The ICU-HELICS programme: towards European surveillance of hospital-acquired infections in intensive care units

Comprehensive analysis of rule formalisms to represent clinical guidelines: Selection criteria and case study on antibiotic clinical guidelines

BACKGROUND

The over-use of antibiotics in clinical domains is causing an alarming increase in bacterial resistance, thus endangering their effectiveness as regards the treatment of highly recurring severe infectious diseases. Whilst Clinical Guidelines (CGs) focus on the correct prescription of antibiotics in a narrative form, Clinical Decision Support Systems (CDSS) operationalize the knowledge contained in CGs in the form of rules at the point of care. Despite the efforts made to computerize CGs, there is still a gap between CGs and the myriad of rule technologies (based on different logic formalisms) that are available to implement CDSSs in real clinical settings.

OBJECTIVE

To helpCDSS designers to determine the most suitable rule-based technology (medical-oriented rules, production rules and semantic web rules) with which to model knowledge from CGs for the prescription of antibiotics. We propose a framework of criteria for this purpose that is extensible to more generic CGs.

MATERIALS AND METHODS

Our proposal is based on the identification of core technical requirements extracted from both literature and the analysis of CGs for antibiotics, establishing three dimensions for analysis: language expressivity, interoperability and industrial aspects. We present a case study regarding the John Hopkins Hospital (JHH) Antibiotic Guidelines for Urinary Tract Infection (UTI), a highly recurring hospital acquired infection. We have adopted our framework of criteria in order to analyse and implement these CGs using various rule technologies: HL7 Arden Syntax, general-purpose Production Rules System (Drools), HL7 standard Rule Interchange Format (RIF), Semantic Web Rule Language (SWRL) and SParql Inference Notation (SPIN) rule extensions (implementing our own ontology for UTI).

RESULTS

We have identified the main criteria required to attain a maintainable and cost-affordable computable knowledge representation for CGs. We have represented the JHH UTI CGs knowledge in a total of 12 Arden Syntax MLMs, 81 Drools rules and 154 ontology classes, properties and individuals. Our experiments confirm the relevance of the proposed set of criteria and show the level of compliance of the different rule technologies with the JHH UTI CGs knowledge representation.

CONCLUSIONS

The proposed framework of criteria may help clinical institutions to select the most suitable rule technology for the representation of CGs in general, and for the antibiotic prescription domain in particular, depicting the main aspects that lead to Computer Interpretable Guidelines (CIGs), such as Logic expressivity (Open/Closed World Assumption, Negation-As-Failure), Temporal Reasoning and Interoperability with existing HIS and clinical workflow. Future work will focus on providing clinicians with suggestions regarding new potential steps for CGs, considering process mining approaches and CGs Process Workflows, the use of HL7 FHIR for HIS interoperability and the representation of Knowledge-as- a-Service (KaaS).

Conversion of Prevalence Survey Data on Nosocomial Infections to Incidence Estimates: A Simplified Tool for Surveillance?

We calculated the incidence of nosocomial infection in 2 intensive care units (ICUs) on the basis of prevalence data recorded from 1997 through 2002 and compared these estimates to cumulative incidences measured in the 2 ICUs during the same period to investigate the feasibility and the reliability of converting prevalence data to incidence estimates. Decreases in the calculated and measured incidences over time in the ICUs were found to be statistically significantly related.

Integrating intensive care unit (ICU) surveillance into an ICU clinical care electronic system

The intensive care unit (ICU) is the specialty with the highest prevalence of healthcare-associated infection (HCAI) in European hospitals and therefore a priority for surveillance of HCAI. Whereas surveillance is an essential part of an effective infection prevention and control (IPC) programme, all too often it consumes too much clinician and IPC team time, limiting the time available for quality improvement. The case for electronic surveillance is made in the literature from several countries on this basis. These studies indicate that electronic surveillance can improve validity, reduce time spent on surveillance, and provide opportunities for improvement in clinical decision-making and IPC action arising from surveillance. The Scottish ICU HAI surveillance system was established as part of an integrated audit and clinical care system. Investment in this technology infrastructure reduced the burden of data collection and has resulted in a focus on driving improvement in all Scottish ICUs. The experience in Scotland indicates that several critical components are necessary to optimize ICU HCAI surveillance, including: nationally agreed definitions and methods; national investment in information technology infrastructure to make it easier to follow clinical care pathways; leadership of surveillance by intensivists; piloting and validation to ensure confidence in the system; and strategic integration of national and local programmes. These elements have helped improve surveillance data locally, nationally, and at a European level, allowing clinical attention to be focused on the data rather than on the process of data collection.

