Healthy App Measures Lung Function
September 24, 2012

New Health App For Smartphones Measures Lung Function

Lee Rannals for - Your Universe Online

As part of an increasingly popular trend toward health-focused smartphone applications, a new iPhone app allows people to measure their lung function directly through their smartphones.

Researchers at the University of Washington, UW Medicine and Seattle Children's Hospital developed the application to allow people to monitor their lung function at home or on the go by simply blowing into their phone.

Typically, people who suffer from asthma or other chronic lung problems have to go to a doctor or clinic to have their lung function measured.  The new application will allow for more frequent testing in the hopes of detecting problems even earlier.

“There´s a big need in the pulmonary community to make testing cheaper and more convenient,” lead researcher Shwetak Patel, a UW assistant professor of computer science and engineering and of electrical engineering, said in a press release.

“Other people have been working on attachments for the mobile phone that you can blow into. We said, ℠Let´s just try to figure out how to do it with the microphone that´s already there.´”

Other smartphone apps claim to measure lung function, but they do things like measure how loud the exhaled breath sounds, which can vary depending on how close to their mouth a person holds the phone thus making them inaccurate.

There are also lung function testing systems that are available for at-home use, but these typically cost hundreds of dollars and can be difficult to use.

The team's new application comes after a two-and-a-half year project that involved experimenting with how to get an accurate measurement of lung function using just a smartphone.

At the doctor's office, a spirometer measures how much and how fast the person can breath out, which indicate to doctors if the patient´s airways are narrowed or filled with mucous.

The team said they found they could model a person's trachea and vocal tract as a system of tubes to replace the spirometer, and use a phone to analyze the sound wave frequencies to detect when the breath is resonating in those natural pipes.

“There are resonances that occur in the signal that tells you about how much flow is going through the trachea and the vocal tract, and that´s precisely the quantity that a clinician needs to know,” Patel said in the release.

The team tested the system on 52 mostly healthy volunteers on an Apple iPhone 4S using its built-in microphone.  They were able to produce an accuracy that came within 5.1 percent of a commercial portable spirometer that costs thousands of dollars.

“The tests are very promising,” co-author Dr. Margaret Rosenfeld, an associate professor at UW Medicine and a pulmonary specialist at Seattle Children´s Hospital, said in a press release. “Both providers and patients are very excited” about the possibility of home tests, she added.

The Coulter Foundation is providing a grant that will allow more clinical testing with patients of varying ages and lung health, which could help get the U.S. Food and Drug Administration's seal of approval that will be needed to bring the app to the market.

“Portable glucometers have dramatically changed glucose monitoring and improved the quality of life for people with diabetes,” Patel said in the release. “We hope to do the same thing for pulmonary disorders.”