Chapter 17: Vascular access devices: insertion and management
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Evidence‐based approaches
Rationale
Indications
VADs are used:
- to obtain venous and arterial blood samples
- to administer fluids, nutrition, medication or blood products
- to monitor central venous pressure and arterial pressure.
Contraindications
There are no specific contraindications for inserting a VAD but there may be contraindications for location of the device and the type of medication that can be administered (very few can be administered via an artery).
Principles of care
Regardless of the type of VAD used, the principles of care for the device remain the same:
- to prevent infection
- to maintain a ‘closed’ intravenous system with minimal connections to reduce the risk of contamination
- to prevent damage to the device and associated intravenous equipment
- to maintain a patent and correctly positioned device.
Each of these principles will be discussed generally and then in more detail under each type of access device.
Methods of preventing infection at the insertion site
Aseptic technique and compliance with recommendations for equipment and dressing changes are essential if microbial contamination is to be prevented (Gorski et al. [181], Loveday et al. [278], O'Grady et al. [362], RCN [381]). Whenever the insertion site is exposed or the intravenous system is broken, standard aseptic non‐touch technique (ANTT) should be practised. ANTT is basic in nature and clearly defined, focusing on the essentials of all intravenous therapy regardless of the intravenous device (Rowley et al. [389]) and it is now the de facto standard aseptic technique in the UK (Rowley and Clare [388]), used for all techniques relating to VADs regardless of whether they are peripherally or centrally inserted (Loveday et al. [278], Rowley et al. [389]). Where blood or body fluids may be present, gloves should be worn to comply with safe practice guidelines (Rowley [387]). It is not necessary to wear sterile gloves when accessing a central venous access device (CVAD); clean gloves are adequate (Hemsworth et al. [209]). The use of well‐fitting gloves is key in ANTT: they should be neither too small nor too large as they may otherwise impede manual dexterity (RCN [381]) (see also Chapter c04: Infection prevention and control).
Cleaning solutions
Most transient flora can be removed from the skin with soap and water using mechanical friction. It is also important to remove dirt, which renders antiseptic solutions less effective as they cannot penetrate surface dirt (McGoldrick [305]). Use of a chlorhexidine bath or shower prior to insertion of a central venous catheter has been shown to reduce infection (Lopez [275], Montecalvo et al. [322]). 2% chlorhexidine in 70% alcohol has been shown to be the most effective agent for skin cleaning around the VAD insertion site prior to insertion and between dressing changes (Cobbett and LeBlanc [80], DH [117], Kim and Lam [244], Maki et al. [293], Nishihara et al. [355], O'Grady et al. [362], Soothill et al. [422], Timsit et al. [440]). The 70% alcohol acts by denaturing protein and so has excellent properties for destruction of gram‐positive and gram‐negative bacteria, as well as being active against fungi and viral organisms. Alcohol concentrations between 70% and 92% provide the most rapid and greatest reduction in microbial counts on skin but do not have any residual activity (Larson [262]). This is where chlorhexidine in alcohol has an advantage over alcohol used alone (Loveday et al. [278], Nishihara et al. [355]). Therefore, chlorhexidine (>0.5% concentration) in 70% alcohol is recommended (Moureau [328]) as alcohol has an immediate effect and dries quickly, but chlorhexidine has ongoing antimicrobial action for 7–10 days; when used together, they also kill a wide variety of micro‐organisms (Rickard et al. [383]). It is important to be aware of patient sensitivity to chlorhexidine gluconate (Loveday et al. [278], MHRA [314]), both in cleaning solutions and within coatings of CVADs. For patients with sensitivities to chlorhexidine, consider tincture of iodine, povidone‐iodine or 70% alcohol (Gorski et al. [181]). In patients with very delicate skin, cleaning with 70% alcohol followed by sterile saline and 0.5% chlorhexidine in aqueous solution is recommended in practice (Rickard et al. [383]).
