Sensing Breath and Air
heart rate / cardiovascular
Erica Forzani shares her experience at the Center of Bioelectronics and Biosensors at Arizona State University. She talks about the development of their new gadgets and the challenges they faced.
What we try to do is the development of new gadgets basically chemical sensor devices and we usually find the problem that when you need to sense specific and very selectively molecules that are very low concentrations, it’s literally like trying to find a needle in a haystack.
So it’s a challenge for us as engineers, and the way we came around the problem is by doing devices that integrate not only specific sensors but also the specific sample collectors and conditioners so that we can be sure about the samples that we collect and the specificity and sensitivity of the detection .
So we have also developed a special circuit detection that allowed us to process the signal in the way that we can increase the signals to noise (generation?) so we call this approach integrated approach and we have applied the approach to different conditions.
One condition is to find out what is in the air we breathe. Many times we ride a bike or inside an office for most of the time of the day and there is molecules there that can be toxic to us.
So in order to answer this question we have also found the pollution that we generate have caused over the years quite a damage in the health of people. You can see here in this plot for example the mean ventilation air rate that means the number of maybe liters that we expire have been increasing throughout the years in a century for example.
So that has caused a problem because our brain is basically exposed to less oxygen, and this is a clear response to less oxygen concentration in our brains. The pollution has also created a high incidence of asthma in people living close to highways for example.
So this is a great example to see how a small device could impact people’s life if we have a way to bring it to the public and track the pollution exposure. So if we look for example to our pollution exposure through a general resource like air, where these pollution maps are built on environments and regions you can find that if you zoom into a region like the Phoenix area for specific days the air has a moderate pollution level.
But if you put a personal monitor, monitoring the pollution of a specific person that same day, you can see that the person can be exposed to really high levels that are in the red zone and not in the yellow zone, or for most of the time be in the green zone.
So it is really up to the personal exposure monitoring in what we need to target in order to know what in the air we are breathing can influence our health.
So here is an example where we compare these devices to the GPS of the phone that contains the user interphase, and you can see here the traffic exposure pollution level as a location and of time. You can see the park areas in general are very clean compared to areas near highways where you expect o have much more exposure to pollution.
So this is the device we created, and we can send is total hydrocarbons coming from gasoline derivatives, and total acids, and you can see that it is pretty useful. But what if we are interested in knowing much more detailed information about this pollution exposure, such as for example the level of benzene or the level of toluene which are potential carcinogens. So can we do that?
If you add a small separation column to the same device that we showed before, therefore we can do it, and this can be run in two minutes and still able to detect a few parts per billions of these carcinogen pollutants.
Here is an example of how these kind of devices can be used. So we have found, for example, that going into a casino generates a large exposure to toluene, which is due to the cigarette smoke exposure. If it happens that you have to go to the gasoline station, the exposure there to benzene is the largest that you can have, because of course the vapors are fresh and you have exposure to benzene which is a carcinogen at the five-part per billion level. Every time you drive on a highway, you can find high levels of exposure to benzene and acetyl benzene.
You can see senior the application of these devices.
This is how we can sense the air we breathe, but now what about what is in the air we breathe out, and how we can use the breath to sense what is going on within our body. So we breathe out carbon dioxide because we consume wood that we are basically like a fire. We use the food to generate the energy that we use to maintain our basic metabolic functions. This process generates carbon dioxide, and consume oxygen and therefore the oxygen consumption rate and the carbon dioxide production rate is proportionate to our resting energy expenditure that we can have throughout the day to maintain this function.
This is what we have been doing over the last two years, basically trying to bring a tool that we can sense the metabolism. Why why is metabolism important?
Basically the metabolism is important because it maintains a basic metabolic functions, and based on the energy that we expel during the day we can have pretty good estimations in how many calories we should be eating to maintain our weight, lose weight, or increase weight. So basically to reach a target weight.
Metabolism can be affected by many factors. As you can see here and that is why we consider it is important in tracking it.
Here is the tracker that we generate, and here I am going to run the application, which is the real device that we use in conjunction with the phone, through Bluetooth in order to get the information while the person is breathing. And this is an example on how a user can use the app.
Basically you sign in, and then you connect to a device and then you breath for a few minutes, so that your oxygen rate and carbon dioxide production rate is assessing. The application can calculate the metabolism level, and indicates whether your metabolism is normal, above, or below the average population. It is a personal measurement because this is normalized based on age, gender, height, and weight.
You can also have information regarding the energy source, whether you are burning carbs, fat or a mixed source. You can also share results with this app.
You will see the process here and sharing with some messages when we first carried out the metabolism tracking. This portion corresponds to the part of where you can get advice on how many calories you should be eating in order to reach a specific target weight. Basically, enter in your target weight, and your target exercise per week, and the diet regime, meaning at the rate in which you would like to apply the target weight.
This is a walk through the app, and this is basically a screenshot on the metabolism tracking and a screenshot of the respiratory tracking, which indicates the energy source as we said.
Now, how we can affect metabolism, and one way to affect metabolism strongly is through exercise. We have seen that by systematically in high intensity intermittent training can affect, and this means that this kind of training is fun training because it is basically taking a total of four minutes of your time. You can do it in your office, and we have tried it in the office. So if you have someone counting 20 seconds and you do reps then you rest for 10 seconds and then you go like that through eight rounds, basically you can get this training.
So, what happened when we had this training with our metabolism? So you can see here, this is my data and the blue line shows the metabolism level throughout the day in a non-heat day. In a heat day you can see it is just a small band, and if we normalize this data to a common baseline, you can see that there is some effect there, so for half an hour or so my metabolism increased about 300 kcal per day average.
So if we go to another individual. You can see here that the effect is different and the increase due to this training can be double. So everyone is different, even though we are applying the same training and the way to modify this metabolism is different.
I want to conclude this talk, saying that, based on our experience, we were able to create devices where we can track the level of pollutants, and especially carcinogen is that we are breathing in. Also create a tracker where we can track metabolism. All of these devices are portable, user friendly, and relatively low-cost and provide information in real time with a high reliability of activity.
The thing is that you can work with a big team trying to find the needle in the haystack, and we have found it for a few cases, and there is much more work that needs to be done. So we are very excited and still working on this personal device development. The team behind this of course everyone has a special role, and I really want to thank them, because it makes life really fun and I want to thank you for listening to this presentation.