Implementing strategies for preventing CRBSIs

In 1935, Dr Werner Forssmann inserted a catheter through a vein in his arm into the right auricle of his own heart, confirming that it was possible to access the heart using this method without invasive surgery. Since then, use of central venous catheters (CVCs) has been an integral part of patient care and is used to measure central venous pressure, administration of total parenteral nutrition (TPN), delivery of fluid and administration of drugs (for example, chemotherapy) that cannot be given safely by a peripheral catheter, and for haemodialysis.(1) It has been estimated that nearly three million CVCs are inserted annually in the US and approximately 250,000 in the UK.(2) However, insertion of CVC carries a risk of both infective complications, for example, catheter-related bloodstream infections (CRBSIs), and non-infective complications, for example, haemorrhage and pneumothorax.

CRBSIs are associated with an increase mortality risk by 25%, cost an average of US$16,550 per patient and prolong the hospital stay of patients by up to three weeks.(2)  Recent evidence suggests that, with appropriate interventions, most, if not all, episodes of CRBSIs are preventable and, as a result, these infections are being listed as a ‘never’ complication in the US by the Centers for Medicare and Medicaid Services.(3)

Several types of CVC are available, and they come in various sizes and catheter materials. They can be used in the short- (< three weeks) or long-term and can be non-tunnelled or tunnelled. Non-tunneled catheters are inserted into the subclavian, jugular or femoral vein via a peripheral venipuncture and the catheter tip is advanced until it rests in the superior vena cava of the heart. Tunneled catheters, such as Hickman and Broviac catheters, are long-term catheters that are inserted into the jugular or subclavian vein and which are then surgically tunnelled under the skin to exit the body several inches away from the vein. A Dacron cuff that sits within the skin tunnel induces an inflammatory response, which leads to growth of fibrous tissue that anchors the catheter in place and also acts as a mechanical barrier to micro-organisms.

Peripherally inserted central catheters (PICCs) can be used in the short-term. The Groshong can be used either tunneled or non-tunneled and is inserted into a vein in the arm (usually the basilic, brachial, or cephalic vein) rather than a vein in the neck or chest and their use is recommended when the duration of intravenous therapy is likely to exceed six days.(1)

Implantable devices, such as Port-A-Cath^®, are catheters placed surgically under the skin in the subcutaneous pocket of the upper chest wall. They are useful for long-term vascular access and carry the lowest risk of infection because they are not external to the body; a Huber needle is used to puncture the skin and the septum over the reservoir to administer therapy.

Risk factors for acquiring CRBSIs can be classified into patient factors (for example, age, gender and underlying diseases), which are non-modifiable. However, most factors are extrinsic and are potentially modifiable, for example, prolonged hospitalisation before CVC insertion, multiple and/or multi-lumen CVCs, administration of TPN, use of femoral or internal jugular access sites, heavy bioburden at the insertion site, lack of maximal sterile barriers and break in aseptic technique during insertion and maintenance.

CVCs can become contaminated with micro-organisms via two major routes:

Extraluminal contamination can occur from the patient’s skin organisms at the insertion site. The bacteria can migrate along the surface of the catheter into the cutaneous tract surrounding the catheter, resulting in colonisation at the catheter tip. This is a common source of infection for short-term (≤ ten days), non-tunneled CVCs. Because a CVC is a foreign body that produces a reaction in the host consisting of a film of fibrinous material (biofilm) on the inner and outer surfaces of the catheter. This biofilm might become colonised by micro-organisms and will be protected from host defence mechanisms and makes treatment with antibiotics ineffective. Therefore, once the CVC-related infection is suspected or confirmed, removal of the catheter is necessary.

Intraluminal contamination most commonly occurs from direct contamination of the catheter or at any point along the fluid pathway when the IV system is manipulated, for example, when a healthcare worker’s contaminated hand comes into contact with IV solution, connection sites, access hubs, needleless connectors or tubing junctions, or is contaminated with the patient’s own body fluids or skin. This route of infection is more common especially with CVC that are of longer duration (>ten days).

Current strategies to prevent CRBSIs are based on the implementation of a ‘care bundle’ developed by the Institute of Health Improvement (IHI)(4) and adopted and modified by the UK Department of Health(5) and  summarised in Table 1.

