ECDC surveillance of surgical site infections (SSIs)

BACKGROUND

Surgical site infections (SSIs) are an important target for the surveillance of healthcare-associated infections (HAI). This surveillance is a priority for surveillance in several European countries. SSIs are among the most common HAI. They are associated with longer post-operative hospital stays, additional surgical procedures, may require intensive care and often result in higher mortality.

Seven surgical categories were selected for this surveillance: coronary artery bypass grafting, cholecystectomy, colon surgery, caesarean section, hip prosthesis, knee prosthesis and laminectomy.

OBJECTIVES

The primary objective for a hospital to participate in a national surveillance network of SSIs is to compare local infections rates to those of other hospitals and to follow-up infection rates over time.

The objectives at the national and the EU level are:

1. To provide the necessary reference data to make meaningful comparisons of risk-adjusted rates between units/hospitals
2. To followup trends in infection rates
3. To identify and followup risk factors of SSI.

At the EU level, the additional objectives are:

1. To describe the epidemiology and surveillance practices by country.
2. To work towards further harmonisation of surveillance methods.
3. To contribute to the further extension of the surveillance of SSIs in EU Member States.

METHODOLOGY

The ECDC HAISSI protocol for the surveillance of SSIs is based on the surveillance protocol developed by the HELICS (Hospitals in Europe for Infection Control through Surveillance) network  in 2000-2003. When adapting the HELICS protocol, the national HAI-Net surveillance contact points applied only minor changes.by. Hence, the data collected using the HELICS-SSI protocol are fully compatible with the ECDC HAISSI protocol. (The ECDC HAISSI protocol was integrated in the European surveillance system (TESSy)

The ECDC HAISSI protocol comes in two versions: 

1.  Patient-based (or “standard”) protocol: Patient-level data are collected for each patient/operation, whether there is an infection or not. The data includes risk factors that allow for risk-adjusted, inter-hospital comparisons.
2.  Unit-based (or “light”) protocol: Selected patient-level data are only collected for infected patients. Denominator data are collected by operation category (number of operations and postoperative patient-days). 

To improve the quality of inter-hospital comparisons, infection rates must be risk-adjusted so that variations due to differences in patient case-mix are reduced. Therefore, the patient-based (“standard”) protocol is the recommended method for surveillance.

However, the unit-based (“light”) protocol is less labour intensive and requires less resources.The protocol can be used when surveillance resources are scarcesince surveillance of SSIs must be carried out over long periods to stabilise confidence intervals of SSI rates. All indicators generated from data obtained with the unit-based (“light”) protocol can also be generated from data obtained with the patient-based (“standard”) protocol. Therefore, both types of data collection may be combined within a country or even in the same hospital (although not during the same surveillance period).

ECDC supports the maintenance of the hospital data collection software HELICSwin (MS Access application) through a contract with the Scientific Institute of Public Health in Belgium. This software allows collection and analysis of data according to the ECDC HAISSI protocol at the hospital level. It can be translated and is made available to national surveillance networks without charge.

A login and password to download the software can be obtained by national surveillance networks and pilot hospitals by contacting ECDC: hainet@ecdc.europa.eu.

PUBLICATIONS

European data on surveillance of SSIs have been published since 2008 in the chapter on HAI as part of ECDC’s Annual Epidemiological Report. Chapter 2.6: Antimicrobial resistance and healthcare-associated infections, Annual Epidemiological Report 2010

HAI-Net protocols and more documents are available for national HAI surveillance contact points and experts on the HAI-Net Extranet.