Aseptic insertion of central venous lines to reduce bacteraemia

Acatheter inserted with the tip in a central vein is called a central venous line (CVL). Correct insertion technique is important in prevention of central line-associated bacteraemia (CLAB). Patients in intensive care units (ICUs) are at high risk of CLAB, which increases mortality and morbidity rates, as well as costs.1 Yet, CLAB can be prevented.2,3 Since 2000, several studies have shown that educational strategies for aseptic insertion of CVLs lower rates of CLAB.4-7

In 2002, the Centers for Disease Control and Prevention (CDC) published Guidelines for the prevention of intravascular catheter-related infections.8 These and similar guidelines have been successfully applied in ICUs using collaborative methods.5,9 For example, Pronovost and colleagues showed that a regimen of hand washing, full barrier precautions, use of an alcohol-based chlorhexidine skin preparation, avoidance of femoral insertion, and early removal of the CVL resulted in an 81% reduction in the mean rate of CLAB.9

In 2007, lowering CLAB rates in patients in ICUs was included in the Patient Safety and Clinical Quality Performance Agreements between the New South Wales Department of Health and Area Health Services. The Central Line Associated Bacteraemia in NSW Intensive Care Units (CLAB ICU) Collaborative commenced in March 2007 as a “top-down – bottom-up” quality improvement project conducted by the NSW Clinical Excellence Commission and the Intensive Care Coordination and Monitoring Unit, two quality-focused organisations working in NSW with the support of the NSW Department of Health. We report here the experience of the CLAB ICU collaborative.

All 37 ICUs in NSW public hospitals were invited to participate — 10 tertiary, 12 metropolitan, 13 rural and two paediatric units. The Intensive Care Coordination and Monitoring Unit engaged with intensivists working in ICUs. The Clinical Excellence Commission provided expertise in collaborative methods, and the project team facilitated data collection and generated reports. Project governance was provided by a steering committee, with stakeholder representation. Membership and evaluation are described in the final report of the CLAB ICU collaborative.10

Data were collected from July 2007 to December 2008. All invited ICUs submitted checklists at some time during the first 12 months (July 2007 – June 2008). The total number of participating ICUs ranged from 24 in the first month to 34 during the final 6 months.

We received 11 575 checklists for CVLs inserted in ICUs: 10 890 checklists provided line type, 10 850 provided insertion site and 10 575 provided line type and insertion and removal dates. The CVLs included centrally inserted (72.6%; 7907) and peripherally inserted (13.5%; 1467) CVLs, dialysis catheters (11.9%; 1296), and other/not specified CVLs (2.0%; 220). There was no significant difference (P = 0.998) in choice of insertion site for CVLs in the run-in period and the final 6 months’ analysis period (Box 3).

Centrally inserted CVLs contributed 78.2% of all line-days over the intervention period. During the first 12 months, these CVLs remained in situ for the same period as in the final 6 months (Box 4). The median in-situ period for peripherally inserted CVLs extended by 2 days to 8 days in the final 6 months; however, peripherally inserted CVLs represented only 8.7% of the total line-days over the 18-month study period. Dialysis CVLs and other unspecified CVLs contributed 12.2% and 0.9%, respectively, of all line-days, and their median in-situ period decreased by 1 day during the final 6 months of the intervention period.

The 60% reduction in CLAB rates achieved during the intervention period — from 3.0 per 1000 line-days to 1.2 per 1000 line-days in NSW — is similar to other CLAB rate reductions published. Pronovost et al reported a reduction to a mean of 1.4 per 1000 line-days at 16–18 months.9 In 32 hospitals (69 ICUs) in the United States using similar methods, the CLAB rate was reduced by 68% to 1.36 per 1000 line-days over a 4-year period.14 Comparable results have been obtained in other US hospitals.15,16

The CLAB ICU was the first collaborative between the Clinical Excellence Commission, the Intensive Care Coordination and Monitoring Unit, the NSW Department of Health and individual ICUs. The relationship between the Commission and the Intensive Care Coordination and Monitoring Unit worked well. The relationship with individual ICUs was more challenging, as the guideline was not enforceable and the project relied on the goodwill of the ICUs. Most formed improvement teams, but there was variable engagement of key personnel. Some clinicians considered the incidence of CLAB in NSW to be low and doubted the value of the project, as Australian practice was considered to be equal to or better than the methods informing the project. Conversely, in a number of ICUs where senior clinicians gave the project clear support, there was excellent engagement with the project.

