Source: NHSN Data - April through June, 2011
To view technical notes, including information on hospitals not seen on the map, see SSI-Tech-Tables-2011-Q2 
About Surgical Site Infections
Surgical Site Infections (SSIs) are infections that occur following surgery. Infections are classified according to their location in the body.
- Superficial (the skin around the incision)
- Deep (muscles or other tissue along the incision path)
- Organ/Space (the organs or internal area that is the subject of the surgery)
Deep and organ/space SSIs are less frequent, but can be more serious than superficial SSIs.
Key Terms
Confidence Interval (CI): A CI gives you a range of values likely to include the actual SIR, given the single calculated value of the estimated SIR. The more procedures the hospital performs, the more precise the estimate of the true value for the SIR becomes, and the confidence intervals become narrower. The SIRs that you see on the map show 95% confidence intervals. That means that there is a 95% chance that the true value for the SIR that is reported is somewhere between the upper and lower limits of the interval. The SIR is not significantly different from 1, or what is predicted for that hospital, if 1 is between the upper and lower limits. In future reports a greater number of procedures will be included, and the confidence intervals will become narrower as the estimate of the true SIR becomes more precise.
Risk Adjustment: California law also requires risk adjusting the SSI information, which ensures more accurate and fair comparisons. The risk of an SSI can be increased by factors that are not under the control of the hospital, such as a patient having diabetes. Some hospitals may perform surgery on more patients with such risk factors than other hospitals. Risk adjustment is a means to correct or adjust for the differences in these risks among patients when reporting outcomes such as SSIs.
Standardized Infection Ratio (SIR): The method for risk adjusting used here is the NHSN Standardized Infection Ratio (SIR). The SIR compares the actual number of SSIs at each hospital to a predicted number of SSIs based on that hospital's patient population risks for those infections and standard rates. The standard rate for this report is the average infection rate of all hospitals who reported their rates to the NHSN database from 2006-2008. The SIR used in this report is for deep and organ/space infections. This ratio can be used to compare one hospital’s performance to the national standard and how it changes over time. For this brief reporting period, none of the hospitals had infection rates that were significantly different from the predicted rate based on the national average and the hospital’s patients’ health and surgery.
National Healthcare Safety Network (NHSN) is a secure, internet-based system for infection reporting by healthcare facilities operated by the Centers for Disease Control and Prevention (CDC).
The Office of Statewide Health Planning and Development (OSHPD) is one of 13 departments within the California Health and Human Services Agency. OSHPD administers programs whose purpose is to implement the vision of "equitable healthcare accessibility for California." Office of Statewide Health Planning and Development (OSHPD)
For information on surgical site infection prevention measures, see Mandatory Reporting of Surgical Site Infection Prevention Measures
If you have suggestions or questions about how this SSI data is presented please contact the CDPH HAI Program: cdphhaiprogram@cdph.ca.gov