Much work has been done to standardize cardiac arrest outcome measures in an effort to facilitate comparisons across EMS systems, states, and regions.^14,16 Although an SCA registry can be built using proprietary database programs such as Microsoft Access, this requires time and some degree of database development skill. A number of existing EMS data collection systems are in use throughout the U.S. and Canada designed for similar purposes, also adhere to these definitions. Among the most well known are: NEMSIS, ARIZONA SHARE, CARES, and ROC EPISTRY.

The majority of the registries mentioned here have been developed for a specific geographic area or for research. As such, they may not be accepting data. NEMSIS is in use in various degrees of functionality for data collection in most states.

Some EMS systems have anticipated the importance of the SCA registry and have either designed their own database or use a proprietary system. Whichever method is used, it is important that data be collected using standardized methods. There must also be documented, precise 38 definitions for all elements included in the data dictionary. See the Appendix for the HeartRescue Partners data dictionary.