- Email: [email protected]
Techniques in Vascular and Interventional Radiology: Pediatric Central Venous Access
Techniques in Vascular and Interventional Radiology: Pediatric Central Venous Access Jack-Nghia Vo, MD, Fredric A. Hoffer, MD, FSIR, and Dennis W.W. Shaw, MD Interventional radiologists (IRs) with expertise in image guidance have an inherent skill set for the safe and reliable placement of central venous access catheters (CVACs) in children. Above and beyond the technical requirements, IRs have an integral role as consultants in evaluating children for the most appropriate catheter to meet their short- and long-term needs. This article is meant to serve as a reference for decision making along with tips and pearls on how we approach placing CVACs in pediatric patients at our Children’s Hospital. Tech Vasc Interventional Rad 13:250-257 © 2010 Elsevier Inc. All rights reserved. KEYWORDS venous access, children, venous catheter, central venous access
T
he demand for the vascular and interventional radiology (VIR) specialty to place central venous access catheters (CVACs) in children has dramatically increased since the demonstration that image guidance enhances the safety, reliability, and cost-effectiveness of central catheter placement.1 Furthermore, as interventional radiologists (IRs) take a greater role as clinical consultants, the model is set for these providers to participate in assessing the appropriate access requirements for children in conjunction with the pediatric clinical services, as well as managing any post procedure catheter-related problems should they arise. The placement of a CVAC in infants and young children can be technically challenging, mainly because of their smaller size. Prior to initiating the process of placing a CVAC in a child, several questions should be addressed during the evaluation by the VIR service, including: (a) the indication(s); (b) catheter type and number of lumens required (for medication, total parenteral nutrition, hemodialysis [HD], etc.); (c) the expected duration of need; and (d) the appropriate location for insertion and positioning of catheter tip. With this in mind, we set out to mitigate the potential distress that may arise for the IRs who receive these consults and hope to offer a reference they can use in the care of children.
Department of Radiology, Seattle Children’s Hospital and The University of Washington, Seattle, WA. Address reprint requests to Jack-Nghia Vo, MD, Seattle Children’s Hospital and The University of Washington, Department of Radiology, Section of Pediatric Interventional Radiology, Pediatric Radiology and Vascular Interventional Radiology, 4800 Sand Point Way NE, Seattle, WA 98105. E-mail: [email protected]
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Planning for the Placement of a Central Venous Access Catheter The most common indications for central venous access in children include the need for central venous infusion of medications, including chemotherapy, parenteral nutritional, or prolonged intravenous (IV) antibiotic course of greater than 7-10 days. Central vascular access is also required for children in need of HD/apheresis. An indication that is more common in children than adults is the need for frequent blood draws or a child with difficult peripheral venous access. Optimizing the child’s coagulation profile before performing various vascular access procedures is required. For tunneled CVAC and implantable ports, the goal for the International Normalized Ratio is ⬍1.7 with a minimum platelet count of 50,000/mm3 for a tunneled central vascular line (CVL) and 70,000/mm3 for an implantable port. Under normal circumstances, where the risk of an arterial puncture is unlikely as determined by an ultrasound (US) evaluation, the desired platelet count is ⬎25,000/mm3 for the placement of a peripherally inserted central catheter (PICC). We do not routinely require aspirin to be withheld for PICCs. Ideally, aspirin is withheld 5-7 days before placement of an implantable port or tunneled CVAC. In emergent circumstances or when the clinical condition does not permit the optimization of the coagulation parameters, we then have blood products made available and consider a non-tunneled central venous access or a PICC.
Pediatric central venous access
251
We will discuss the clinical settings in which we use various CVACs. Then we will describe our techniques and pearls for their placement in children.
routes, as the internal jugular (IJ) with its larger comparative diameter to the catheter is less prone to thrombose and occlude then a peripheral venous access site.5
Peripherally Inserted Central Catheter
Tunneled Central Venous Lines
Children with an acute illness and who require venous access of intermediate term (at least 10 days and ideally ⬍2 months but no more than 6 months) for medication infusion can be well served with a PICC. Typically, this includes children with appendicitis, septic arthritis, or osteomyelitis in whom a prolonged course of IV antibiotics is required. We also consider the placement of PICCs in children who have an acute illness and are in need of frequent or have very difficult blood draws. This is a strategy employed to minimize traumatic experiences (for both the child and parents) that can arise with repeated venous puncture attempts. We use a 3-Fr single or 4-Fr double lumen PICC catheter. The 3-Fr single lumen PICC with the tip positioned centrally at the level of the atrial caval (AC) junction (just below the inferior edge of the right main stem bronchus) is reliable for use in blood draws. The 4-Fr double lumen PICC is limited for use in children who require the simultaneous infusion of incompatible medications; the smaller individual luminal diameters make blood draws more difficult. Occasionally, in the smallest of neonates (⬍2-3 kg) who require a double lumen catheter, we will use a 2.7-Fr dual lumen PICC (Becton Dickenson, Sandy, UT). Our philosophy is to use the smallest diameter catheter that can meet the child’s needs to minimize thrombosis of the engaged vessel and the fewest required lumens to reduce the risk of infection. A note of caution for PICCs placed in the upper extremity with the child’s arm in the abducted position: When the arm is repositioned in a neutral position with the arm at side (essentially adducted) or flexed at the