SCCM - Society of Critical Care Medicine

Should We Perform Surveillance of ICU Infections?

Stephan Harbarth, MD, MS*
Infection Control Program
Hôpitaux Universitaires de Genève
Geneva, Switzerland

Carlos Roberto Pérez Valdés, MD**
Infection Control Program
Hôpitaux Universitaires de Genève
Geneva, Switzerland

Nosocomial infections in the intensive care unit (ICU) are harmful for patients and expensive for society. Their rates vary considerably within and among hospitals by type of ICU. (1) Rates are generally lower in cardiac care units and higher in neonatal, surgical, trauma and burn units, reflecting the greater risk of infection in patients admitted to these latter types of units. Recently published surveillance data (2006 through 2007) from the Centers for Disease Control and Prevention’s (CDC) National Nosocomial Infections Surveillance system (now called the National Healthcare Safety Network) are shown in (Table 1), stratified by type of ICU and infectious condition. (2) In low to middle income countries, these incidence rates are much higher. (3)

Surveillance of ICU-acquired infections, with the goal of reducing infection rates and improving patient safety, has been integrated into processes of care and infection control for more than two decades, but this concept still is met with reservations from some clinicians and hospital administrators. Herein, we will highlight advantages and pitfalls of ICU-acquired infection surveillance for the interested critical care physician. We will neither describe surveillance of processes that are linked to cross-infection (e.g., hand hygiene), (4) nor cover the highly controversial subject of active surveillance for multidrug-resistant microorganisms. (5,6)

Advantages and Examples of Well-Conducted Surveillance
Surveillance for nosocomial infections, monitoring rates of infection and reporting results to personnel are important to ensure the quality of ICU care. Properly conducted surveillance can identify behavioral, environmental or treatment factors that, when corrected, will diminish endemic rates of infection in the unit. Additional benefits of concurrent surveillance include early identification and intervention in epidemics. (7) Several national and international networks have shown the benefit of conducting surveillance of ICUacquired infections in various settings, essentially by providing feedback to the concerned units and allowing corrective actions. (Table 2) lists the Web sites of a selection of national and international surveillance systems with components covering ICU-acquired infections.

The U.S.-based National Healthcare Safety Network, which is a CDC-driven reporting system, and the German Krankenhaus-Infektions Surveillance-System (KISS) are prominent examples of well-conducted, large-scale surveillance systems that have been established for many years. (2) Although both have methodological shortcomings and tend to underestimate the true incidence rates of nosocomial infections in ICUs, (8) they help to benchmark infection rates across different ICUs and to establish standards of preventive care. They have been particularly successful because they are confidential, voluntary and methodologically sound as they monitor infection rates, link to prevention efforts, and communicate data back to healthcare providers. Their sustained impact on reducing infection rates has been demonstrated in several reports. (9,10) For instance, Zuschneid et al evaluated trends in the rates of central venous catheter (CVC)- associated primary bloodstream infection in 84 German ICUs participating for more than 24 months in the German nosocomial infection surveillance system. (11) The study showed a decrease from 2.1 to 1.5 primary bloodstream infections per 1,000 CVC days, resulting in an overall relative reduction of 29% during the two-year observation period. However, not all surveillance networks are equally effective; data from a small U.S. network of 12 neonatal ICUs did not show significant changes in infection between 1992 and 2002. (12)

Limitations and Disadvantages of Current Surveillance Strategies
There are many challenges and disadvantages associated with current surveillance methods of monitoring ICUacquired infections, as summarized in (Table 3). Collection of individual patient-level data may yield excessive information, and is labor-intensive and time-consuming. Electronic data collection tools and information technology support could help reduce workload. (13) Without establishing sophisticated tools (e.g., control charts) and heightened awareness, regular surveillance activities may misinterpret random variation of ICU infections over time or miss clusters related to specific pathogens. Establishing specific alerting mechanisms (e.g., microbiology laboratory alerts) could help to reduce the latter risk. In addition, current case-finding strategies are focused largely on identifying infections manifested during an ICU stay; such strategies may not capture ICU-associated infections that are detected or had their onset after ICU discharge.

There is an increasing tendency to use surveillance data for internal and external benchmarking purposes. Internal or anonymous benchmarking within surveillance networks can provide impetus for further prevention efforts. Conversely, although public reporting of surveillance results has been mandated in several countries, it may be counterproductive in the long term. In our opinion, it does not make much sense to publish device-specific infection rates for different types of ICUs without providing appropriate case-mix risk adjustment and without considering other problems related to external benchmarking, especially in the case of ventilator-associated pneumonia. (14,15) Possible undesirable consequences may arise from publicly reporting ICU infection rates, such as shifting focus to short-term goals and introducing a tendency to hide, rather than to disclose, minor nosocomial infections. Low-scoring ICUs may even be punished for their commitment to retrieve unbiased data; in the worst case, ICUs that do the worst job of finding nosocomial infections would appear to be the best at prevention.

