Indwelling intravascular access devices (catheters) provide a route for:
- administering fluids, blood products, nutrients and intravenous medications;
- monitoring haemodynamic function;
- maintaining emergency vascular access; and
- obtaining blood specimens.
Intravascular devices (IVDs) are catheters that are usually inserted into peripheral veins (e.g. small veins in the arms). Peripheral arterial devices are also used for some patients.
Central venous catheters are inserted into larger veins within the chest and abdomen. They generally remain in place for longer than peripheral vein catheters.
Some central venous catheters are inserted through a peripheral vein site (peripherally inserted central catheters [PICC or PIC lines]). They can be used for a prolonged period of time (e.g. for long chemotherapy regimens, extended antibiotic therapy, or total parenteral nutrition).
IVD insertion is the most commonly performed invasive healthcare procedure with approximately 14 million IVDs used in Australia each year (Collignon 1994; ABS 2008).
What are the risks?
IVDs provide potential routes for infectious agents to cause local infection or to enter the bloodstream. As a result, despite their important role in diagnostic and therapeutic care, IVDs are a potential source of HAIs, the most severe form being bloodstream infections (BSI) associated with the insertion and maintenance of central venous access devices. There are about 5,000 cases of IVD-related BSI a year in Australia (Collignon 1994; ABS 2008). IVD-related BSIs are associated with significant mortality, worsen the severity of the patient’s underlying ill health, prolong the period of hospitalisation and increase the cost of care.
There is risk of infection when the device is inserted and while it remains in situ. The risks inherent in insertion of IVDs include bypassing the skin, which is such an important barrier against microorganisms gaining entry to sterile sites such as the bloodstream, and leaving a foreign body in the patient for several days or longer which is likely to become colonised by microorganisms.
Figure B4.1: Potential sources for indwelling device contamination
- Skin organisms: Colonisation of the external surfaces of the IVD by microorganisms from the patient’s skin around the insertion site. This can occur through contamination of the catheter tip at the time of insertion or migration of skin organisms at the insertion site into the cutaneous catheter tract after insertion.
- Contamination of the catheter hub with distal spread of the organisms down the intraluminal surface. This is largely thought to occur during handling of the connections at catheter junctions.
- Occasionally, the catheter might become haematogenously seeded from another focus of infection.
- Contamination of the fluid infusate occurs on rare occasions.
Source: Illustration used with permission from Professor Dennis Maki.
Table B4.6: Risk factors for IVD-related BSI
- Prolonged hospitalisation before the IVD is inserted
- Prolonged placement of the device
- Heavy microbial colonisation of the insertion site that contaminate the catheter during insertion and migrate along the cutaneous catheter track
- Heavy microbial colonisation of the cannula/catheter hub, usually secondary to contamination from healthcare workers’ hands during care interventions such as injections
- Antibiotic use during catheterisation.
The microorganisms that colonise catheter hubs and the skin adjacent to the insertion site are the source of most IVD-related BSI. Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, are the most frequently implicated microorganisms. Other microorganisms commonly involved include Staphylococcus aureus, Candida species and enterococci.
Prolonged duration of peripheral IV catheters greatly increases the risk of infection — while only 1–2% of peripheral catheters remain in place for longer than 2 days, these are associated with 90% of IVD-related BSIs (Collignon P, unpublished study).
Minimising the risk from intravascular access devices
To minimise the risk to patients, IVDs should only be used when absolutely necessary. They must be removed as soon as they are no longer needed or alternative means are available to deliver appropriate care (e.g. oral drugs instead of IV delivery). Prevention of catheter-related BSI requires a set of infection control measures (see care bundles box below).
Decision-making about IVDs
Decision-making about IVDs should involve the consideration of:
- whether oral administration is possible;
- which device poses the lowest risk to the patient;
- the reduced risk of sepsis associated with permanent access devices (e.g. fistula) if long-term administration is required (e.g for heamodialysis); and
- the importance of removing the IVD when it is no longer needed or a safer alternative can be used.
If a central venous access catheter is necessary, it must be inserted under maximal barrier precautions (i.e. similar to surgical procedures). The femoral site of insertion should be avoided (Hamilton and Foxcraft 2008).
Table B4.7: Central venous catheter decision tree for adults
- Assess the physical status and vascular access history of the patient
- Base a decision on the type and duration of therapy required
- Carefully consider the need for central v peripheral vascular access
- Do not lose sight of the patient as the focus for your decision
- Ensure clear documentation of all key events in the clinical record
Source: The Canberra Hospital.
