KANSAS CITY, Mo. — Having fluid in your lungs can feel just like drowning. It’s a big problem for people with congestive heart failure. Now a vest is helping some people monitor their fluid levels and potentially stay out of the hospital.

After three heart attacks, Brenda Boyd’s heart has lost much of its pumping power, so she tires easily. The weakness of her heart also causes fluid to build up in her lungs.

“And then you can’t breathe. So it’s very debilitating,” she said, adding that it’s also frightening.

Daily weight checks are the standard way for people with congestive heart failure to monitor fluid retention, but they aren’t highly accurate. Now, as part of a study, Boyd slips on a vest once a day.

“This is really finding out the problem before it becomes a symptom for her,” said Dr. Andrew Kao, a cardiologist at Saint Luke’s Hospital.

The vest contains a device that sends radar signals through the chest to a sensor in back.

“And we can directly see into the middle part of the right lung as to how much fluid is in here,” said Dr. Kao.

It takes just 90 seconds to get a measurement. It’s automatically sent to the doctor’s office at Saint Luke’s through a secure web portal.

If there is too much fluid?

“They call and tell me what to do — take take an extra water pill or either come into their office for an IV diuretic,” said Boyd.

A chart of her measurements also helps the medical team see how she’s doing over time.

The goal is to keep patients out of the hospital. Boyd has had six stays for high fluid levels in recent years, but none since she started using the vest in April.

The study is still enrolling patients. It will see if those who get the vest are hospitalized less than those who don’t have it. If they are, it could become a tool for many more heart failure patients.