A novel mobile phone app being developed at Seattle Children’s and the University of Washington may transform care for patients with chronic lung diseases.

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Soon, patients with chronic lung diseases may be able to track their lung function any time simply by holding a smartphone at arm’s length and blowing.

Researchers at Seattle Children’s and the University of Washington (UW) are seeking FDA approval for SpiroSmart, a software application that essentially turns the microphone in any smartphone into a state-of-the-art spirometer.

“Spirometry is the one objective tool we use to assess and quantify lung function in people with asthma, cystic fibrosis and other chronic lung conditions,” says Dr. Margaret Rosenfeld, who until recently led the pulmonary function laboratory at Children’s and is part of the team working to bring SpiroSmart to market.

“If our patients could take high-quality lung function measurements at home – without having to invest in expensive equipment – we could identify and address problems before they cause real setbacks.”

Can you hear me now?

In most conventional spirometers, a turbine or other sensor measures how much air a patient blows into a tube over a specific time period, explains Dr. Shwetak Patel, the UW assistant professor of computer science and engineering who invented SpiroSmart.

SpiroSmart gets the same result without attaching a tube or any other hardware to the phone. Instead, it measures lung capacity by “listening” to the flow of air through a person’s body.

“The microphone picks up audio resonances as air flows through the airways,” says Patel. “We’ve developed algorithms that can detect subtle changes to tell us if airflow is restricted and determine overall flow. Instead of a turbine, SpiroSmart infers airflow by listening to the human body.”

In head-to-head comparisons in 52 healthy volunteers, SpiroSmart’s results came within 5% of those from a conventional spirometer costing thousands of dollars – well within the range that the medical community considers accurate.

Built-in coaching

Now Rosenfeld, along with Patel and a third partner, Dr. Jim Stout, are launching a two-phase clinical trial to test SpiroSmart in kids and adults with lung diseases.

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In the first phase, patients will test SpiroSmart against a conventional spirometer in a clinical setting; in the second phase, they will take SpiroSmart home to test how well they can measure their lung function in their daily lives.

Stout’s role is to help patients learn to take the best possible measurements. In addition to being a professor of Pediatrics at the UW and head of the asthma program at Odessa Brown Children’s Clinic, Stout is the founder of Spirometry 360, a web-based coaching system that helps primary care providers and their staff with the tricky business of accurately performing and interpreting spirometry readings.

His group is creating a new version of Spirometry 360 that will specifically help patients who use SpiroSmart continuously assess and improve the quality of the measurements they’re taking.

“Spirometry is easy to do wrong,” he says, “but, with training it’s not too hard to do well.”

Stout’s team will analyze the SpiroSmart readings patients download, flagging the ones that hint at problems with technique (for instance, a patient might be taking an extra breath or not breathing out hard enough). Those patients will receive one-on-one coaching.

The trial will yield data about how SpiroSmart measures up against conventional spirometers. If it works – and the FDA approves it – the team could begin evaluating how the app affects health outcomes.

Self-monitoring empowers patients

“SpiroSmart could be a game-changer for people living with chronic lung diseases,” says Patel.

“Patients with chronic conditions spend a tiny fraction of their lives at the doctor’s office,” adds Rosenfeld. “The rest of the time, they’re living their lives. SpiroSmart has the potential to do for patients with lung diseases what digital glucose monitors have done for people with diabetes: give them much more control over their own health.”

“SpiroSmart has the potential to do for patients with lung diseases what digital glucose monitors have for people with diabetes: give them much more control over their own health.”
– Dr. Margaret Rosenfeld