A practical tool to assess the incidence of nosocomial infection in Japanese intensive care units: the Japanese Nosocomial Infection Surveillance System

SummaryInfection control professionals have the means to calculate infection rates in their hospitals but not to assess them. They require a practical tool that enables them to compare observed infection rates with external standards. Based on the data obtained from the intensive care unit (ICU) component of the Japanese Nosocomial Infection Surveillance (JANIS) system, a spreadsheet was developed to calculate a standardized infection ratio (SIR) as a risk-adjusted indicator. Out of the factors associated with the development of nosocomial infections in a multi-variate analysis, the following three factors were selected for stratification: APACHE II score (0–10, 11–20, 21+), operation (yes, no) and ventilator use (user, non-user). Infection rates in 2001 were determined (per 1000 patient-days), stratified by the three factors, as a benchmark. The spreadsheet was designed to calculate SIRs on the basis of the Japanese benchmark infection rates using Microsoft Excel software. The user of the spreadsheet should input the number of observed nosocomial infections and patient-days by APACHE II score, operation and ventilator use. When applied to eight Japanese ICUs, the spreadsheet revealed relative differences and temporal changes in the incidence of nosocomial infections within these ICUs.