The Bottom Line
ICUs provide an ideal environment for the development and spread of nosocomial infections. Effective surveillance and the use of bundled sets of prevention practices shown to improve outcomes when performed consistently can reduce infections in ICUs profoundly. Several reports indicated that large national surveillance networks have been effective in reducing ICU-acquired infections by at least 20% to 30%, even without specific and dedicated prevention programs in each ICU. Nevertheless, many current ICU-associated infection surveillance strategies are labor-intensive and subject to limitations as a result of poor inter-rater reliability in applying standard definitions and variable implementation of case-finding strategies. (16) Strategies that make use of existing electronic data sources for creating process and outcome measures may have a number of important potential advantages, including decreasing the burden of data collection and reducing error introduced by poor inter-rater reliability.

Table 2: Surveillance Networks with ICU Components

Improving Patient Safety in Europe (IPSE)
Austria, Belgium, Germany, Spain, France, Lithuania, Luxemburg
http://ipse.univ-lyon1.fr/index.htm

International Nosocomial Infection Control Consortium (INICC)
www.inicc.org

Krankenhaus-Infektions-Surveillance-System (KISS)
Germany
www.nrz-hygiene.de
www.nrz-hygiene.de/english.htm (English language)

National Institute for Public Health and the Environment (RIVM)
The Netherlands
http://www.rivm.nl/en/aboutrivm/organization/cib/index.jsp

National Surveillance Study in Intensive Care Units
Spain
http://hws.vhebron.net/envin%2Dhelics/

Réseau d’alerte, d’investigation et de surveillance des
infections nosocomiales (Raisin)
France
www.invs.sante.fr/surveillance/raisin

Scottish Surveillance of Healthcare Associated Infection
Programme (SSHAIP)
Scotland
www.hps.scot.nhs.uk/haiic/sshaip/index.aspx

United States National Healthcare Safety Network [formerly
National Nosocomial Infections Surveillance System (NNIS)]
United States
http://www.cdc.gov/ncidod/dhqp/nhsn.html

References

1. Kritchevsky SB, et al. The impact of hospital practice on central venous catheter associated bloodstream infection rates at the patient and unit level: a multicenter study. Am J Med Qual. 2008;23:24-38.

2. Edwards JR, et al. National Healthcare Safety Network (NHSN) Report, data summary for 2006 through 2007, issued November 2008. Am J Infect Control. 2008;36:609-26.

3. Rosenthal VD, et al. International Nosocomial Infection Control Consortium report, data summary for 2002-2007, issued January 2008. Am J Infect Control. 2008;36:627-637.

4. Sax H, et al. Determinants of good adherence to hand hygiene among healthcare workers who have extensive exposure to hand hygiene campaigns. Infect Control Hosp Epidemiol. 2007;28:1267-1274.

5. Farr BM. Political versus epidemiological correctness. Infect Control Hosp Epidemiol. 2007;28:589-593.

6. Wenzel RP, et al. Screening for MRSA: a flawed hospital infection control intervention. Infect Control Hosp Epidemiol. 2008;29(11):1012 -1018.

7. Pittet D, et al. Hospital infections. In: Bennett JV, Brachman PS (eds.) 5th ed.The intensive care unit. Boston, Massachusets: Little Brown and Co.; 2007:373-394.

8. Rucker G, et al. Are KISS data representative of German intensive care units? Statistical issues. Methods Inf Med. 2006;45:424-429.

9. Centers for Disease Control and Prevention. Reduction in central line-associated bloodstream infections among patients in intensive care units--Pennsylvania, April 2001-March 2005. MMWR Morb Mortal Wkly Rep. 2005;54:1013-1016.

10. Zuschneid I, et al. Trends in ventilator-associated pneumonia rates within the German nosocomial infection surveillance system (KISS). Infect Control Hosp Epidemiol. 2007;28:314-318.

11. Zuschneid I, et al. Reducing central venous catheter-associated primary bloodstream infections in intensive care units is possible: data from the German nosocomial infection surveillance system. Infect Control Hosp Epidemiol. 2003;24:501-505.

12. Stoll BJ, et al. Infections in VLBW infants: studies from the NICHD Neonatal Research Network. Semin Perinatol. 2003;27:293-301.

13. Edwards JR, et al. Making use of electronic data: the National Healthcare Safety Network eSurveillance Initiative. Am J Infect Control. 2008;36:S21-26.

14. Eggimann P, et al. Ventilator-associated pneumonia: caveats for benchmarking. Intensive Care Med. 2003;29:2086-2089.

15. Klompas M, et al. Ventilator-associated pneumonia--the wrong quality measure for benchmarking. Ann Intern Med. 2007;147:803-805.

16. Hugonnet S, et al. Nosocomial bloodstream infection and clinical sepsis. Emerg Infect Dis. 2004;10:76-81.

Disclosures

*Author has no disclosures to report.

**Author has no disclosures to report.