Does Resmed recommend using an anti-backflow device for oxygen use with a pap unit? I’ve seen it done both with and w/o for years but wondered what Resmed suggests.

We don’t have a specific anti-backflow device we recommend. The oxygen connector port directs oxygen in the direction of air flow within the device so if the machine is on it will be taken in the correct direction. For oxygen to flow back into the FG, the tube and mask would have to fill with oxygen first and for that to happen the machine would typically have to be off. If the machine is off the risk of an unexpected electrical failure is likely far lower than when the machine is on, which is already extremely low. With relatively low volumes of oxygen used i.e. approx. < 4l/min then this risk is even further reduced.