Polyurethane and silicone catheters have a lower risk of complication than other types. Single-lumen catheters should be used unless multiple ports are essential. If TPN is being administered, a dedicated single-lumen CVC or dedicated lumen on a multi-lumen CVC should be used.

Antimicrobial/antiseptic-impregnated catheters (for example, chlorhexidine–silver sulphadiazine and minocycline–rifampin) have a lower rate of colonisation than standard CVCs. However, these catheters should not be used routinely and should only be considered in adult patients who require catheterisation for longer than five days when there is still a high rate of catheter-related sepsis, despite full adherence to maximum infection control precautions both during insertion and maintenance.

It is essential that the person inserting the CVC have appropriate training and expertise. Choice of insertion site and technique with the lowest risk of complications should be selected. For example, a catheter should not be inserted into an area of inflammation or infection, and subclavian rather than the jugular or femoral sites should be selected unless medically contraindicated. The risk of infection is highest in femoral sites because of the very high density of skin microflora. Once the CVC has been inserted, it must be secured with sutures or clips to prevent catheter movement, dislodgement and sepsis.

Adherence to aseptic technique, both during catheter insertion and maintenance, is essential. If possible, dedicated IV teams should be appointed. It is essential that admixtures and the preparation of all TPN solutions be carried out using strict aseptic technique in the pharmacy. If this facility is not available, then a laminar-flow hood/cabinet should be used. All access points (for example, hubs, connectors, or injection ports) must be disinfected using 70% isopropyl alcohol before use and hand hygiene must be performed  before this procedure.

Skin must be disinfected using a single-use sterile antiseptic solution containing 2% chlorhexidine gluconate in 70% isopropyl alcohol and the site allowed to dry before CVC insertion. Use of any antiseptics from the multi-use container must be avoided. Chlorhexidine gluconate should not be used in patients aged less than two months. Alternately, an iodophor or an alcoholic povidone–iodine solution should be used for patients with a history of chlorhexidine sensitivity or if chlorhexidine gluconate is not available in the country. If povidone–iodine is used, it should remain on the skin for at least two minutes until it is dry.

Sterile dressings should be used to cover the catheter site and should be replaced when the dressing becomes damp, loosened or soiled, or when inspection of the site is necessary. For tunnelled or implanted catheters, the dressing should be replaced no more than once a week, until the insertion site is healed. Use of semipermeable adhesive dressings is preferred because they have the advantage of allowing inspection of the site without the removal of the dressing; this dressing should be changed every seven days unless clinically indicated. Gauze dressing is used if the site is bleeding or oozing and this dressing should be replaced every two days or sonner if damp, loosened, or soiled.

Use of a sustained-release chlorhexidine gluconate-impregnated sponge has been shown to substantially reduce CVC infections.(6) Its use should be considered, provided that all other basic infection control measures have been implemented.

Routine use of antibiotic(s) (systematic, topical or intranasal ointment) before CVC insertion is not recommended to prevent CRBSIs. Topical antimicrobial ointments should not  be used as a part of routine CVC site care because of their potential to promote fungal infections and antimicrobial resistance.

CVCs should not routinely be replaced solely for the purpose of reducing infection. Replacement is necessary if catheter-related sepsis is suspected. Any catheter inserted when adherence to proper asepsis is not ensured (for example, those inserted in an emergency) should be re-sited at the earliest opportunity, preferably within 48h.

Due to the complexity of various factors, it is not possible to achieve a 100% reduction in all healthcare-associated infections (HCAIs) but it has been estimated that up to a 70% reduction in HCAIs can be achieved by using various interventions.(7) Effective implementation of these interventions in the intensive care units (ICUs) in Michigan, US, has virtually eliminated CRBSIs. The ‘Matching Michigan’ programme has been successfully implemented to reduce CVC bloodstream infections in ICUs in England.(8) Pronovost and colleagues have demonstrated that this programme could be successfully implemented on a large scale and sustained on a long-term basis.(9,10)

In summary, the key elements of reducing/eliminating CRBSI  include:

(i) continuous education and training;  (ii) asking the clinical team to review daily the continued need for a CVC; (iii) empowering the bedside nurse to stop a CVC insertion if guidelines were not followed correctly; (iv) having a CVC insertion trolley to ensure all elements of insertion are kept in one common location; (v) CVC checklist performed by the bedside nurse; and (vi) adherence to strict asepsis technique both during insertion and daily maintenance.