CVC-related infections are potentially modifiable, thus highlighting the importance of implementing evidence-based infection prevention and control interventions that may contribute to limiting the occurrence of such infections. There is no published literature on the practices underpinning VA management and care in haemodialysis settings in Ireland.
As outlined in chapter 2 (section 2.5), prevention of CVC-related infections is multifaceted, incorporating the education of healthcare personnel about guidelines to prevent catheter-related infections and the implementation of evidence-based interventions when caring for the CVC exit site and catheter hubs, both high risk areas for contamination and colonisation. A variety of interventions are used to prevent haemodialysis CVC-related infections suggesting confusion regarding best practice in this area. Examples of these interventions include the use of various prophylactic antibiotics prior to catheter insertion, antimicrobial-catheter locking solutions, antimicrobial- impregnated catheters, antiseptic solutions to clean the exit site, topical antimicrobial ointments and dressings to cover the exit site (Sesso et al. 1998, Johnson et al. 2002, Chatzinikolaou et al. 2003, Le Corre et al. 2003, McIntyre
et al. 2004, Percival et al. 2005). International guidelines offer conflicting advice on interventions preventing CVC-related infections in haemodialysis patients, thereby compounding the confusion for clinicians (CARI 2000, CDC 2002, ERA-EDTA 2002, Jindal et al. 2006, NKF K/DOQI 2006b, SARI 2009). There is a lack of clarity on the interventions used in dialysis units in Ireland due to the lack of published paper/reports on VA and infection prevention and control practices in these units.
Haemodialysis patients with CVCs are at increased risk of HCAI that impact on patient safety and lead to an increased incidence of death due to infection and costly lengthy periods of hospitalisations. As discussed earlier in this chapter, such infections are often associated with economically and clinically significant complications. Consequently, it is incumbent on members of the renal team (including haemodialysis nurses) to identify and implement evidence-based infection prevention and control interventions that will limit the
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impact of such infections on the physical and mental wellbeing of patients and the costs associated with their treatment. As the number of haemodialysis patients using a CVC continues to grow and, with it, the need for a robust evidence-base for practice, a systematic review of the worldwide evidence was necessary in order to summarise the evidence available on interventions for preventing CVC-related infections in this patient population. This systematic review, conducted using the Cochrane Renal Group methodology framework, is presented in Chapter 4.
3.7 Summary
ESKD is a global health issue that is managed either conservatively or through the provision of some form of renal replacement therapy, the most common being haemodialysis. Incidence and prevalence of this disease continues to increase across the well-resourced parts of the world, with a marked increase in patients aged over 75 years.
Haemodialysis VA can be problematic for patients with ESKD, with a higher incidence of CVCs than AVFs. Despite being the less preferred VA choice, the use of CVCs is also rising among the prevalent patient population. The most widely used catheter for chronic haemodialysis patients is a dual-lumen tunnelled permanent cuffed CVC.
Haemodialysis patients with CVCs are at increased risk of HCAI when compared to non ESKD patients. CVC-related infections include bloodstream infections (bacteraemia), exit site and tunnel infections. By far the most significant infection when considering patient safety is a bloodstream infection. Patients with a CVC have a higher risk of mortality (including infection-related mortality), higher incidence of VA-related infection (in particular, bloodstream infections) and higher rates of hospitalisation and healthcare costs than patients dialysed via an AVF. CVC-related infections also have a negative impact on catheter survival.
Patients with CVCs have a raised risk of infection due to the nature of their disease, which decreases their immune response to infection. Other factors include co-morbidities such as diabetes mellitus and malignancy, immunosuppressive therapy, low serum albumin level, duration of catheter, history of previous tunnelled catheters and previous catheter infection
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especially bloodstream infections. Another risk factor for CVC-related infection relates to the technique used in catheter placement. Poor techniques can result in early manifestation of CVC bloodstream infections.
Catheter insertion involves breaching the body’s natural defence, exposing the patient to the risk of flora migrating from their own skin, through the catheter exit site and onto the exterior surface of the catheter leading to colonisation of the catheter tip. Direct contamination of the catheter hubs occurs as a result of multiple manipulation of the catheter during dialysis, whereby the catheter hubs may be exposed to the patient’s own flora or contaminated from healthcare workers’ hands. These potential portals of entry for infection reinforce the need for strict aseptic technique when manipulating the catheter during dialysis. This review of the literature indicates that exit site infections were positively associated with the type of CVC dressing and antiseptic cleansing solution used in the maintenance of the catheter; this underlines the importance of using effective interventions that prevent exit site and catheter hub contamination.
