| Want to trick a breath machine into a low test result? | | | | the Law 275.) |
| Or make sure that you're not causing a false high | | | | Dr. Michael Hlastala, Professor of Physiology, |
| reading? Not that difficult, says a law firm of San | | | | Biophysics and Medicine at the University of |
| Diego DUI attorneys and lawyers: just control your | | | | Washington has gone farther and concluded: |
| breathing. | | | | "By far, the most overlooked error in breath testing for |
| The simple fact is that these breath machines which | | | | alcohol is the pattern of breathing... The concentration |
| determine guilt or innocence in DUI cases are not | | | | of alcohol changes considerably during the breath... The |
| exactly the reliable devices that law enforcement | | | | first part of the breath, after discarding the dead |
| would have us believe. There are dozens of factors | | | | space, has an alcohol concentration much lower than |
| that can cause false test results. An example of that | | | | the equivalent BAC (blood-alcohol concentration). |
| unreliability is the fact that the results will vary | | | | Whereas, the last part of the breath has an alcohol |
| depending upon the breathing pattern of the person | | | | concentration that is much higher than the equivalent |
| being tested. This has been confirmed in a number of | | | | BAC. The last part of the breath can be over 50% |
| scientific studies. | | | | above the alcohol level... Thus, a breath tester reading |
| In one, for example, a group of men drank moderate | | | | of 0.14% taken from the last part of the breath may |
| doses of alcohol and their blood-alcohol levels were | | | | indicate that the blood level is only 0.09%." 9(6) The |
| then measured by gas chromatographic analysis of | | | | Champion 16 (1985). |
| their breath. The breathing techniques were then | | | | Many police officers know this. They also know that if |
| varied. The results indicated that holding your breath | | | | the machine contradicts their judgement that the |
| for 30 seconds before exhaling increased the | | | | person they arrested is intoxicated, they won't look |
| blood-alcohol level by 15.7%. Hyperventilating for 20 | | | | good. So when they tell the arrestee to blow into the |
| seconds immediately before the analyses of breath, | | | | machine's mouthpiece, they'll yell at him, "Keep |
| on the other hand, decreased the level by 10.6%. | | | | breathing! Breathe harder! Harder!" As Professor |
| Keeping the mouth closed for five minutes and using | | | | Hlastala has found, this ensures that the breath |
| shallow nasal breathing resulted in increasing the | | | | captured by the machine will be from the bottom of |
| blood-alcohol level by 7.3%, and testing after a slow, | | | | the lungs, near the alveolar sacs, which will be richest in |
| 20-second exhalation increased levels by 2%. ("How | | | | alcohol. With the higher alcohol concentration, the |
| Breathing Techniques Can Influence the Results of | | | | machine will give a higher -- but inaccurate -- reading. |
| Breath-Alcohol Analyses", 22(4) Medical Science and | | | | |