Your CPAP will use 5amps (60 watts) max. That's if it's at the highest cfm setting, which is very rare. My wifes is set at 6 cfm and it takes about 35 watts. So, yes you can use that 12v TV outlet, no problem. If your TV is an LCD or LED, you could use both at the same time with a 12v Y adapter.
I believe wa8yxm, was referring to the dash 12v outlet, so you could use that if you ever wanted to sleep while driving
If that TV outlet isn't convienient for you, PM me and I'll explain how I set one up next to the bed.