A biomarker panel (Bioscore) incorporating monocytic surface and soluble TREM-1 has high discriminative value for ventilator-associated pneumonia: a prospective observational study

INTRODUCTION

Ventilator-associated pneumonia (VAP) increases mortality in critical illness. However, clinical diagnostic uncertainty persists. We hypothesised that measuring cell-surface and soluble inflammatory markers, incorporating Triggering Receptor Expressed by Myeloid cells (TREM)-1, would improve diagnostic accuracy.

METHODS

A single centre prospective observational study, set in a University Hospital medical-surgical intensive Care unit, recruited 91 patients into 3 groups: 27 patients with VAP, 33 ventilated controls without evidence of pulmonary sepsis (non-VAP), and 31 non-ventilated controls (NVC), without clinical infection, attending for bronchoscopy. Paired samples of Bronchiolo-alveolar lavage fluid (BALF) and blood from each subject were analysed for putative biomarkers of infection: Cellular (TREM-1, CD11b and CD62L) and soluble (IL-1β, IL-6, IL-8, sTREM-1, Procalcitonin). Expression of cellular markers on monocytes and neutrophils were measured by flow cytometry. Soluble inflammatory markers were determined by ELISA. A biomarker panel ('Bioscore'), was constructed, tested and validated, using Fisher's discriminant function analysis, to assess its value in distinguishing VAP from non VAP.

RESULTS

The expression of TREM-1 on monocytes (mTREM-1) and neutrophils (nTREM-1) and concentrations of IL-1β, IL-8, and sTREM-1 in BALF were significantly higher in VAP compared with non-VAP and NVC (p<0.001). The BALF/blood mTREM-1 was significantly higher in VAP patients compared to non-VAP and NVC (0.8 v 0.4 v 0.3 p<0.001). A seven marker Bioscore (BALF/blood ratio mTREM-1 and mCD11b, BALF sTREM-1, IL-8 and IL-1β, and serum CRP and IL-6) correctly identified 88.9% of VAP cases and 100% of non-VAP cases.

CONCLUSION

A 7-marker bioscore, incorporating cellular and soluble TREM-1, accurately discriminates VAP from non-pulmonary infection.

[Healthcare-associated infection rates: measuring and comparing. Experiences from the German National Nosocomial Infection Surveillance System (KISS) and from other surveillance systems]

Surveillance of nosocomial infections is meanwhile a cornerstone of infection prevention activities in hospitals. The objective of this article is to compare healthcare-associated infection rates in intensive care patients, neonatal intensive care patients and operated patients (ICU-KISS, OP-KISS, NEO-KISS) of the German nosocomial infection surveillance system (KISS) with the corresponding data of the US American National Healthcare Safety Network (NHSN) and the European Centre for Disease Prevention and Control (ECDC). In general, the methodological differences among the three surveillance systems are minor but there are some exceptions. Therefore, differences between countries have to be interpreted very carefully as they may be due to differences in diagnostics, patient mix, types of interventions, length of stay, selection of participating hospitals, post-discharge surveillance activities and interpretation of case definitions. Organizational aspects, such as mandatory participation with public disclosure on infection rates may also have an impact.

Concordance between European and US case definitions of healthcare-associated infections

Background

Surveillance of healthcare-associated infections (HAI) is a valuable measure to decrease infection rates. Across Europe, inter-country comparisons of HAI rates seem limited because some countries use US definitions from the US Centers for Disease Control and Prevention (CDC/NHSN) while other countries use European definitions from the Hospitals in Europe Link for Infection Control through Surveillance (HELICS/IPSE) project. In this study, we analyzed the concordance between US and European definitions of HAI.

Methods

An international working group of experts from seven European countries was set up to identify differences between US and European definitions and then conduct surveillance using both sets of definitions during a three-month period (March 1^st -May 31^st, 2010). Concordance between case definitions was estimated with Cohen’s kappa statistic (κ).

Results

Differences in HAI definitions were found for bloodstream infection (BSI), pneumonia (PN), urinary tract infection (UTI) and the two key terms “intensive care unit (ICU)-acquired infection” and “mechanical ventilation”. Concordance was analyzed for these definitions and key terms with the exception of UTI. Surveillance was performed in 47 ICUs and 6,506 patients were assessed. One hundred and eighty PN and 123 BSI cases were identified. When all PN cases were considered, concordance for PN was κ = 0.99 [CI 95%: 0.98-1.00]. When PN cases were divided into subgroups, concordance was κ = 0.90 (CI 95%: 0.86-0.94) for clinically defined PN and κ = 0.72 (CI 95%: 0.63-0.82) for microbiologically defined PN. Concordance for BSI was κ = 0.73 [CI 95%: 0.66-0.80]. However, BSI cases secondary to another infection site (42% of all BSI cases) are excluded when using US definitions and concordance for BSI was κ = 1.00 when only primary BSI cases, i.e. Europe-defined BSI with ”catheter” or “unknown” origin and US-defined laboratory-confirmed BSI (LCBI), were considered.

