Suitability of the NNIS index for estimating surgical-site infection risk at a small university hospital in Brazil.
OBJECTIVE
To detect the occurrence of surgical-site infection (SSI) in our study sample, using the traditional variables of the National Nosocomial Infection Surveillance (NNIS) index with a locally modified cut-off point for the "T time" defining length of surgical procedure; to compare the modified and the traditional NNIS index under the hypothesis that a cut-off point discriminating procedures of short and long duration, based upon the actual experience of the study sample, can adequately predict the risk of SSI.


METHODS
A retrospective chart review of 9,322 patients undergoing surgical procedures in the period January 1993 to December 1998. SETING: A small university hospital (UH) in southern Brazil.


RESULTS
The composite index using the local sample procedure-duration cut-off point (UH-index) performed better than any of the individual components of the composite index (anesthesia risk index and surgical-wound class [SWC]). The UH-index also predicted adequately the risk of SSI when compared to the traditional NNIS index, particularly when stratifying by SWC.


CONCLUSIONS
A modified NNIS index, using the sample cut-off point, can adequately predict the risk of SSI in a given population. Further studies are needed to compare and validate the NNIS index of risk for populations other than those of the NNIS-participating hospitals. Larger samples using different hospitals with similar characteristics are needed to investigate the risk of SSI associated with specific operations.
Campos
M L
ML
Infection Control Committee, Hospital Universitário, Universidade Federal de Santa Catarina, Florianópolis, Brazil.
Cipriano
Z M
ZM
Freitas
P F
PF
D001938:Brazil / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D008297:Male; D011159:Population Surveillance; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013530:Surgical Wound Infection / Q000453:epidemiology*