National standards advocate the use of evidence-based interventions for the prevention and control of catheter associated HCAI (Health Information and Quality Authority 2009). Furthermore, national and international bodies offer guidance on a breadth of interventions for the prevention of catheter-related infections; however, there lacks general consensus on what is best practice in a number of areas of practice (CARI 2000, CDC 2002, ERA-EDTA 2002, Jindal et al. 2006, NKF K/DOQI 2006b, SARI 2009). This chapter highlights the need for a systematic review on the world-wide evidence on the effects of interventions to prevent infectious complications in haemodialysis patients.
3.8 Conclusion
This chapter shows that preventing CVC-related infections is a multifaceted task, making it imperative that the protocol for the randomised trial that is part of this PhD research project incorporates the provision of routine care that includes key components of an effective preventive strategy, such as education of healthcare staff, hand hygiene, and aseptic technique. However, there is a dearth of published literature on the practices underpinning VA practices and infection prevention and control practices in Irish haemodialysis settings. Therefore, in order to place the findings of this study in the context of
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these settings, a descriptive survey of routine VA practices was undertaken (Chapter 6).
The chapter also highlights issues that have implications for the design of this randomised trial. Age, sex, primary renal diagnosis and risk factors for CVC infections warrant inclusion in the baseline data collection form. As patients are at risk of post insertion-related catheter infection, this has implications for the trial exclusion criteria. The key outcomes identified in this review of the literature will inform the outcomes of this study. These include bloodstream infections, exit site infections, mortality, VA-related mortality, hospitalisation, VA-related hospitalisation, CVC survival, causative organisms and prevalence of vascular access.
Studies discussed in this chapter, including those from Ireland, which investigated CVC-related infections, used various case definitions to classify and diagnose CVC-related infections. This limits their comparability. From a research activity perspective the most robust case definitions for the diagnosis of CVC-related infection are CRBSI and CABSI. The most precise classification system for the diagnosis of CVC-related infections is the CRBSI clinical case definition, proposed by the IDSA. This definition does have limitations, particularly for use in the haemodialysis patient population. It requires specific tests that may not routinely be available in hospital laboratories aligned to the outpatient haemodialysis sites for this randomised trial or tests requiring specific blood cultures that may not be obtainable from haemodialysis patients. Culturing the tip of the CVC is one of the diagnostic tests advocated in the definition; but this is not always feasible due to a reluctance to remove the patient’s only form of vascular access for haemodialysis. Given these limitations, it would be prudent to include the CDC/NHSN CABSI surveillance case definition for the diagnosis of bloodstream infections in this study also. Culturing the catheter tip is not a requirement and any clinical uncertainties relating to common skin contaminants and secondary bloodstream infections are removed. A third case definition that warrants inclusion is the outpatient haemodialysis specific CDC/NHSN surveillance dialysis event protocol case definitions. Although this protocol may not be sufficiently robust for research activity, it is used in outpatient haemodialysis settings in America and Europe and will allow comparability of trial findings to the international literature. The dialysis event
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protocol definition for local access infection will be used to diagnose exit site infections that occur in trial participants.
CABSI and CRBSI case definitions are normally associated with line days for denominator data, but the collection of such data is not suited for an outpatient haemodialysis setting. An alternative approach that best suits the use of such rigorous case definitions, within a robust randomised trial such as this PhD outpatient haemodialysis study is the reporting of CABSI, CRBSI, local access infections and dialysis events per 100 patient-months. This requires the collection of denominator data (number of CVCs) on the first two working days of each month.
Finally, given the ever increasing use of CVCs in the haemodialysis patient population and the associated risk of infection, it is imperative that effective interventions are used to prevent CVC-related infections. However, various interventions are used in the care and maintenance of haemodialysis CVCs, suggesting inconsistent implementation of best practice guidelines and/or uncertainty regarding best practice in this area. This lack of clarity highlights the need to conduct a systematic review of the world-wide evidence on interventions for the prevention of infectious complications in haemodialysis patients with CVCs. This systematic review is presented in the following chapter and provides evidence that underpins the direction and focus of this randomised trial.
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SECTION 2
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