Solutions should be applied with friction in back‐and‐forth strokes for at least 30 seconds and allowed to air dry for 30–60 seconds (DH [117], Gorski et al. [181], McGoldrick [305], O'Grady et al. [362], Scales [401]). It has been found that 1 minute of application with alcohol is as effective as 12 minutes of scrubbing and reduces bacterial counts by 75%. However, a quick wipe fails to reduce bacterial counts prior to peripheral cannulation (Gorski et al. [181], Weinstein and Hagle [465]). Allowing any cleaning solution to dry is vital in order for disinfection to be completed and, in the case of alcohol, which is a plasticizer, it ensures that plastic equipment will not ‘glue together’ (Dougherty [123]). Dressings placed on moist skin are the true cause of many so‐called ‘dressing allergies’, where skin becomes red, painful and/or itchy (Rickard et al. [383]).
Inspection of insertion site and cleaning of equipment
Cleaning solutions should be used not only on insertion sites but also to clean junctions, connections and so on. It is recommended that injection caps should be cleaned vigorously with appropriate cleaning agents such as 2% chlorhexidine in alcohol (Brown et al. [53], DH [117], Loveday et al. [278], NICE [351], Wright et al. [476]). The optimal frequency for cleaning the insertion site is debatable; peripheral sites are rarely cleaned once the device is sited because the device is in situ for such a short period of time. However, central venous access sites (e.g. PICCs) may be cleaned weekly (at dressing change), and short‐term central venous catheters (CVCs) may be cleaned weekly, daily or more frequently (as these are associated with the highest infection risk). The insertion site should be checked regularly for signs of phlebitis (erythema, pain and/or swelling) or infection using the Visual Infusion Phlebitis (VIP) scoring system or similar (DH [113], Gorski et al. [181], Jackson [226], RCN [381]). Complaints of soreness, unexpected pyrexia, and damaged, wet or soiled dressings are reasons for immediate inspection and renewal of the dressing.
Securement and dressings
There are a number of securement devices and dressings available. The aim of a securement device is to secure the device to the skin and prevent movement of the device, which in turn will reduce the risk of mechanical phlebitis and infection. Decurement devices also prevent dislodgement. Types of securement include tape, sutures and self‐adhesive anchoring devices applied to the skin (e.g. StatLock) (Luo et al. [282], Moureau and Iannucci [334]) and anchor devices that are placed just beneath the skin at the insertion site (e.g. SecurAcath) (Egan et al. [137]). Suturing can result in inflammation and bacterial colonization of the exit site (Schears [402]) and is no longer recommended (Maki [289]), particularly with PICCs (Nakazawa [343]). StatLocks have been shown to result in significantly longer duration in situ and fewer total complications (Luo et al. [282], Schears [402], Yamamoto et al. [478]) but adhesive devices can cause skin surface irritation. To avoid this, anchoring devices such as SecurAcath are now recommended for the securement of percutaneous catheters (NICE [353]) and they have been shown to save time and prevent catheter dislodgement during dressing change (Goossens et al. [178]). Alternatively, the use of tissue adhesives, traditionally used for wound closure (Singer and Thode [416]), has become a novel method of securing VADs and its clinical use continues to increase due to the ability to ‘seal’ the insertion site. This prevents ooze and entry of micro‐organisms, has bacteriostatic properties and provides high tensile strength (Corley et al. [88], Jeanes and Martinez‐Garcia [229], Scoppettuolo et al. [408], Simonova et al. [415]). Cyanoacrylate (medical‐grade superglue) applied directly to the exit site, and under the hub on insertion, is an effective way to reduce micro‐movements, achieve haemostasis when there is oozing from the exit site and provide further infection prevention (Rickard et al. [383]).
