A commonly held belief since the 1950’s upon which breath alcohol testing has rested since the 1950’s that breath test devices measure “deep lung” or alveolar air. This belief has been refuted multiple times by research over the last 20 years and has given us all a greater knowledge of the exchange of highly soluble gases in the lungs. Because of this research, we can no longer assume alveolar air is the same as blood alcohol content and the breath test reading reaches an area of stability.

Research conducted by Dr. Michael Hlastala of the University of Washington has found that when inhaling, the cooler and dryer air being inhaled becomes warmer and absorbs liquid into the airways. This air also absorbs soluble gases that are dissolved in the lungs. When exhaling, the air is cooled and dehumified, and the alcohol present in a breath sample comes entirely from the lining of the airways. This mucus and tissue, not the blood in the lower part of the lungs, is the source of “breath alcohol concentrations” (BrAC).

Additional research by Hlastala has found the BrAC continues to go up as a person exhales until they run out of breath. This causes the flattening, or stabilization, of the BrAC. It has also been found the average directly measured partition coefficient for alcohol in blood at 98.6 degrees Fahrenheit is 1756:1, not 2100:1, as is assumed by the Intoxilyzer 5000 device used in Georgia. Also discovered is blowing a volume beyond the minimum required for a breath testing device results in an increased breath alcohol reading and a lower blood-to-breath partition ratio. This creates an unfair advantage for those with a larger lung capacity because they can blow more air into a device to get a printed result than those with a smaller lung capacity.

According to Dr. Hlastala, alcohol reaches the surface of airways by diffusing from the bronchial circulation. When a person inhales, alcohol is taken from the airway surface and the inhaled breath becomes inundated with alcohol as it reaches the alveoli, where “deep lung air” is found. In the alveoli, alcohol in the breath is in balance with alcohol in the pulmonary capillary blood. Even though ethyl alcohol may exchange with the blood in the alveoli, since there is no partial pressure difference, there is no net change. The exchange in the airways will happen even though the bronchial blood flow is only about one percent of the total cardiac output because of alcohol’s extremely high solubility.

When a person exhales, Hlastala found the alcohol in the air passing from the alveoli to the mouth leaves alcohol on the surface of the airways. In the meantime, some alcohol has re-entered the blood stream by way of the bronchial circulation. So the airways have been partially recharged with alcohol.
But there is still a net partial pressure driving force toward the airway tissue, Hlastala discovered. With an average exhalation, the exhaled air loses about 20 percent of the alcohol that it had in the alveoli. If a person takes a full and complete inhalation and exhalation, they would lose less alcohol and the measured alcohol in the breath would be higher than it should be. If a short exhalation occurs, then the alcohol measured in the breath will be lower than expected.

Both Georgia and Florida buy their official state administered breath test machines from CMI, Inc. of Owensboro, Ky. A recent review of the “pressure transducer” of 231 of Florida’s Intoxilyzer 8000s has revealed that 40 percent of them record the wrong breath volume. Breath volume is a critical factor in determining blood alcohol content based on breath. The legal limit in Georgia is 0.08 grams of alcohol in 2.1 liters of air. About 1.1 liters of air exist in the mouth and throat, but it is the crucial last liter that contains the deep lung air where alcohol concentrations can be used to determine blood alcohol estimates. Too little air and too much air can both misjudge blood alcohol content. It has long been argued that a person over blowing in a device can overstate the blood alcohol reading. This irregularity was revealed in Florida when a 170 pound man purportedly blew 12 liters of air from his lungs into a device, which is physically impossible. Further review found the faulty “pressure transducer” was not regularly calibrated or checked by State breath testing agencies in either Florida or Georgia. These same problems could not be discovered in Georgia because the state has had the Intoxilyzer computer code altered so it does not report breath volume. This is on top of the discovery that the Intoxilyzer 8000, which performs the calibration check between every test, that Georgia performs once a quarter on an early version, the Intoxilyzer 5000, was producing on average of 80 failures a month per machine.

Breath testing science is far too susceptible to equipment error to be the sole foundation of a criminal conviction, jail time and collateral consequences like the destruction of careers, Hlastala concluded. This is even more critical when someone is accused of only blowing slightly over the legal limit of .08.

This research shows anyone who has been arrested based on BrAC tests needs to discuss their case with an experienced attorney. If you have been charged with DUI in the south Georgia area, call me today to discuss your case and possible defenses. I will be happy to speak to you about the facts of your particular case and how to navigate through the court system.

Dove Law Firm, LLC, is located in Ocilla and serves residents throughout South Georgia. From the beginning to the end, we deliver excellent legal services for residents of Ocilla, Fitzgerald, Tifton, Douglas, Moultrie, Hazlehurst, Abbeville, Nashville, Adel, Cordele, McRae, Sylvester and Ashburn. – See more at: http://dovelawllc.com/news/dui-problems-with-the-breath-test/#sthash.dy8OuZKm.dpuf