Two outcome measures include line related BSIs

Lack of discharge surveillance may confound SSIs

A draft guidance document by the Centers for Disease Control and Prevention’s Healthcare Infection Control Practices Advisory Committee recommended two outcome measures for mandatory public reporting systems on health care-associated infections. The draft lists the following details on the those selections, including measures, rationale for inclusion, and potential limitations.

1. Central line-associated laboratory-confirmed primary bloodstream infection (CLA-LCBI).

Measures:

  • Numerator: Number of CLA-LCBI.
  • Denominator: Number of central-line days in each population at risk, expressed per 1,000.
  • Populations at risk: Patients with central lines cared for in different types of intensive care units (ICUs).
  • Risk stratification: By type of ICU.
  • Frequency of monitoring: At least six months per year, unless ICU has five beds or less, then every month.
  • Frequency of rate calculation: Monthly (or quarterly for small ICUs) for internal hospital quality improvement purposes.
  • Frequency of rate reporting: Annually using all the data to calculate the rate.

Rationale for Inclusion:

Overall, an infrequent event but one that is associated with substantial cost, morbidity, and mortality. Reliable laboratory test available for identification (i.e., positive blood culture). Prevention guidelines exist and insertion processes can be monitored concurrently. Sensitivity: 85%; positive predictive value: 75%.

Potential Limitations:

LCBI can be challenging to diagnose since the definition includes criteria that are difficult to interpret (e.g., single-positive blood cultures from skin commensal organisms may not represent true infections.) To offset this limitation, a system could include only those CLA-LCBI identified by criterion in the LCBI case definition, which will result in smaller numerators and, therefore, will require longer periods of time for sufficient data accumulation for rates to become stable/meaningful. Standard definition of central line requires knowing where the tip of the line terminates, which is not always documented and can, therefore, lead to misclassification of lines.

2. Surgical site infection (SSI).

Measures:

  • Numerator: Number of SSIs for each specific type of operation.
  • Denominator: Total number of each specific type of operation, expressed per 100.
  • Risk stratification: Focus on high-volume operations and stratify by type of operation and National Nosocomial Infections Surveillance (NNIS) SSI risk index.
  • Alternate risk adjustment: For low-volume operations, by standardized infection ratio.

Rationale for Inclusion:

Low frequency event but one that is associated with substantial cost, morbidity, and mortality. Prevention guidelines exist and certain important processes can be monitored concurrently. Sensitivity: 67%; positive predictive value: 73%.

Potential Limitations:

Rates are dependent on surveillance intensity, especially completeness of post-discharge surveillance (50% of SSIs become evident after discharge and may not be detected). SSI definitions include a "physician diagnosis" criterion, which reduces objectivity.