Conclusions

Our study showed an excellent concordance between US and European definitions of PN and primary BSI. PN and primary BSI rates of countries using either US or European definitions can be compared if the points highlighted in this study are taken into account.

The Arden Syntax standard for clinical decision support: experiences and directions

Arden Syntax is a widely recognized standard for representing clinical and scientific knowledge in an executable format. It has a history that reaches back until 1989 and is currently maintained by the Health Level 7 (HL7) organization. We created a production-ready development environment, compiler, rule engine and application server for Arden Syntax. Over the course of several years, we have applied this Arden - Syntax - based CDS system in a wide variety of clinical problem domains, such as hepatitis serology interpretation, monitoring of nosocomial infections or the prediction of metastatic events in melanoma patients. We found the Arden Syntax standard to be very suitable for the practical implementation of CDS systems. Among the advantages of Arden Syntax are its status as an actively developed HL7 standard, the readability of the syntax, and various syntactic features such as flexible list handling. A major challenge we encountered was the technical integration of our CDS systems in existing, heterogeneous health information systems. To address this issue, we are currently working on incorporating the HL7 standard GELLO, which provides a standardized interface and query language for accessing data in health information systems. We hope that these planned extensions of the Arden Syntax might eventually help in realizing the vision of a global, interoperable and shared library of clinical decision support knowledge.

Early-onset ventilator-associated pneumonia incidence in intensive care units: a surveillance-based study

Background

The incidence of ventilator-associated pneumonia (VAP) within the first 48 hours of intensive care unit (ICU) stay has been poorly investigated. The objective was to estimate early-onset VAP occurrence in ICUs within 48 hours after admission.

Methods

We analyzed data from prospective surveillance between 01/01/2001 and 31/12/2009 in 11 ICUs of Lyon hospitals (France). The inclusion criteria were: first ICU admission, not hospitalized before admission, invasive mechanical ventilation during first ICU day, free of antibiotics at admission, and ICU stay ≥ 48 hours. VAP was defined according to a national protocol. Its incidence was the number of events per 1,000 invasive mechanical ventilation-days. The Poisson regression model was fitted from day 2 (D2) to D8 to incident VAP to estimate the expected VAP incidence from D0 to D1 of ICU stay.

Results

Totally, 367 (10.8%) of 3,387 patients in 45,760 patient-days developed VAP within the first 9 days. The predicted cumulative VAP incidence at D0 and D1 was 5.3 (2.6-9.8) and 8.3 (6.1-11.1), respectively. The predicted cumulative VAP incidence was 23.0 (20.8-25.3) at D8. The proportion of missed VAP within 48 hours from admission was 11% (9%-17%).

Conclusions

Our study indicates underestimation of early-onset VAP incidence in ICUs, if only VAP occurring ≥ 48 hours are considered to be hospital-acquired. Clinicians should be encouraged to develop a strategy for early detection after ICU admission.

Estimating attributable mortality due to nosocomial infections acquired in intensive care units

BACKGROUND

The strength of the association between intensive care unit (ICU)-acquired nosocomial infections (NIs) and mortality might differ according to the methodological approach taken.

OBJECTIVE

To assess the association between ICU-acquired NIs and mortality using the concept of population-attributable fraction (PAF) for patient deaths caused by ICU-acquired NIs in a large cohort of critically ill patients.

SETTING

Eleven ICUs of a French university hospital.

DESIGN

We analyzed surveillance data on ICU-acquired NIs collected prospectively during the period from 1995 through 2003. The primary outcome was mortality from ICU-acquired NI stratified by site of infection. A matched-pair, case-control study was performed. Each patient who died before ICU discharge was defined as a case patient, and each patient who survived to ICU discharge was defined as a control patient. The PAF was calculated after adjustment for confounders by use of conditional logistic regression analysis.

RESULTS

Among 8,068 ICU patients, a total of 1,725 deceased patients were successfully matched with 1,725 control patients. The adjusted PAF due to ICU-acquired NI for patients who died before ICU discharge was 14.6% (95% confidence interval [CI], 14.4%-14.8%). Stratified by the type of infection, the PAF was 6.1% (95% CI, 5.7%-6.5%) for pulmonary infection, 3.2% (95% CI, 2.8%-3.5%) for central venous catheter infection, 1.7% (95% CI, 0.9%-2.5%) for bloodstream infection, and 0.0% (95% CI, -0.4% to 0.4%) for urinary tract infection.

