Contido de alcol no sangue (BAC) non invasivo mediante PPG

Sobriety test, which commonly uses a breathalyzer for estimating blood alcohol content (BAC) from a breath sample, is commonly used to detect drunk driving. Although drinking alcohol has long been a common practice in people’s daily life, it may induce negative impacts when consumed in excess. The impact of drinking alcohol depends on how much it was taken and the physical condition of the individual.

Alcohol-impaired driving is a worldwide leading cause of traffic accident injuries and fatalities. In 2014, 9967 people were killed in drunk driving crashes, accounting for nearly 31% of all traffic-related deaths in the USA.

A sobriety test that measures the driver’s blood alcohol concentration (BAC) is commonly adopted to determine whether a driver is dangerous to drive on the road. Two methods can be used: breath test and blood test. The former uses a breathalyzer to measure alcohol concentration in the air generated from the act of exhalation. It is widely accepted because it is non-invasive, portable and able to generate immediate results.

The later directly measures the amount of alcohol in the subject’s blood, which is generally more accurate than the former.  However, it needs to invade human body for sampling. In addition, taking a blood test does have drawbacks on the concerns of hygiene and inconvenience.

It is well known that drinking alcohol makes a change in BAC.  It also affects human’s cardiac activity. Roughly speaking, the more alcohol one takes, the faster the heart beats. We use this to correlate the relationship between BAC and heartbeat.  We analyze the photoplethysmography (PPG) signal, which is a well-known non-invasive technique that detects heart rate, respiration rate, blood pressure, blood oxygen saturation etc. Our research shows solid cues in the PPG single that reveals the level of BAC indirectly.

In fact the accuracy of classification can be obtained up to 87.50%. This suggests that our PPG technique has a potential for screening of BAC.