Types of dressings include sterile gauze and transparent dressings. The recommendation for a CVAD site is an intact, dry, adherent semi‐occlusive transparent dressing (DH [117], Loveday et al. [278]). The RCN ([381]) recommends the use of transparent IV film dressings. These dressings allow observation of the exit site without the need to remove the dressing. They are also moisture permeable, thereby reducing the collection of moisture under the dressing (Casey and Elliott [65]). The key benefits of transparent IV film dressings (i.e. intravenous vapour‐permeable film dressings) are their waterproof nature, conformability and moisture vapour transmission rate (CET [68]). The moisture vapour transmission rate (MVTR) is the measurement of water vapour diffusion through a material and it defines the breathability of IV film dressings. It is important that the skin under the dressing maintains its normal function to avoid skin irritation or maceration without excessive proliferation of skin flora (Rickard et al. [383]).
Newer chlorhexidine‐impregnated dressings can be beneficial in preventing catheter colonization (Safdar et al. [395]). These products include a chlorhexidine gluconate antimicrobial transparent dressing, which contains a chlorhexidine gel pad, which is integral to the dressing and has been shown to allow visualization of the site, facilitating absorption of fluid under the dressing (Moureau et al. [332], Pfaff et al. [370]). It has been shown to prevent the regrowth of microbial skin flora (Maki [291]) and reduce the incidence of bloodstream infection (Jeanes and Bitmead [228]). This can also be achieved by attaching a hydrophilic polyurethane absorptive foam patch impregnated with chlorhexidine gluconate under the transparent dressing, which has been shown to reduce the rate of catheter colonization and demonstrated significant reductions in the associated rate of catheter‐related bloodstream infection (Ho and Litton [213], Ruschulte et al. [392], Timsit et al. [441]). However, the foam patch does not enable insertion site visualization.
Methods of maintaining a closed intravenous system
If equipment becomes accidentally disconnected, air embolism or profuse blood loss may occur, depending on the condition and position of the patient (Perucca [369]). Accidental disconnection poses a greater risk in patients with central venous or arterial access devices than in those with peripheral venous devices. This is because of the amount of air that may be introduced via a CVAD and the speed with which it may enter the pulmonary vessels or the speed of haemorrhage. Luer‐Lok provides the most secure connection and all equipment should have these fittings: that is, administration sets, extension sets and injection caps (Dougherty [123]). Needle‐free systems provide a closed environment, which further reduces the risk of air entry (Dougherty [123], [124], Kelly et al. [243]). Care should be taken to clamp the catheter firmly when changing equipment. Connections must be double checked and precautions taken to prevent the introduction of air into the system when making additions to, or taking blood from, a CVC (Dougherty [123]). Another way of maintaining a closed intravenous system is the use of newer peripheral intravenous cannulas with integrated extension tubing (closed system) (Shaw [411]) (see Figure 17.15).
Methods of preventing damage of the vascular access device and performing a repair
Catheters are made of non‐resealable material, so penetration by a needle creates holes and a catheter can rupture if excessive force is exerted (Gorski et al. [182]). Pinch‐off syndrome can also result in a transected and potentially embolized catheter segment (Gorski et al. [182]). Temporary and permanent repairs can be performed depending on where the catheter is damaged and the type of catheter (Dougherty [123], [128]). Damaged catheters must be repaired or removed, as any opening in the catheter can act as a point of entry for bacteria or air (Dougherty [128]). The repair of a ruptured tunnelled CVAD is often the least invasive and most viable intervention for certain patient populations (Gordon and Gardiner [179]). Catheter repairs do not increase the rate of infection despite longer dwell times (Gordon and Gardiner [179], Koh et al. [246]).
Artery forceps or sharp‐edged clamps should not be used to clamp the catheter. A smooth clamp should be placed on the reinforced section of the catheter provided for clamping (Dougherty [123]). If a reinforced section is not present, placing a tape tab over part of the catheter can create one. A second alternative is to move the clamp up or down the catheter at regular intervals to reduce the risk of wear and tear in one place (Dougherty [123]).
