Gastric Bypass Issues with a DWI

The law in Texas on DWI regarding alcohol is:

  1. Are you normal mentally?
  2. Are you normal physically?
  3. Are you .08 or more at the time of operating a motor vehicle?

The problem with folks who have been arrested for DWI and have had gastric bypass, is that their alcohol metabolism does not reflect a normal person’s alcohol metabolism. When the legislature determined that .08 grams of ethanol in 210 liters of breath, or .08 grams of ethanol in 100 milliliters of blood, at the time of operation is illegal, this was a purposeful, calculated amount of alcohol determined to be the chosen forbidden amount at the time of operation.  The problem with gastric bypass DWIs is twofold:

  1. gastric bypass patients take longer to clear the alcohol from their system (not to peak, there is a difference) and
  2. the amount that is represented in their blood is not proportional to the amount consumed.

The legislature never intended to convict a person on one standard sized drink. Yet, due to altered physiological metabolism in a gastric bypass person, one standard size drink (e.g. 3-5 ounces of wine) will measure over .08 (the legal limit), even though the expected range is near .02 (as reported by the American College of Surgeons in a press release on March 10, 2011 based on a 2007 study[i]).

Numerous studies exist which prove these two serious issues. Just to name a few, a 2002 study in the British Journal of Clinical Pharmacology showed gastric bypass patients peaking in 10 minutes. This is because alcohol absorption is primarily a byproduct of the rate of alcohol that empties into the intestines from the stomach. In gastric bypass people, the stomach is drastically reduced so there is not the same, normal period of stomach passage which can last typically up to 3 hours. The time it takes to metabolize one standard size drink can nearly double (from 49 to 88 minutes)[ii].

The danger in a gastric bypass DWI is for a judge, prosecutor or jury to assume that the reported alcohol volume is representative of the actual amount consumed (it is not). Another danger is equating what is reported as the alcohol amount as anything other than a metabolite, because the central nervous system depressant effects are not in line with the metabolism (peaking far earlier but delayed due to its slowed excretion). Many gastric bypass patients develop hypoglycemia while drinking, whose effects mimic those of intoxication. The glycolic balancing of sugars becomes a problem as a result of the altered normal digestion.

The dangers for misconstruing alcohol consumption due to bypass metabolism figures skew a proper analysis of the facts. For gastric bypass patients who opt to blow into breath test machines, there is an added element of concern regarding belching and digestive issues within the 15 minute observation period that may be missed by the breath test operator. A breath test result contaminated by mouth alcohol residue is meaningless in construing an ethanol value. There is no amount, across the board deduction, or formula that can be used to arrive at a fair estimated alcohol value, either the result is an uncontaminated one or not.

Great care must be taken when it comes to analyzing a DWI case of a gastric bypass defendant. The defense of involuntary intoxication also exists for those defendants who had surgery before the warnings about alcohol use (assuming they did not otherwise become aware). The bottom line is that a gastric bypass DWI cannot be scientifically evaluated in the same traditional manner when it comes to the forensics.


[i] Surgery for Obesity and Related Diseases (2007): 543-548.

[ii] Ibid

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