If you’re unlucky enough to have a heart attack, you may be prescribed a portable defibrillator. The device, which patients wear with a harness around their chest, senses for irregular rhythms and delivers a quick shock if needed. It’s a vital stop-gap while people are waiting for a permanent pacemaker implant.
It’s not an ideal solution, though–at least not according to a team of students at Johns Hopkins. When they asked clinicians if patients liked wearing the defibrillators, many said they didn’t. “The problem is that there is a high patient non-compliance for wearable defibrillators,” says Sandya Subramanian, the team leader. “We asked patients and clinicians why, and they said it was because of convenience, weight, comfort, and false alarms.” Two studies show that up to 20% of patients didn’t keep it on for the time they were supposed to.
The students set out to build an alternative and came up with a T-shirt-based device that distributes weight more evenly than today’s technology (like this defibrillator from Zoll). Instead of a hefty box-controller that patients wear on their waistband, the vest has pockets on either wing. There’s also a wrist-band monitor that warns patients 30 seconds before the defibrillator is about to go off. That way, they can short-circuit the mechanism if they feel it’s a false alarm.
“The main thing is we wanted to do is get rid of that box type thing. So we integrated a lot of those electronics into the shirt itself, mainly in two pockets on either side,” Subramanian says. “We’re not changing the way the defibrillator works. We’re reconfiguring it and putting it into a different form, so it’s easier for the person to carry around.”
Typically, a patient would wear the defibrillator for at least 23 hours a day–every moment they’re not in the shower. That means it needs to be comfortable and not feel like nanny-wear. The new device weighs considerably less than the standard products on the market today, which are three pounds and more.
Subramanian, who just finished her junior year, plans to keep working on the vest through her time at Johns Hopkins. “We definitely want to try and get this out there but it involves a lot of testing and reiterations of prototypes,” she says.