I'm not sure about your other payers, but Medicare will not pay an ASC for a canceled procedure unless the patient has already been taken to the procedure room. Here are the guidelines from the Medicare Claims Processing Manual:
A. Contractors deny payment when an ASC submits a claim for a procedure that is terminated before the patient is taken into the treatment or operating room. For example, payment is denied if scheduled surgery is canceled or postponed because the patient on intake complains of a cold or flu.
B. Contractors pay 50 percent of the rate if a surgical procedure is terminated due to the onset of medical complications after the patient has been prepared for surgery and taken to the operating room but before anesthesia has been induced or the procedure initiated (use modifier 73). For example, 50 percent is paid if the patient develops an allergic reaction to a drug administered by the ASC prior to surgery.... Facilities use a 73 modifier to indicate that the procedure was terminated prior to induction of anesthesia or initiation of the procedure.
C. Contractors make full payment of the surgical procedure if a medical complication arises which causes the procedure to be terminated after anesthesia has been induced or the procedure initiated (use modifier -74). For example, A/B MACs (B) make full payment if, after anesthesia has been accomplished and the surgeon has made a preliminary incision, the patient’s blood pressure increases suddenly and the surgery is terminated to avoid increasing surgical risk to the patient. In this case, the resources of the facility are consumed in essentially the same manner and to the same extent as they would have been had the surgery been completed. Facilities use a 74 modifier to indicate that the procedure was terminated after administration of anesthesia or initiation of the procedure.