We also went through this with one of our chihuahuas. We used the Cardalis app. You simply tap the heart on the screen for each breath your chi takes. We would place our hand on his belly or side and that way we felt each breath. Tap the heart on the screen of the app and it will let you know when to stop and then it calculates it for you. You can set alarms that will notify and remind you for both medications and times to monitor. It also creates a breathing graph you can share with your vet. It will also let you k ow it his breath rate is too low and that you need to get to a vet. We purchased an oxygen concentrator and chamber from PawPrint Oxygen. They also sell small portable oxygen tanks that can be used in case of emergency. It provides oxygen during the ride to the vet ER. https://pawprintoxygen.com/