Suspected drunk drivers could soon be told by police to put on a pair of earmuffs, if a new device comes to fruition.
Japanese scientists have developed a pair of earmuffs that can estimate blood alcohol levels based on ‘transcutaneous gas’ – gas released through the skin.
The earmuffs, presented as a proof-of-concept in a new study, detect ethanol compounds in transcutaneous gas released by the ears.
In trials, the device measured alcohol intake as well as a traditional breathalyzer, although the process took much longer — more than two hours, compared to what can be just a few minutes for breath testers when stopped by the roadside.
A schematic of the ear-derived ethanol monitoring system consisting of earmuffs and an ethanol vapor sensor (bio-sniffer)
But a breathalyzer is usually much more invasive, often requiring a tube to be inserted into the mouth.
Also, products such as mouthwash or breath spray can “fool” some breath testers by significantly increasing test results. Listerine mouthwash, for example, contains 27 percent alcohol.
It also measures other chemical compounds – acetone (a marker of lipid metabolism) and acetaldehyde (a known cancer-causing detection in the body after drinking).
The device was developed by a Japanese team led by Kohji Mitsubayashi of Tokyo Medical and Dental University.
“We explored the possibility of external ears for stable and real-time measurement of ethanol vapor,” they say in their study.
‘For stable monitoring of transcutaneous gas, it is essential to find a body part with little interference with the measurement.
“Transcutaneous gas is more suitable for real-time and continuous assessment than breath.”
Chemical compounds released through the skin mirror the chemical compounds present in the blood circulating in the body, including that of alcohol (ethanol).
Admittedly, breath and ‘transcutaneous gas’ measurements are not as accurate a measure of blood alcohol levels as blood and urine samples (although these are much more invasive).
ALCOHOL AND RESPIRATORY PRODUCTS
Alcohol, also known as ethanol, is the main component of alcoholic beverages such as beer, wine and spirits.
When you drink an alcoholic beverage, it is absorbed into your bloodstream and processed by the liver.
As the alcohol in the blood travels to the lungs, some of it will evaporate into the air in the small lung sacs known as alveoli, and be exhaled from the body (“alcohol breathing”).
It is this alcohol that a breathalyzer is designed to measure. Therefore, when using a breath analyzer, it is necessary to measure deep lung air.
Although a breathalyzer gives quick results, it is not as accurate as measuring alcohol in the blood.
So no breath test is as accurate as a blood or urine test.
The team’s device consists of a modified pair of commercial earmuffs that capture gas released through the skin of a person’s ears, and an ethanol vapor sensor.
When the sensor detects ethanol vapor in the gas, it emits light with different intensities depending on the ethanol concentrations detected.
In experiments, the authors used their device to continuously monitor the ethanol vapor released by the ears of three male volunteers.
First, the base ethanol concentrations of the transcutaneous ear gas were measured for 10 minutes without drinking alcohol.
The volunteers then drank alcohol in the concentration of 0.4 g per kg body weight within five minutes, and the measurement continued for another 140 minutes.
The breath ethanol concentrations of the volunteers were also measured at regular intervals using an additional ethanol vapor sensor and a device with reagents that change color when exposed to ethanol.
The authors noted that changes in the concentration of ethanol released by the ears and breath over time were similar for all volunteers.
Previous research has found that breath and blood ethanol concentrations are correlated, indicating that the device can be used in place of a breath analyzer to estimate blood alcohol levels.
The results of the earmuffs were similar to a breath test, but a breath analysis test is much more invasive and requires a tube to be inserted into the mouth. Pictured, an Australian officer using a breath analyzer on the driver. Products such as mouthwash or breath spray can ‘fool’ some breath analyzers by significantly increasing test results. Listerine mouthwash, for example, contains 27 percent alcohol.
The average highest concentration of ethanol released through the ears was found to be 148 parts per billion.
Previous devices used the hand to measure blood alcohol levels as a less invasive alternative to putting a tube in someone’s mouth.
But 148 parts per billion is double the concentration previously reported from the skin of the hand, the researchers say, suggesting the ears are more suitable.
Sweat from sweat glands in the hand can also interfere with the measurements, the researchers point out. In comparison, an external ear canal does not have an eccrine sweat gland.
“Each body part has a different density of sweat glands and epidermis layers of the skin,” they say. “That’s why it’s important to choose a good body region.”
The authors also propose that the device could be used to measure other gases released through the skin, for example in disease screening.
The study is published in Scientific Reports.
DO YOU DRINK TOO MUCH ALCOHOL? THE 10 QUESTIONS THAT REVEAL YOUR RISK
A screening tool commonly used by medical professionals is the AUDIT (Alcohol Use Disorders Identification Tests). The 10-question test was developed in collaboration with the World Health Organization and is considered the gold standard for determining whether someone has problems with alcohol abuse.
The test is reproduced here with permission from the WHO.
To complete it, answer each question and write down the corresponding score.
0-7: You are within the responsible drinking range and have a low risk of alcohol-related problems.
More than 8: Mention harmful or dangerous drinking.
8-15: Average risk level. If you drink at your current level, you risk developing problems with your health and your life in general, such as work and relationships. Consider decreasing (see below for tips).
16-19: Higher risk of complications from alcohol. Cutting back on your own can be difficult at this level, as you may be dependent, so you may need professional help from your GP and/or a counselor.
20 years and older: Possible dependence. Your alcohol use is already causing problems and you could very well be dependent. You should definitely consider stopping gradually or at least reducing your drinking. You should seek professional help to determine your dependence and the safest way to quit alcohol.
Severe dependence may require medically assisted withdrawal or detox in a hospital or specialist clinic. This is due to the potential for severe alcohol withdrawal symptoms in the first 48 hours requiring specialist treatment.