Nosocomial Infection Rates in Intensive Care Units from Seven Brazilian Hospitals: Decennial Trends

Background: in 1991 we introduced in some hospitals at Belo Horizonte, Brazil, a system for monitoring nosocomial infections (NI) that was based on the National Nosocomial Infection Surveillance – NNIS system. After almost twenty years this methodology, which is supported by specific software (SACIH), has been used by over 100 hospitals throughout the country.

Objective: to evaluate the incidence of device-associated nosocomial infections (NI), device utilization ratios (DU) and device average length of stay (d-LOS) in seven intensive care units (ICU), presenting an epidemiological profile that varies from three to fifteen years by applying the adult ICU component of the CDC/NNIS methodology.

Methods: prospective surveillance of NNIS patients according to the ICU NNIS component. The concepts of CDC have been used to characterize patients with NI. DU is the ratio between the number of each device-days and the number of patient-days. All device NI rates were calculated per 1,000 device-days. We calculated the percentiles 10% and 90% for the global NI rates, ICU NI risk, d-LOS, DU and device associated infection rates. These percentiles can be used as benchmarks.

Results: we enrolled 43,104 patients from all seven ICUs, representing 189,081 patient-days. During all period analyzed we diagnosed 8,049 NIs in 5,645 patients (43 NI per 1,000 patient-days and 13% NI risk). The percentiles 10% and 90% for d-LOS were:- urinary catheter average length of stay = [4 to 14] days, central line catheter average length of stay = [4 to 15] days, ventilator average length of stay = [4 to 21] days. The DU ratio were the following:- urinary catheter-DU ratio = [43% to 81%], central line catheter -DU ratio = [31% to 79%], ventilator-DU ratio = [27% to 70%]. The global NI rate per 1,000 patient-days range from [14 to 66] and  ICU NI risk  from [5% to 25%]; urinary catheter-associated infection  range from [0 to 20]; ventilator associated pneumonia from [0 to 49]; central line-associated blood stream infection = [0 to 9].

Conclusions: we analyzed and calculated benchmarks for the main epidemiological indicators for NI surveillance in adult and surgical ICUs. Catheter-associated urinary tract infection and ventilator-associated pneumonia are above the desirable standards of NNIS/NHSN system (90% percentile: 6.9 and 8.9, respectively).