The Anatomy of a DUI – Effects of Alcohol

In my last article I discussed the dose-response relationship of alcohol. But before I move the discussion to the mechanics of an actual DUI arrest, I believe it is important to give readers an understanding of the effects of alcohol from a clinical perspective. As you’ll see, throughout the various stages of intoxication discussed below, overlap in the blood alcohol concentration (BAC) levels will occur because alcohol does not affect every person the same at any given point.  The blood alcohol concentration (BAC) percentages shown below are based on grams of alcohol in every 100 milliliters of blood.

 BAC Levels/Effects

From 0.01% - 0.05%, a person is considered to be in the “subclinical” stage. In this stage a person’s behavior is nearly normal by ordinary observation; a drink or two for most people.

From 0.03% - 0.12%, this stage is considered the “euphoric” stage, with a person’s symptoms being that of mild euphoria, increased sociability, talkativeness, increased self-confidence, and decreased inhibitions. Symptoms also include diminution of attention, judgment and control, which can affect safe driving. This stage is also the beginning of sensory-motor impairment and the loss of efficiency in finer muscle performance tests, which can also affect safe driving. I am certain that we have all experienced persons in this stage. In fact, it is likely that many of us can attest to being in this stage!

From 0.09% - 0.25%, a person is considered to be in the “excitement” stage. Symptoms in this stage include emotional instability and loss of critical judgment. Also, impairment of perception, memory and comprehension can also result at these BAC levels. A decrease in sensatory response, reaction time, reduced visual acuity, peripheral vision and glare recovery also occur. In this stage, a person can also experience sensory-motor incoordination, impaired balance and drowsiness. All of the foregoing symptoms can affect a person’s ability to drive a car safely. This stage is where an individual would be considered “drunk.”

From 0.18% - 0.30%, referred to as the “confusion” stage, a person’s symptoms include disorientation and mental confusion; he/she can experience dizziness as well as exaggerated emotional states. In this stage a person’s vision, perception of color, perception of form, perception of motion and perception of dimensions becomes impaired. Symptoms also include an increased pain threshold as well as increased muscular incoordination, which includes staggering gait, slurred speech, and lethargy. Apathy is also a present in this stage.  Can you say “really drunk” or perhaps “trashed”? And yes, the foregoing symptoms make a person unsafe to drive a car.

From 0.25% - 0.40%, a person is said to be in the stage of “stupor.” In this stage, symptoms include a loss of motor functions and a markedly decreased response to stimuli. In addition, muscular incoordination including the inability to stand or walk also occurs. Vomiting, incontinence, impaired consciousness, sleep or stupor can also result. At these BAC levels the term “wasted” comes to mind. And yes, a person is not safe to drive a car with these conditions.

From 0.35% - 0.50%, a person is considered to be in the “coma” stage, wherein he/she is completely unconscious. The person experiences depressed or abolished reflexes, subnormal body temperature, incontinence, and impairment of the circulation and respiratory systems. Death can result at this stage.

From 0.45% and above, death is likely from respiratory arrest.

 What many people don’t realize is that one’s BAC level continues to climb even after we stop drinking. Consider our hypothetical friend Jack, who starts the evening off with 2 or 3 beers, then he adds 3 or 4 more cocktails, and perhaps 4 or 5 of his favorite shots along the way. As Jack’s BAC rises, he will pass through each of the stages of intoxication discussed above until his BAC peaks, meaning all of the alcohol he drank has been absorbed into his blood stream and his BAC has reached the highest level. In reality, while a person continues to absorb alcohol that is in the stomach, alcohol that is already in the blood stream is beginning to burn off (elimination).

The danger is, because of Jack’s impaired judgment (that can begin as early as the “euphoric” stage) Jack may not make the best decisions and may jeopardize his own safety or someone else’s.   Perhaps Jack gets home after the bar closes and decides to go for a swim to cool off. If Jack’s level of intoxication reaches the “confusion” stage while in the swimming pool, he could very easily drown.

Remember, once the alcohol is in your stomach, it will continue to absorb into your blood stream causing your BAC level to continue to climb. It is not until after your BAC level has peaked, that it will start to decrease. Note that if a person throws-up the contents of the stomach (regurgitate, barf, etc.) then what ever alcohol was in the stomach at the time will not be absorbed.