Summary
When planning parenteral nutrition (PN), the proper choice, insertion, and nursing of the venous access are of paramount importance. In hospitalized patients, PN can be delivered through short-term, non-tunneled central venous catheters, through
peripherally inserted central catheters (PICC), or – for limited period of time and with limitation in the osmolarity and composition of the solution – through
peripheral venous access devices (short cannulas and midline catheters). Home PN usually requires PICCs or – if planned for an
extended or unlimited time – long-term venous access devices (tunneled catheters and totally implantable ports).
The most appropriate site for central venous access will take into account many factors, including the patient's conditions and the relative risk of infective and non-infective complications associated with each site. Ultrasound-guided venepuncture is strongly recommended for access to all central veins. For parenteral nutrition, the ideal position of the catheter tip is between the lower third of the superior cava vein and the upper third of the right atrium; this should preferably be checked during the procedure.
Catheter-related bloodstream infection is an important and still too common complication of parenteral nutrition. The risk of infection can be reduced by adopting cost-effective, evidence-based interventions such as proper education and specific training of the staff, an adequate hand washing policy, proper choices of the type of device and the site of insertion, use of maximal barrier protection during insertion, use of chlorhexidine as antiseptic prior to insertion and for disinfecting the exit site thereafter, appropriate policies for the dressing of the exit site, routine changes of administration sets, and removal of central lines as soon as they are no longer necessary.
Most non-infective complications of central venous access devices can also be prevented by appropriate, standardized protocols for line insertion and maintenance. These too depend on appropriate choice of device, skilled implantation and correct positioning of the catheter, adequate stabilization of the device (preferably avoiding stitches), and the use of infusion pumps, as well as adequate policies for flushing and locking lines which are not in use.Summary of statements: Central Venous Catheters
SubjectRecommendationsGradeNumber
Choice of route for intravenous nutritionCentral venous access (i.e., venous access which allows delivery of nutrients directly into the superior vena cava or the right atrium) is needed in most patients who are candidates for parenteral nutrition (PN).C1
In some situations however PN may be safely delivered by peripheral access (short cannula or midline catheter), as when using a solution with low osmolarity, with a substantial proportion of the non-protein calories given as lipid.
It is recommended that peripheral PN (given through a short peripheral cannula or through a midline catheter) should be used only for a limited period of time, and only when using nutrient solutions whose osmolarity does not exceed 850 mOsm/L.
Home PN should not normally be given via short cannulas as these carry a high risk of dislocation and complications.
Peripheral PN, whether through short cannulas or midline catheters, demands careful surveillance for thrombophlebitis.
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Choice of PN catheter deviceShort-term: many non-tunneled central venous catheters (CVCs), as well as peripherally inserted central catheters (PICCs), and peripheral catheters are suitable for in-patient PN.B2
Medium-term: PICCs, Hohn catheters, and tunneled catheters and ports are appropriate. Non-tunneled central venous catheters are discouraged in HPN, because of high rates of infection, obstruction, dislocation, and venous thrombosis.
Prolonged use and HPN (>3 months) usually require a long-term device. There is a choice between tunneled catheters and totally implantable devices. In those requiring frequent (daily) access a tunneled device is generally preferable.
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Choice of vein for PNThe choice of vein is affected by several factors including venepuncture technique, the risk of related mechanical complications, the feasibility of appropriate nursing of the catheter site, and the risk of thrombotic and infective complications.C3
The use of the femoral vein for PN is relatively contraindicated, since this is associated with a high risk of contamination at the exit site in the groin, and a high risk of venous thrombosis.
High approaches to the internal jugular vein (either anterior or posterior to the sternoclavicular muscle) are not recommended, since the exit site is difficult to nurse, and there is thus a high risk of catheter contamination and catheter-related infection.