Use of the correct syringe size in accordance with the manufacturer's guidelines will reduce the risk of catheter rupture (Gorski et al. [181]). However, appropriate syringe size alone will not be sufficient to prevent catheter rupture. If resistance is felt and more pressure is applied to overcome it, catheter fracture can result regardless of the syringe size (Hadaway [190], Macklin [284]). Nurses must be familiar with the action to be taken to minimize any risk to patient safety in this event. Immediate clamping of the catheter proximal to the fracture or split is essential to prevent blood loss or air embolism (Gorski et al. [182]). The split area should be cleaned vigorously using a chlorhexidine swab and friction for at least 30 seconds, left to air dry and then covered with an occlusive transparent dressing until emergency repair equipment has been collected (Gordon and Gardiner [179]). The procedure must be done using an aseptic technique. The repair should only be undertaken by a healthcare professional who has the necessary knowledge and skills, and according to the manufacturer's instructions (Dougherty [128]).
Methods of maintaining patency
Patency is defined as the ability to infuse through and aspirate blood from a VAD (Dougherty [123]). It is important for the patency of the device to be maintained at all times. Blockage can lead to device damage, infection, inconvenience to patients and disruption to drug delivery. Maintaining patency and avoidance of infections are key objectives in long‐term CVAD usage (Kumwenda et al. [252]). Occlusion of a device is usually the result of one or more of the following:
- clot formation (Figure 17.3) due to (a) an administration set or electronic infusion device being turned off accidentally and left for a prolonged period or (b) insufficient or incorrect flushing of the device when not in use; thrombotic occlusions are responsible for up to 58% of all occlusions (Hadaway [194])
- precipitate formation due to inadequate flushing between incompatible medications (Dougherty [123]).
Figure 17.3 Clot formations. Source: Reproduced from Macklin and Chernecky ([287]) with permission of Elsevier.
Kinking or pinch‐off syndrome may also impair the patency of the device. Meticulous intravenous technique will prevent the majority of these problems.
Two main types of solution are used to maintain patency in VADs: heparin and 0.9% sodium chloride. All devices should be flushed with 10–20 mL 0.9% sodium chloride after blood withdrawal and then flushed again with the appropriate flushing solution (Dougherty [123], [124], Gorski et al. [181], RCN [381]).
Maintaining patency can be achieved by one of the following:
- a continuous infusion to keep the vein open, either by the patient being attached to an infusion of 0.9% sodium chloride via a volumetric pump, which reduces comfort and mobility, or by use of an elastomeric device, which is less restrictive and has been able to reduce loss of patency by 50% (Heath and Jones [206])
- intermittent flushing (previously known as a ‘heparin lock’) (Box 17.1).
Box 17.1
Advantages and disadvantages of intermittent flushing
The advantages of intermittent flushing compared with a continuous infusion are:
- it reduces the risk of circulatory overload
- it reduces the risk of vascular irritation
- it decreases the risk of bacterial contamination as it eliminates a continuous intravenous pathway
- it increases patient comfort and mobility
- it may reduce the cost of intravenous equipment (Phillips [371]).
The major disadvantage is the necessity for constant vigilance and regular flushing (Weinstein and Hagle [465]).
When used for intermittent therapy, the device should be flushed after each use with the appropriate flushing solution (guidelines for volumes, concentrations and frequency of flushing are commonly established within individual institutions). It is now well established that flushing with 0.9% sodium chloride can also adequately maintain the patency of a cannula (Goode et al. [174], White et al. [468]). This avoids side‐effects such as local tissue damage, drug incompatibilities and iatrogenic haemorrhage, which can occur with heparin (Goode et al. [174], NPSA [359]). As well as being cost‐effective, it appears that daily or twice‐daily flushing with a volume of 2–5 mL 0.9% sodium chloride is appropriate (Goode et al. [174], LeDuc [265]).
