The Maine Health Data Organization (MHDO) provides ambulatory surgery (AS) and emergency department (ED) records to HCUP in one combined outpatient file. The file also contains information on other services such as physical therapy and chemotherapy visits. Information on recurring visits which list several visits for the same type of scheduled procedure/treatment can be bundled into one record. Data from freestanding ambulatory surgery centers are not included.

Identifying Freestanding Facilities. The data element FREESTANDING identifies hospital-based and freestanding ambulatory surgery facilities.

Unusual Charge File for the Maine SASD. Maine provided a normalized line item charge detail file instead of the usual file with one observation per discharge with summary revenue and charge information. HCUP has retained the normalized file as provided with revenue codes, CPT/HCPCS codes, units, charges, and day of service.

The Maine SASD charge file contains more than one observation per discharge. Line item charge and service detail for a discharge should be summarized by the HCUP variable KEY which uniquely identifies a discharge. KEY can also be used to merge the detail charge information onto the discharge record in the Core file.

The Maine Health Data Organization provided outpatient records for ambulatory surgery and emergency department discharges in the same file. Discharges that did not include services to revenue codes in the range 450-459 (emergency room) were retained in the HCUP Maine SASD.

Records with a discharge disposition of "still a patient" were excluded from the HCUP Maine ambulatory surgery data. A quick analysis of these records indicate that these excluded records were interim records for physical therapy, psychotherapy, blood work, dialysis, and radiation therapy.

Using the standard HCUP criteria for assigning records to the SASD and SEDD, the source records are sorted as follows:

• 14.4% of source records are assigned to the SASD
• 15.9% of source records are included in the SEDD
• 68.7% of source records are sent to the STUF.