ICD-9-CM procedures from the State Inpatient Databases (SID) are retained in the data elements PR_IP1 to PR_IP9.
While nine ICD-9-CM procedures per ED inpatient event are retained in the NEDS, the number of code fields populated varies. While some States report more than the nine ICD-9-CM procedures, less than 2% of all ED inpatient records report more than nine procedure fields. The data element NPR_IP lists the number of ICD-9-CM procedures reported on the original SID record.
The original value of the ICD-9-CM first listed procedure (PR_IP1), whether blank or coded, is retained in the first position of the procedure vector. Starting at the first secondary procedure (PR_IP2), the procedures are shifted during HCUP processing to eliminate blank secondary procedures. For example, if PR_IP2 and PR_IP4 contain non-missing procedures and PR_IP3 is blank, then the value of PR_IP4 is shifted into PR_IP3. Secondary procedures are never shifted into the first listed position (PR_IP1).
Validity and consistency checks for the procedure are consistent with all other HCUP databases.