CONCLUSIONS

ICU-acquired NI had an important effect on mortality. However, the statistical association between ICU-acquired NI and mortality tended to be less pronounced in findings based on the PAF than in study findings based on estimates of relative risk. Therefore, the choice of methods does matter when the burden of NI needs to be assessed.

[Nosocomial infection indicators]

Nosocomial infection indicators are a reflection of healthcare quality and patient safety in hospitals. Infection indicators are calculated using surveillance programs and/or systems. Current nosocomial infection surveillance systems are based on both prevalence and incidence studies. Since 1990 the EPINE prevalence study, promoted by the Spanish Society for Preventive Medicine, Public Health and Hygiene, has developed 25 nosocomial infection indicators in hospital patients in Spain. And since 1994 the ENVIN-HELICS incidence study, promoted by the Infectious Diseases Working Group of the Spanish Society for Intensive and Critical Care Medicine and Coronary Units, has developed nine ICU-acquired infection indicators in critical patients. Participation in both surveillance systems is voluntary and has gradually increased over the years. These two control systems present the results of two different situations in the area of nosocomial infection and each complements the other; in addition, they have helped to train health professionals and to raise their awareness of nosocomial infection and patient safety. This article presents the indicators obtained in 2007 through both surveillance programs as well as their standards of reference.

The importance and future of antimicrobial surveillance studies

Surveillance studies provide important information that allows for the identification of trends in pathogen incidence and antimicrobial resistance, including identification of emerging pathogens at national and global levels. Routine surveillance is critical for creating and refining approaches to controlling antimicrobial resistance and for guiding clinician decisions regarding appropriate treatment. The traditional approach has been to monitor pathogen antimicrobial susceptibility; numerous large studies have been performed, and their designs have evolved over time. Longitudinal studies are particularly useful because important information can be obtained by comparing data over time. Another approach to surveillance, that of monitoring antimicrobial use, can help to identify trends in dosing, to prevent the development of resistance. Several studies have incorporated this approach into their methods, and both large and small studies have attempted to correlate antimicrobial use data with antimicrobial resistance data. Overall, care must be taken to coordinate programs for optimal utilization of resources, to avoid duplication of effort.

Nosocomial rotaviral gastroenteritis in paediatric departments

The authors present a retrospective analysis of community-acquired and hospital-acquired rotaviral gastroenteritis (RVGE) cases in a 5 years period 2001-2005 and prospective analysis in 2006 in the referral area in a population of 7,000 children under 5 years of age. Out of 228 patients with RVGE, nosocomial RVGE accounted for 27.75% of the cases. Children with nosocomial RVGE were in average 9.8 months younger compared to patients with community-acquired RVGE. Nosocomial cases were also characterised by the need for longer stay in intensive care, overall longer hospital stay, longer duration of the illness and by lower age of the patients. The wider implementation of vaccination in the youngest members of the population would be likely to have a significant influence on the occurrence of not only community-acquired but also hospital-acquired RVGE.

European perspective on surveillance

International comparisons yield interesting insights regarding quality of care, beyond the field of healthcare-associated infection (HAI) prevention. Therefore, the exchange of experiences of national surveillance systems should be encouraged. However, the interpretation of differences of HAI rates should be made very carefully. Differences in healthcare systems, legal and cultural aspects, as well as differences in the methods of the surveillance systems, may have an enormous influence. One of the most crucial aspects of surveillance data is their validity, therefore it would be very helpful to combine the experience of all European validation studies performed in order to develop a protocol for a meaningful and cost-effective method for performing validation studies. Meanwhile some national surveillance systems have shown their effectiveness with reductions of 24 57% for surgical site infections (SSIs) and 20 29% for HAI in ICUs. Today, mandatory public reporting is probably the most demanding problem for the national HAI surveillance systems in Europe. The exchange of experience between the European surveillance networks in this respect in particular--remains a cornerstone and will motivate further activities in the individual countries.

Estudio Nacional de Vigilancia de Infección Nosocomial en Unidades de Cuidados Intensivos. Informe evolutivo de los años 2003-2005

OBJECTIVE

Describe the national rates of acquired invasive device-related infections in the ICU during 2003, 2004 and 2005, their etiology and evolution of the multiresistance markers.

DESIGN

Prospective, observational study.

SCOPE

Intensive Care Unit or other units where critical patients are admitted.

PATIENTS

21,608 patients admitted for more than 24 hours in the participating ICUs.