The consensus about the solution to use for maintaining patency of CVADs has changed in the past few years from heparinized saline to 0.9% sodium chloride (Dal Molin et al. [100], [101], Lopez‐Briz et al. [276], [277], Pittiruti et al. [376], Solinas et al. [420], Zhong et al. [481]) and most guidelines favour the use of 0.9% sodium chloride for flush and lock purposes for any type of non‐dialysis CVAD (Gorski et al. [181], Loveday et al. [278], RCN [381], Sousa et al. [423]). However, some local policies continue to recommend heparinized saline to maintain the patency of CVCs; in particular, for intermittent or infrequent use of implanted ports (Kefeli et al. [240], Palese et al. [366]), it is recommended to use a stronger solution of heparin, usually 500 international units of heparin in 5 mL 0.9% sodium chloride (Berreth [29], Perucca [369]). There is a lack of consensus on the optimal frequency of flushing of CVADs (Conway et al. [85], Goossens [177], Green et al. [185], Mitchell et al. [319], Sona et al. [421]) and practice varies between organizations. Flushing regimens ranging from once daily to once weekly have been found to be effective. PICCs and skin‐tunnelled catheters (STCs) normally require flushing once a week, while recommendations for implanted ports range from monthly (Vescia et al. [453]) to every 6 weeks (Kefeli et al. [240]) to every 8 weeks (Hoffman [216], Palese et al. [366]) to every 3–4 months when not in use (Kuo et al. [253], Solinas et al. [420]). The decision regarding which solution and frequency to use to maintain patency is often based on local data (Bolton [47], Hadaway [193]).
Using the correct techniques to flush the VAD has been highlighted as one of the key issues in maintaining patency (Baranowski [16], Goodwin and Carlson [175]). Flush efficiency is more about flushing technique than solution used (Ferroni et al. [146], Goossens [177]). There are two stages in flushing:
- A push–pause, pulsatile or turbulent technique is more effective when rinsing the internal diameter of a catheter than laminar or continuous low flow infusion (Goossens [177], Guiffant et al. [188]). These techniques create turbulent flow when the solution is administered, regardless of type and volume. This removes debris from the internal catheter wall (Cummings‐Winfield and Mushani‐Kanji [96], Goodwin and Carlson [175], Guiffant et al. [188]).
- The procedure is completed using the positive pressure technique. This is accomplished by maintaining pressure on the plunger of the syringe while disconnecting the syringe from the needle‐free connector, which prevents reflux of blood into the tip, reducing the risk of occlusion (Berreth [29], Gorski et al. [181], Hadaway [194]).
Manufacturers have now produced needle‐free connectors, which are intended to reduce incidence of occlusion and infection (Btaiche et al. [55], Chernecky and Walker [74], Hadaway [195], Macklin [285]). Blood reflux is caused by changes in pressure within intravascular catheters upon connection or disconnection of a syringe or intravenous tubing from a needle‐free connector (Hull et al. [220]). Some needle‐free connectors enable a positive ‘displacement’ flush and achieve positive pressure without practitioners being required to actively achieve the positive pressure (Weinstein and Hagle [465]). They have been shown to reduce significantly the incidence of catheter occlusion (Berger [28], Lenhart [267], Mayo [302], Rummel et al. [391]). However, changes in pressure, differing with type of needle‐free connector, may result in fluid movement and blood reflux, which can contribute to intraluminal catheter occlusions and increase the potential for CVAD‐associated bloodstream infections (Hull et al. [220]). Therefore, it is recommended to carry out a risk assessment prior to routine use and to change the needle‐free connector regularly (e.g. once per week) (Casey et al. [66], Hadaway [194]). Negative pressure devices require positive pressure on the syringe. Neutral displacement connectors allow no blood reflux to occur on disconnection and they are not dependent upon flushing technique so can be clamped before or after syringe disconnection (Casey et al. [66], Chernecky et al. [73]).
