Critical Access Hospital Billing For Supplies

I understand that if you are and inpatient in a CAH you are not billed for most supplies. I get this for routine stuff like soap, tooth brush/paste, comb, bandaid but, I gave a patient a doughnut for her bum and it is not chargable. Sterile 4x4s for dressing changes are not chargable and for some patients with bid wound changes, you use a lot of them. Just wondering if other CAH practice the same. I understand that CMS has regulations and our finance dept. says that the charges are built into the bed charge however, some patients need more "stuff" than others. We are always struggling financially. Just seems that other than routine items should be chargeable.