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Insertion of CVCsThere is compelling evidence that ultrasound-guided venepuncture (by real-time ultrasonography) is associated with a lower incidence of complications and a higher rate of success than ‘blind’ venepuncture. Ultrasound support is therefore strongly recommended for all CVC insertions. Placement by surgical cutdown is not recommended, in terms of cost-effectiveness and risk of infection.A4
In placement of PICCs, percutaneous cannulation of the basilic vein or the brachial vein in the midarm, utilizing ultrasound guidance and the micro-introducer technique, is the preferred optionB4
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Position of CVC tipHigh osmolarity PN requires central venous access and should be delivered through a catheter whose tip is in the lower third of the superior vena cava, at the atrio-caval junction, or in the upper portion of the right atrium (Grade A). The position of the tip should preferably be checked during the procedure, especially when an infraclavicular approach to the subclavian vein has been used.C, B5
Postoperative X-ray is mandatory (a) when the position of the tip has not been checked during the procedure, and/or (b) when the device has been placed using blind subclavian approach or other techniques which carry the risk of pleuropulmonary damage.
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Choice of material for CVCThere is limited evidence to suggest that the catheter material is important in the etiology of catheter-related sepsis. Teflon, silicone and polyurethane (PUR) have been associated with fewer infections than polyvinyl chloride or polyethylene. Currently all available CVCs are made either of PUR (short-term and medium-term) or silicone (medium-term and long-term); no specific recommendation for clinical practice is made.B6
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Reducing the risk of catheter-related infectionEvidence indicates that the risk of catheter-related infection is reduced by:
• Using tunneled and implanted catheters (value only confirmed in long-term use)
• Using antimicrobial coated catheters (value only shown in short-term use)
• Using single-lumen catheters
• Using peripheral access (PICC) when possible
• Appropriate choice of the insertion site
• Ultrasound-guided venepuncture
• Use of maximal barrier precautions during insertion
• Proper education and specific training of the staff
• An adequate policy of hand washing
• Use of 2 % chlorhexidine as skin antiseptic
• Appropriate dressing of the exit site
• Disinfection of hubs, stopcocks and needle-free connectors
• Regular change of administration setsSome interventions are not effective in reducing the risk of infection, and should not be adopted for this purpose; these include:• in-line filters
• routine replacement of central lines on a scheduled basis
• antibiotic prophylaxis
• the use of heparin
B6
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Diagnosis of catheter-related sepsisDiagnosis of CRBSI is best achieved (a) by quantitative or semi-quantitative culture of the catheter (when the CVC is removed or exchanged over a guide wire), or (b) by paired quantitative blood cultures or paired qualitative blood cultures from a peripheral vein and from the catheter, with continuously monitoring of the differential time to positivity (if the catheter is left in place).A7
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Treatment of catheter-related sepsis (short-term lines)A short-term central line should be removed in the case of (a) evident signs of local infection at the exit site, (b) clinical signs of sepsis, (c) positive culture of the catheter exchanged over guide wire, or (d) positive paired blood cultures (from peripheral blood and blood drawn from the catheter). Appropriate antibiotic therapy should be continued after catheter removal.B8
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Treatment of catheter-related sepsis (long-term lines)Removal of the long-term venous access is required in case of (a) tunnel infection or port abscess, (b) clinical signs of septic shock, (c) paired blood cultures positive for fungi or highly virulent bacteria, and/or (d) complicated infection (e.g., evidence of endocarditis, septic thrombosis, or other metastatic infections). In other cases, an attempt to save the device may be tried, using the antibiotic lock technique.B9
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Routine care of central cathetersMost central venous access devices for PN can be safely flushed and locked with saline solution when not in use.C10
Heparinized solutions may be used as a lock (after flushing with saline), when recommended by the manufacturer, in the case of implanted ports or opened-ended catheter lumens which are scheduled to remain closed for more than 8 h.
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Prevention of line occlusionIntraluminal obstruction of the central venous access can be prevented by appropriate nursing protocols in maintenance of the line, including the use of nutritional pumps.C11
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Prevention of catheter-related central venous thrombosisThrombosis is avoided by the use of insertion techniques designed to limit damage to the vein, including• Ultrasound guidance at insertion
• choice of a catheter with the smallest caliber compatible with the infusion therapy needed
• position of the tip of the catheter at or near to the atrio-caval junction
Prophylaxis with a daily subcutaneous dose of low molecular weight heparin is effective only in patients at high risk for thrombosis.B12
