National Hospital Discharge and Ambulatory Surgery Data
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National Survey of Ambulatory Surgery Description

The National Survey of Ambulatory Surgery (NSAS), which was initiated by the National Center for Health Statistics in 1994, is a national survey designed to meet the need for information about the use of ambulatory surgery services in the United States. For NSAS, ambulatory surgery refers to surgical and nonsurgical procedures performed on an ambulatory (outpatient) basis in a hospital or freestanding center’s general operating rooms, dedicated ambulatory surgery rooms, and other specialized rooms such as endoscopy units and cardiac catheterization labs. The survey was conducted annually from 1994 through 1996.

NSAS data for 1994, 1995, and 1996 include about 120,000 sampled visits annually from about 500 facilities. Data are available on patient characteristics including age and sex; administrative information including patient disposition, expected sources of payment, and region of the country where procedure was performed; and medical information including diagnoses and procedures performed coded using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). A detailed description of the NSAS is included in "Plan and Operation of the National Survey of Ambulatory Surgery," Vital and Health Statistics, Series 1, Number 37.
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Data from the NSAS are available for years 1994-96 and are used to examine important topics of interest in public health and for a variety of activities by governmental, scientific, academic, and commercial institutions. NSAS data are available in publications,  on public-use data tapes, CD-ROMs, and downloadable files from the FTP server.