurate Measurement of Blood Alcohol Concentration with Isothermal Rebreathing, 51 J. of Studies on Alcohol 6 (1990) (S-74). For that study, Hlastala and his co-authors dosed fourteen volunteers with alcohol to examine such breathing parameters as hyperventilation (66T13-66T14;66T23-66T24).