If you are treated for sleep apnea with a cpac machine can you still use a benzo for sleep. Am ocd/bipolar and have been using klonopin (clonazepam) or ativan years?

Yes you can. Use CPAP and benzo. Positive airways pressure (cpap). It involves the use of a home-sleeping device that fits over the nose and applies continuous positive pressure into the airway to keep it open. Benzodiazepines provide short-term relief from insomnia. Adding a sleep hygiene, lifestyle and behavior changes to the mix could improve your sleep.
CPAP ; Benzo. Yes, it is possible to combine these two -- but benzos (klonopin, ativan, (lorazepam) etc) are not advisable for long periods due to tolerance ; dependence. You haven't listed your other medications for bipolar disorder or ocd, so i don't know what effect those may be having on your sleep or what other things have been tried. I agree with dr. Grin about need for sleep hygiene http://tinyurl.Com/lpcwhxt.