When a patient is experiencing heart failure, water often begins to collect in their lungs, producing a sensation that some have described as similar to drowning. In order to assess whether or not is safe for these patients to be discharged from the hospital, doctors must measure the amount of fluid in the lungs– a cumbersome task as traditional methods are costly, difficult to perform, and often provide unreliable results. Now, a team from the University of Hawaii is working to develop a stethoscope that works with a microwave sensor to determine the amount of water in a patient’s lungs. The coin-sized monitor measures not only lung-water, but heart rate, breathing, and volume of blood pumped per beat. While there is still doubt about the device’s ability to continuously monitor water levels in the lungs, as well as whether or not the device would work equally well on patients of all sizes, developers are hopeful for the potential of the device.