MAIN VARIABLES OF INTEREST

Device related infections: pneumonias related with mechanical ventilation (N-MV), urinary infections related with urethral probe (UI-UP) and primary bacteriemias (PB) and/or those related with at risk vascular catheters (BCV).

RESULTS

In 2,279 (10.5%) patients, 3,151 infections were detected: 1,469 N-MV, 808 UI-UP and 874 PB/RVC. Incidence rates ranged from 15.5 to 17.5 N-MV per 1,000 days of mechanical ventilation, 5.0 to 6.7 UI-UP per 1,000 days of urethral probe and 4.0 to 4.7 PB/RVC per 1,000 days of vascular catheter. The predominant etiology in the N-MV was meticillin susceptible Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. The UI-UP were originated predominantly by Escherichia coli, Candida albicans and Enterococcus faecalis. A. baumannii and E. coli have increased their resistance to imipenem and ciprofloxacin or cefotaxime, respectively, in the last year controlled.

CONCLUSIONS

Elevated rates persist in all the infections controlled, without change in the etiology and increase of resistance of gram-negative bacilli.

Nosocomial infection and multidrug-resistant bacteria surveillance in intensive care units: a survey in France

OBJECTIVES

To evaluate nosocomial infection (NI) surveillance strategies in French ICUs and to identify similar patterns defining subsets within which comparisons can be made.

DESIGN

A questionnaire was sent to all French ICUs, and a random sample of nonresponders was interviewed.

PARTICIPANTS

Three hundred ninety-five responder ICUs (69%) in France.

RESULTS

In 282 ICUs (71%), a dedicated ICU staff member was responsible for infection control activities. The microbiology laboratory was usually in the hospital (90%) and computerized (94%) but issued regular hospital microbiology records in only 48% of cases. Patients receiving mechanical ventilation, central venous catheterization, and urinary catheterization were 90%, 79%, and 60%, respectively. Patients were screened for carriage of multidrug-resistant bacteria on admission and during the stay in 70% and 60% of ICUs, respectively, most often targeting MRSA. Quantitative cultures were used to diagnose ventilator-associated pneumonia (VAP) in 90% of ICUs, including distal specimens in 80% and bronchoscopy specimens in 60%. Quantitative central venous catheter (CVC)-segment cultures were used in 70% of ICUs. All CVCs were cultured routinely in 53% of the ICUs. Despite wide variations in infection control and surveillance strategies, multiple correspondence analysis identified 13 key points (4 structural variables and 9 variables concerning the diagnosis of VAP, the surveillance and diagnosis of catheter-related and urinary tract infections, and the mode of screening of MRSA carriers) that categorize the variability of French ICUs' approaches to NIs.

CONCLUSION

This study revealed profound differences in NI surveillance strategies across ICUs, indicating a need for caution when using NI surveillance data for comparisons and benchmarking.

Surgical site infection - a European perspective of incidence and economic burden

This retrospective review of reported surgical site infection (SSI) rates in Europe was undertaken to obtain an estimated scale of the problem and the associated economic burden. Preliminary literature searches revealed incomplete datasets when applying the National Nosocomial Infection Surveillance System criteria. Following an expanded literature search, studies were selected according to the number of parameters reported, from those identified as critical for accurate determination of SSI rates. Forty-eight studies were analysed. None of the reviewed studies recorded all the data necessary to enable a comparative assessment of the SSI rate to be undertaken. The estimated range from selected studies analysed varied widely from 1.5-20% - a consequence of inconsistencies in data collection methods, surveillance criteria and wide variations in the surgical procedures investigated - often unspecified. SSIs contribute greatly to the economic costs of surgical procedures - estimated range: 1.47-19.1 billion Euro dollars. The analysis suggests that the true rate of SSIs, currently unknown, is likely to have been previously under-reported. Consequently, the associated economic burden is also likely to be underestimated. A significant improvement in study design, data collection, analysis and reporting will be necessary to ensure that SSI baseline rates are more accurately assessed to enable the evaluation of future cost-effective measures.

Nosocomial infection surveillance and control activities in Spain under HELICS and NosoMed programs frame

Since the 1980s, a number of multi-center studies for the surveillance of nosocomial infections have been developed in Spain. The first of them, EPINE (study on the prevalence of nosocomial infections in Spain), was followed by two incidence-based surveillance systems: ENVIN-UCI, for intensive care units, and PREVINE, applicable to a broader range of hospital areas. These surveillance systems have made it possible for Spain to participate in two European projects, namely HELICS and NosoMed. It is expected that the European countries participating in these projects will have substantial returns in terms of better prevention and control of health care-related infections.