Excessive force should never be used when flushing devices. When a catheter lumen is totally patent, internal pressure will not increase during flushing (Dougherty [128], Hadaway [191]). However, if resistance is felt (due to partial occlusion) and a force is applied to the plunger, particularly with a small‐volume syringe, high pressure can result within the catheter, which may then rupture (Conn [83], Dougherty [128], Gorski et al. [182], Hadaway [191], Macklin [284]). It is therefore recommended that the device is checked first with a 10 mL or larger syringe containing 0.9% sodium chloride (Hadaway [191], Macklin [286], RCN [381]). However, smaller syringes should only be used to administer drugs where there is no pressure or occlusion and where it is not possible to further dilute drugs and administer them in a large syringe (Hadaway [190], Macklin [284]). The composition of the individual device determines the maximum pressure that can be exerted. There are now CVADs available (PICCs, STCs and implanted ports) and midlines that allow computed tomography (CT) contrast to be administered via a pressure injection pump at 3–5 mL per second without damaging the device.
If a catheter becomes occluded, the nurse should establish the cause of the clot, occlusion or precipitation (Bolton [47], Gorski et al. [181]). If precipitation occurs, instillation of hydrochloric acid or ethyl chloride may be required (Doellman [120], Hadaway [194]). Thrombus formation (both intraluminal and external) and formation of a fibrous connective tissue sheath (traditionally described as ‘fibrin sheath’) plays a central role in CVAD dysfunction and can limit the efficacy of treatment and the longevity of the CVAD, and create life‐threatening situations where the relevant therapy cannot be provided (Gallieni et al. [163], Kumwenda et al. [252]). There are two types of thrombotic occlusion:
- Partial withdrawal occlusion (Figure 17.4): this is usually caused by fibrin sheath formation and identified by absent or sluggish blood return while fluids can be infused (Nakazawa [343]). Fibrin sheaths can result in seeding of bacteria and drug extravasation (Mayo [301], [302]) and can be resolved by the instillation of a thrombolytic agent, such as urokinase or alteplase (Dougherty [123], Fanikos et al. [143], Haire and Herbst [196], Kumwenda et al. [252], Weinstein and Hagle [465]).
- Total occlusion: this is when there is an inability to withdraw blood or infuse fluids or medications. This can be resolved by instillation of a thrombolytic agent (Baskin et al. [21], [22], Deitcher et al. [112], Kumwenda et al. [252], Ponec et al. [377], Syner‐Kinase [432], Timoney et al. [439]).
Figure 17.4 (a) Algorithm for partial withdrawal occlusion – that is, fluids can be infused freely by gravity but blood cannot be withdrawn from the catheter. (b) Evidence based protocol for management of occluded CVADs in non‐renal settings. Source: (a) Adapted from UCL Hospital Central Venous Catheter Policy.
If the occlusion is caused by a clot, gentle pressure and aspiration may be sufficient to dislodge it. Silicone catheters expand on pressure and allow fluid to flow around the clot, facilitating its dislodgement. This should only be attempted using a 10 mL or larger syringe. Smaller syringes should never be used as they create a greater pressure (Camp‐Sorrell et al. [60], Gorski et al. [182]). This can result in rupture of the catheter, leading to loss of catheter integrity (Gorski et al. [182]). Clearance of a catheter occlusion and instillation of thrombolytic agents should be performed using a three‐way tap and negative pressure (Gabriel [161], Gallieni et al. [164], McKnight [307]). The establishment of negative pressure involves creating a vacuum by aspiration of the air or dead space within a catheter (Gabriel [161], Dougherty [123], Moureau et al. [336]). Another method is use of the percussion technique (Johnston [235], Stewart [430]). Unblocking a catheter is not a quick procedure and it can take some time to achieve success.
Methods of maintaining a correctly positioned catheter tip
A CVAD is defined as a catheter whose tip terminates in the lower third of the superior vena cava (SVC) (Gorski et al. [181], RCN [381], Wilkes [472]). Optimal tip location is a subject of debate, although there are some common recommendations (Chantler [69]):
- The vein should be large with a high blood flow (this dilutes drugs and reduces the risk of damage to the vein intima).
