Google research scientist Jake Sunshine sat down with MobiHealthNews at Google's Bay View headquarters on Tuesday during the tech giant's Made by Google event to discuss the first-of-its-kind loss of pulse detection technology available on the Pixel Watch 3. 

The feature, initially available in the E.U. and U.K., detects signs of a loss of pulse, turns on infrared and red lights, and then looks for additional signs of a pulse. A motion sensor then looks for signs of movement. 

An AI algorithm then analyzes the pulse and movement signals to confirm a loss of pulse, which triggers a countdown to see if the user responds. If not, the watch sends an automated message to emergency services with the user's status and location.

MobiHealthNews: Can you tell our readers about the loss-of-pulse-detection technology and how it was created?

Jake Sunshine: So, loss of pulse is a condition that can happen to anyone (people who are younger, people who are older), and it can happen for a variety of causes, both inside and outside of the heart. A big challenge is that it is a time-sensitive emergency, and we know that a lot of people experience these events when no one is around. So, we built something to try to identify when these events occur and to try to connect people with help faster, especially if no one's around, because that would be the most helpful scenario.  

The sensors we use to do this include the heart rate sensor, which is based on the optics that are in the watch, and then the motion sensor. And we bring those together using machine learning and AI to identify when someone makes a transition from a pulsatile state to a loss-of-pulse state. 

MHN: How did you research the accuracy and effectiveness of the technology? 

Sunshine: It's a big challenge, because we can't just have people make their hearts stop for us to do our testing. So, we worked with a lot of external partners to get input on the feature because it's so consequential.

We spoke with cardiologists, resuscitation scientists, EMS providers, people who field 911 calls, and then actual people who respond to these emergencies. We wanted to get the totality of perspectives to build something that was responsible and could meet the needs of users.

MHN: When a loss of pulse is detected, the watch sends an automated message to emergency services. What does the message say?

Sunshine: Similar to other features in the Android safety portfolio and safety portfolio for Pixel, it can send a message that says that a user's pulse is no longer detected and that they are not responsive. And so, that combination, and then their location and other features. That's the gist of the message.

It gets back to us really trying to recognize a big challenge that's costing a lot of lives, and then building something that is also responsible. That required getting input from this huge emergency response ecosystem to make sure that what we were building was responsible. So, we got that feedback along the way before getting to a point where we were confident in the technology.

The other important thing is that this is a really consequential event. So, we are working with regulators to make sure it meets a high enough bar for that. And so,this is launching first in select European countries, and the U.K., and we hope to bring it to more people in different countries.  

MHN: Why is it launching in the E.U. and U.K. first? Is that due to regulations?

Sunshine: No. We want to get it to as many people as possible, and there are different regulatory agencies in different places, so this is our first market, and we hope to bring it to subsequent markets later on. 

Recognizing that this is a big research challenge, we went about this in a way that we thought was responsible, and we're getting feedback from outside experts, as well as bringing this before regulators. That's been our approach to trying to solve this problem. 

And, like any system, this won't detect every event. No system can, but what we're trying to do is to be as helpful as we can with this really challenging problem. So, we're trying to be helpful, and we're trying to build innovative technology responsibly to help solve this problem.

MHN: Is there anything else you want to add for our readers that has not been covered?

Sunshine: To emphasize that this is a first-of-its-kind feature that's bold and responsible, and applies to a really challenging problem. We've done everything we can to build this responsibly with all the feedback necessary to build a consequential system like this before releasing it.