Always inform the screener that you have a cpap, and it must be removed from its case, per TSA policy.
https://www.tsa.gov/traveler-informa...paps-and-apaps
Passengers are required to remove CPAPs, BiPAPs, and APAPs from its carrying case, though facemasks and tubing can remain in the case. A passenger can provide a clear plastic bag in which to place the CPAP, BiPAP or APAP during X-ray screening; however, an officer [sic] may need to remove the CPAP, BiPAP or APAP from the bag to test it for traces of explosives.
I've removed my liquids baggy from my carryon maybe 3-4 times in the last year, spanning probably 70 flights. I only do so when they explicitly state that everyone must do so. That's a rare occurrence for me.