GERD and breath alcohol testing

The National Highway Traffic Safety Administration (NHTSA) recently published its newest taxpayer publication related to DUI prosecution entitled: Challenges and Defenses II. These publications have generally been a hoot to read.

There is a discussion in that publication on what it terms “The Gastroesophageal reflux disease (GERD) defense.” In reality, it is not a defense, but a physiological and instrumental limitation of the BrAC device to provide for a true measurement that is due exclusively from breath from the lungs (and the oral cavity) as opposed to a combination of undigested headspace gas in the stomach combined with the designed breath path.

Considering I have both published on GERD and BrAC as well as presented at the American Academy of Forensic Sciences, this drew my attention.

I commend NHTSA for at least recognizing that GERD may overstate a BrAC result. I also want to commend NHTSA for the following recommendation, which I have been advocating for years:

The investigating officer can… ask[] two simple questions during their investigation: (1) “Do you have acid reflux?” and (2) “Is it bothering you now?” If the suspect indicates they suffer from GERD, then additional insight can be gained by asking whether they take medication for the condition, how long they have had GERD, and how persistent it is. After the observation period the officer should ask, “Did you have any episodes of acid reflux while you were sitting here?”

However, that type of questioning will not solve the issue and flag those who are inappropriate for BrAC device use. It will help, but not catch everyone that we are concerned with. For example, if a person is taking a GERD related medicine, the medicine does not repair the issue, or stop the results of GERD with the commingling of lung and stomach contents, but it will mask the discomfort. So asking people to simply self diagnose will not work as NHTSA suggests. It would be better that those two questions are asked but also to ask them if they are diagnosed with GERD or a hiatal hernia or any dysfunction of the Lower Esophageal Sphincter. That would be best.

In consultation with my co-authors, collectively we really scratch our heads with this statement:

The defendant would have to be suffering an active bout of GERD immediately prior to the breath test for mouth alcohol to be a viable issue. This active bout requires actual material containing alcohol to be brought up from the stomach into the mouth cavity. Alcohol liquid regurgitated into the esophagus is not enough – it must reach the mouth cavity.

We did note that there is no footnote to support this statement. We know of no support for this limitation as NHTSA presents it.

Finally, the following passage is just false:

Prosecutors should educate the fact finder of the impossibility to belch up stomach contents during a continuous exhalation of breath. An expert witness may or may not be necessary to introduce this evidence. The witness should be prepared to testify that the human body has a small flap of cartilage called the epiglottis that acts as a lid to keep solid food and liquid out of the respiratory tract. The throat contains both an air passage (the wind pipe) and a food passage (the esophagus) and if these passages were both open, air could enter the stomach and food could enter the lungs. The epiglottis actually closes over the esophagus when a person blows into the breath instrument, which would block stomach acid from being released into the mouth.

From my co-presenter and co-author, Dr. Wanda (Marley) Guidry, PhD, MS, CRNA, RN of Rocky Mtn. Medical Legal Consultation, Inc. (re-printed with her permission here)

The epiglottis is a cartilaginous structure that actually moves vertically and also horizontally…much like a toilet seat that goes up and also closes (horizontally).  It ONLY covers the trachea in order to protect it from food, liquids, bugs, etc.  It normally stands up at the top of the voice-box (larynx) to allow air to flow in and out of the wind-pipe (trachea).  However, when we swallow, the hyoid bone elevates and causes the epiglottis to fold over the larynx and trachea to protect it against aspiration (entrance of unwanted stuff that can go down into the lungs).

Even in epiglottitis (inflammation of the epiglottis; which can be deadly), it only covers the larynx & trachea. The danger lies in the fact that the massive swelling can make it very tough to inhale & exhale enough air.

Bottom line: the epiglottis does not block food from arising from the stomach.

Her opinion as to the function and use of the epiglottis is supported by the peer reviewed article “Epiglottic Movement During Breathing in Humans” in the Journal of Physiology, October, 1998.

The common sense analogy is provided by Dr. Michael Hlastala, PhD when he observed “If your sewer backs up, a closed toilet seat and lid will not prevent the overflow!”