"With SpiroCall, you can call a 1-800 number, blow into the phone and use the telephone network to test your lung function," Patel said.
The patients take a deep breath in and exhale as hard and fast as they can until they can't exhale any more. The phone's microphone senses sound and pressure from that exhalation and sends the data to a central server, which uses machine learning algorithms to convert the data into standard measurements of lung function. "People have to manage chronic lung diseases for their entire lives," lead author Mayank Goel, computer science and engineering doctoral student at University of Washington, said. "So there's a real need to have a device that allows patients to accurately monitor their condition at home without having to constantly visit a medical clinic, which in some places requires hours or days of travel," Goel noted. SpiroCall is an advancement over SpiroSmart which the researchers introduced in 2012 to let people monitor their lung function by blowing into their smartphones. Over the last four years, the team has collected data from more than 4,000 patients who have visited clinics in Seattle and Tacoma as well as in India and Bangladesh, where clinicians have measured lung function using both SpiroSmart and a commercial spirometer. In surveying patients from India and Bangladesh, though, the team realised that a significant percentage did not own smartphones and would be unable to use SpiroSmart in their own homes -- which was a key goal of the project. The team realised that the only sensor they were using was a microphone, which all phones have.
So the researchers decided to develop a system that would work with any phone anywhere in the world by having the patient use a call-in service. How the tool meets the medical community’s standards for accuracy will be described in a paper to be presented in May at the Association for Computing Machinery's CHI 2016 conference in San Jose, California.