We bill the regular D-codes, as we've been told there are no associated CPT codes we can bill, since there are none for anesthesia done by a provider in an office setting (oral surgery is the only specialty that's allowed to administer it's own anesthesia). We do not, however, have any success with Medicare paying for those codes; they deny completely to PR.
Also, we've been billing in units because that is what our local BCBS requires. They are the only one that really cares, so we've followed their rules all around. Since Medicare denies as a PR-204, they seem fine with it (otherwise they'd deny as a CO and tell us we didn't submit the code correctly).