Evidence supporting practice20
- Alcohols are the most effective and most rapid-acting skin antiseptics. Alcohol-based preparations that have 70% isopropyl alcohol v/v and at least 0.5% chlorhexidine are recommended for procedures penetrating skin (including subcutaneous infusions). Typically available solutions range from 0.5% to 4% and there is strong evidence (Grade A) that skin preparations with at least 0.5% chlorhexidine-gluconate solution reduce intravascular device colonisation.
Insertion of IVDs
- There is Grade B evidence that maximum barrier precautions (inserter wears mask, cap, sterile gown, sterile gloves, uses large sterile drape; assistant wears cap and mask) reduce immediate post-insertion skin colonisation in short-term central venous devices.
Maximum barrier precautions are not necessary for insertion of short peripheral venous or arterial devices; device colonisation or IVD-related BSI was not reduced compared to when standard good practice care was used (inserter wears sterile gloves and uses sterile equipment).
- The safe maintenance of an IVD includes good practice in caring for the patient’s catheter hub and connection port to avoid contamination by staff hands, the use of an appropriate site dressing regimen, and using flush solutions to maintain the patency of the line.
For patients who require long-term venous access (e.g. renal dialysis), permanent access devices (e.g. fistulas) reduce the risk of infection compared to other forms of IV access.
Choice of dressings
- There is strong evidence (Grade B) that the use of chlorhexidine-impregnated (CHG) sponges at the catheter insertion site significantly reduces IVD-related bloodstream infection and device colonisation rates compared to other types of dressings for peripheral arterial devices, short-term and long-term central venous devices. The safety of these sponges has not been established in low birth-weight neonates who may be at risk of skin or systemic toxicity.
- There is insufficient evidence to determine a significant difference in the use of sterile gauze over other dressings (tape, transparent polyurethane, or highly moisture permeable transparent dressings) to reduce phlebitis incidence in peripheral IVDs and tunnelled central venous catheters (used for haemodialysis and oncology); or in preventing infectious complications in short and long-term central venous devices (including those used for haemodialysis).
- Patient preference, clinician preference and costs are currently acceptable factors when choosing between sterile gauze and transparent polyurethane dressings.
- There is Grade B evidence that the use of an antimicrobial or antibiotic ointment (calcium mupirocin, or Polysporin) on long-term tunnelled central venous devices used for haemodialysis access, significantly reduces IVD-associated BSIs and exit site infections.
- Povidone iodine antiseptic ointment or bacitracin/neomycin/polymyxin B ointment should only be used at the hemodialysis catheter exit site after catheter insertion and at the end of each dialysis session if this ointment does not interact with the material of the hemodialysis catheter (as per manufacturer's recommendations)(O’Grady et al 2002).
- The evidence (Grade C) supports daily examination of short-term vascular catheter dressings to assess whether they require changing. Dressing change is indicated where the dressing is loose or soiled.
- There is strong evidence that scheduled seven-day replacement of transparent dressings for short-term central venous and peripheral arterial devices (with or without CHG sponges) is equally as effective in preventing device colonisation and IVD-related BSI as scheduled three-day replacement.
- There is some evidence that eight-day replacement of transparent dressings for tunnelled central venous devices significantly reduces skin toxicity, and does not change IVD-related BSI rates, compared with four‑day replacement.
- Evidence regarding paediatric central venous device dressings (Grade C) suggests that these should be changed at least every seven days.
- In adults, most studies use phlebitis (which may have a chemical or traumatic basis) as an endpoint and find little or no benefits for routinely changing short peripheral vein catheters Evidence suggests that bacteraemia is disproportionately associated with catheters in place for more than 2 days. Removing a catheter eliminates the risk for associated sepsis.
- There is some evidence that routine replacement of short-term central venous devices compared with replacement on clinical indication has no effect on IVD-related BSI rates per adult patient.
Replacement of administration sets
- There is strong evidence (Grade B) that administration sets that do not contain lipids, blood or blood products may be left in place for intervals of up to 4 days.
Before discharge from hospital, patients and their carers should be provided with education, supported by written instructions, on the management and care of an indwelling device, including the prevention of infection.
Table B4.8: Summary of processes for insertion, maintenance and replacement of intravascular access devices
Replacement of administration sets
Figure B4.2: PPE and maximal barrier precautions for IVD insertion
IVD care bundles
There are numerous care bundles in use on the management of central and peripheral vascular devices. Information on bundles and their implementation is discussed in Section B4.1.3.
Before implementing a care bundle it is important to identify current practice in the particular area. Gaps in service provision need to be identified, analysed and systematically addressed through the implementation of the bundle.
Examples available bundles include:
- Based also on evidence identified through Richard C, Ray-Barruel G (2009). Systematic literature review