- The end of the catheter should be in the long axis of the vein and not abutting the vessel wall (to reduce damage to the intima and avoid inaccurate pressure readings).
- The tip should be beyond the last venous valve.
Ideally, the tip of a CVAD should be positioned in the proximity of the cavo‐atrial junction (CAJ), in a ‘safe’ area, such as the lower third of the SVC and the upper portion of the right atrium (Bodenham et al. [43], Fletcher and Bodenham [150], Lamperti and Pittiruti [261]).
The tip location of a CVAD will affect the catheter's performance; if the tip is too high or too far within the right atrium, it may be sucked against the adjacent wall when aspiration is applied (Vesely [454], [455]), and this increases the risk of thrombosis (Gallieni et al. [164]). A catheter tip positioned against a vascular wall may also become a source of persistent irritation, potentially leading to the creation of a nidus for thrombus formation (Bodenham et al. [43], Galloway and Bodenham [165], Mayo [302]). This is reported more frequently in patients who have left‐sided placements (Chantler [69]). The arguments for right atrial tip placement are that the tip is in a large chamber, thus preventing contact with the vein wall, and the rapid blood flow also prevents accumulation of thrombin and minimizes irritation of substances. The disadvantages of this tip position are an increase in cardiac arrhythmias (although this may be associated with the insertion of the guidewire as its incidence is reduced by image guidance) and catheter‐induced perforation and cardiac tamponade (although this has been reduced by using softer materials and imaging guidance) (Chantler [69], Lamperti and Pittiruti [261], Vesely [454]).
The tip position can also change during its time in situ. The position of a CVAD tip moves with respiration and patient position (Bodenham et al. [43]). For example, the final position of a PICC is dependent on the insertion site and the position of the patient's arm, and the catheter can move at least 2 cm further into the right atrium on movement (Forauer and Alonzo [152], Spencer [424]). PICCs placed in the left arm tend to move more than those placed in the right arm, and those placed in the basilic vein are more likely to move than those placed in the cephalic vein (Vesely [455]). Anatomical changes occur with subclavian and internal jugular insertion when patients sit upright following insertion and the catheter tip can move upward. In an STC this can be 2–3 cm, particularly in overweight patients of either sex or female patients with substantial breast tissue. Large‐diameter catheters can move more than smaller ones and subclavian more than internal jugular placements.
The tip of the catheter can also move during high‐flow flushing and power injection of contrast material (Morden et al. [324], Spencer [424]). There have been reports of CT‐PICC displacement events during power injection of contrast for CT scanning (Morden et al. [324]). This is less likely to happen if the tip of the catheter is placed in the distal SVC or within the CAJ (Spencer [424]).
A correctly placed catheter tip will probably be one that undergoes a range of movement between the SVC and upper right atrium (Dougherty [123], Nakazawa [342], Spencer [424]). The direction of the catheter can be tracked with electromagnetic navigation devices and this prevents malposition (La Greca [256]). Tip position is determined by:
- taking a chest X‐ray using the posterior anterior view (Wise et al. [474]) (Figure 17.5)
- using electrocardiogram (ECG) technology (intracavitary ECG), which has been shown to provide accurate and consistent guidance of the tip to the lower third of the SVC or CAJ; it also removes the time needed to interpret an X‐ray and the cost of the X‐ray, reduces patient exposure to radiation and saves time repositioning the tip or catheter (Moureau et al. [331], Oliver and Jones [364], Pittiruti et al. [375]) (Figure 17.6).
Figure 17.5 Chest X‐ray showing catheter tip correctly positioned (arrow).
Figure 17.6 Electrocardiogram (ECG) pattern indicating raised P waves.
Catheter tip position can also be detected by transoesophageal echocardiogram (TOE) but this is expensive, invasive and impractical in most patients (Lamperti and Pittiruti [261]).
Anticipated patient outcomes
The patient will have a functioning VAD.