Compliance with aseptic insertion improved significantly during the intervention, indicating that the use of bundles and checklists may improve outcomes.17 The improved compliance occurred within the broader context of a CLAB awareness campaign, and the collaborative encouraged ICUs to improve all aspects of CVL insertion and management. We believe that greater awareness among ICU clinicians of the incidence and surveillance requirements of CLAB contributed to the overall reduction in CLAB rates. The rates of earlier removal of CVLs based on in-situ time and the use of femoral insertion did not change significantly between the run-in period (first 12 months) and the analysis period (final 6 months), suggesting that neither contributed to the reduced CLAB rate in our dataset, contrary to other reports.18-21

Compliance with the clinician bundle contributed to a decreased CLAB rate. Non-compliance with the clinician bundle was attributable in 94% of cases to non-compliance with the hat–mask–eyewear element. Hat wearing was identified as the contentious component of the bundle. Clinicians cited a lack of evidence as a reason to omit hats, and four ICUs elected to omit their use as standard practice for CVL insertion. There is no direct evidence linking hat wearing to CLAB. However, hats have been routinely cited as an element of clinician preparation in reports analysing reduction in CLAB rates.22-24 Compliance with both bundles was promoted in this project, and evidence suggests that hat wearing is a required step during CVL insertion, with our data indicating that the risk of CLAB increases if hats are not worn. At best this is an association, and not wearing a hat may be a surrogate for cultural or other practice issues.

There are several practical issues that may bias our results. Surveillance projects cannot be conducted with the rigour of a trial, and there were problems with identification of CLAB. This was despite dissemination of posters and concise definition notes for quick reference to ensure definition consistency between the ICUs and infection-control practitioners. Many ICUs do not have microbiological support and frequently CLAB was reported without discussion with senior ICU staff. Improved understanding of surveillance definitions, versus clinical definitions, led to reclassification in some cases.

Some ICUs resisted the requirement for clinical staff to follow up CVLs and submit checklists. There is inconsistent data collection and audit in NSW ICUs,25 with limited staff allocated to quality activities in individual ICUs; in nine referral ICUs surveyed, there were only 2.2 full-time-equivalent (FTE) physicians (three ICUs), 4.73 FTE nursing staff (four ICUs), and 0.4 FTE other staff (one ICU).26 As a data-quality initiative, two tertiary ICUs and one metropolitan ICU were asked to review data capture: all three reported data capture greater than 90%. This quality test was not completed by all sites, and at least one tertiary unit had low data capture.

From the data provided by the test sites, it is estimated that more than 15 000 CVLs are inserted in patients in NSW ICUs every year. Based on this estimate, data on fewer than 50% of CVLs inserted during the study period were captured. Most clinicians participated in the CLAB ICU intervention in addition to their normal duties. A key lesson is that for effective translation of evidence into practice, ICUs must have pre-existing integrated clinical practice improvement teams to engage front-line staff to incorporate best practice and regular audit into their daily work.

Some checklists were filled in by the proceduralist, as assistance was not always available. The hazards of self-reporting are acknowledged; however, the reporting method was the same throughout the data collection period and a reduction in CLAB rate still occurred. As this was a quality improvement initiative, not a study, these factors could not be controlled.

In summary, a guideline and checklist, backed up by a CLAB awareness campaign, reduced rates of CLAB in NSW ICUs. Strict compliance with maximal sterile barrier precautions by clinicians and full preparation of the patient were critical. This multimodal intervention was considered a success.

5 Rates (95% CI) of central line-associated bacteraemia (CLAB) per 1000 line-days, by quarters