TOTAL_AS_ENCOUNTERS indicates the total number of AS encounter records from this hospital with at least one narrow or "major" surgery.

HCUP Surgery Flag Software for Services and Procedures was used to identify surgical procedures of interest for the NASS. The Surgery Flag Software processes CPT procedure codes and classifies them as narrow, broad, or neither. The NASS focuses on surgeries in the narrow class, or major ambulatory surgeries. The narrowly defined flag (narrow flag) is the most targeted and restrictive surgical identifier, consisting of invasive therapeutic surgical procedures. A "narrow" procedure (1) involves incision, excision, manipulation, or suturing of tissue that penetrates or breaks the skin; (2) typically requires use of an operating room; and (3) requires regional anesthesia, general anesthesia, or sedation to control pain.