Hi mnsleep, Welcome to Apnea Board!
This sounds like a rare problem. I hope someone who has similar issues can respond, but my guess is that not many people who have an artificial tear duct are using CPAP.
I did a fairly extensive search on the Internet and really couldn't find anything useful for you. I would go to the doctor who put in the artificial duct and tell him/her of the CPAP issues - if they aren't competent, it might be worth it to make a trip to a larger city with better doctors.
Before he gets the trach, check out this page, which ConnCarl has suggested in the past:
http://www.peaceful-river.com/osa/index.htmHopefully, others with more experience can chime in on this problem.