When I put my finger over the port where I connect my cannula on my portable oxygen concentrator, I don’t feel anything coming out – is something wrong?

Most POCs (G3/G4/G5, SimplyGo Mini, Freestyle Comfort) operate in what is called "Pulse Mode". In Pulse Mode, you will NOT feel anything coming out because it only dispenses oxygen when it detects a breath. Simply attach the cannula and begin breathing and then see if you can detect the "puff" of oxygen to your nose. If you put your cannula underwater in PULSE mode, you will not see bubbles because it will not detect a breath. For Inogen portable machines, you see a green light when it detects your breath, letting you know you've received a dose of oxygen.

It is easier for patients to detect the oxygen being dispensed on continuous flow like your home unit, SimplyGo or Eclipse 5 because they produce a steady stream of oxygen when powered on.