elbow, the tip will migrate, potentially leading to a significant change in the catheter tip position that is deeper into the chest (Fig. 1).2 This change in position is most prominent in neonates, where it can also have the greatest clinical significance. Although rare, there are several reports of fatal cardiac tamponade associated with atrial perforation from central venous catheters with the tip located in the right atrium.3 Many NICUs by policy do not allow placement of PICCs below the AC junction into the right atrium. This is in contrast to adults, in whom this is preferable. In children with congenital heart disease who are postoperative, it may be desirable to position the PICC with the tip in the subclavian vein, to avoid risk of shunt thrombosis. Communication with the pediatric cardiac services in advance may minimize malposition and the need for revision in these patients. Upper extremity PICCs (and subclavian vein CVLs) are contraindicated for children who have a history of renal insufficiency or could be anticipated to require HD in the future.4 We also limit upper extremity PICC use in children with chronic conditions that necessitate frequent and recurring venous access needs, most notably children with small bowel or solid organ transplants. Due to the expected recurrent need for venous access, using the jugular route in these children can be an effective means to preserve vascular access
We favor the use of a tunneled CVL in children when there is the need for an extended duration of venous access or an intermediate term access where an appropriate sized PICC line is not feasible or is contraindicated. Tunneled CVLs are ideal for children with chronic conditions requiring reliable extended venous access with regular use. In addition, we routinely place tunneled CVLs in children and infants in the intensive care or cardiac care units. These children are often in need of a stable and reliable central access route that is able to accommodate countless infusion sources. A tunneled CVL with a retention cuff further aids in the security of the catheter from unintentional dislodgement and reduces the risk of infection. We use a 5-Fr single or 6-Fr dual lumen Power-Line (Bard Access Systems, Salt Lake City, UT), both with a Dacron retention cuff. We try to limit these catheters to children who are at least 1 year of age and more than 10 kg in weight. The diameter of the IJ in infants less than 6 months of age and 12 kg is frequently smaller than 5 mm in diameter, and the use of a 6-Fr catheter (2-mm diameter) has a higher complication rate.6
Tunneled Hemodialysis/Apheresis Catheters Adequate flow rates are necessary for HD or apheresis catheters. Although the largest catheters will permit the greatest flow rates, the highest achievable flow rate is not absolutely necessary. We consider the catheter and patient/vessel size to achieve flow rates sufficient for reliable, timely, and adequate HD/apheresis sessions balanced with the desire to minimize complications related to the presence of the larger bore catheter within the venous lumen. Neonates and infants with their lower overall total blood volume do not need the ultrahigh flow rates commonly required for adults to complete a timely HD or apheresis session. The estimated total intravascular blood volume in children ⬍10 kg is 80 mL/kg and for those ⬎10 kg is 70 mL/kg. In children ⬍20 kg, we use the 6-Fr dual lumen Power-Line (cut to length) tunneled from the anterior chest to the IJ as access for apheresis. Children ⬍10 kg and in need of renal replacement are prepared for peritoneal dialysis. The IJ vein diameter of children 20-40 kg will typically accept an 8-Fr dual lumen tunneled and cuffed HD catheter (Medcomp, Harleysville, PA). In children who are 40-60 kg, we use a 10-Fr split lumen HD catheter (Medcomp). Children ⬎60 kg essentially have adult habitus and requirements. Under most circumstances, we favor the use of the right IJ access route. The right IJ is larger than the left in 70% of children and provides a direct path for final position of the distal catheter tip into the high right atrium to accommodate the higher flow rates and to help decrease the development of catheter tip thrombus formation, compared with those in the superior vena cava (SVC).7 In neonates with congenital cardiac anomalies who are being prepared for a cardiac trans-
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Figure 1 (A) A 2-month-old girl with mastoiditis, requiring an extended duration of IV antibiotics. Initial access was obtained with arm in the typical abducted position. The tip of the PICC catheter (arrow) appears well positioned at the level of the AC junction with the arm still in the abducted position. (B) With the arm adducted to the child’s side, the catheter tip (arrow) is now 2 vertebral body lower, into the lower right atrium. (C) Final position of the PICC catheter tip (arrow), appropriately repositioned to the AC junction with the arm in the adducted position.
plant or have had/need multistaged cardiac interventions and require access for both infusion of medication and apheresis, we place the catheter via the left IJ route. This route allows for greater intravascular catheter length and stability, decreasing the risk of complete vascular dislodgement if an unintentional event were to occur and the catheter is withdrawn several centimeters. We avoid use of the subclavian vein.8
Implantable Ports Implantable ports are ideal for children who require intermittent venous access for infusion therapy or blood draws over an extended duration. The classic candidate for a port is a pediatric oncology patient, but additional candidates include those with cystic fibrosis or thalasemias and other chronic disorders with frequent exacerbations. Mini-ports or arm
ports are preferred for their low profile in children who generally have less subcutaneous tissue. Strict adherence to guidelines for a standard surgical hand scrub and skin preparation is required for implantable ports placed in children within the interventional radiology suite.9 We routinely use antibiotic prophylaxis for skin flora coverage, 25 mg/kg (maximum 1 g) of IV cefazolin given at least 30 minutes before initiation of a skin incision.
Technique for Placement of a Central Venous Access Catheter in Children Peripherally Inserted Central Catheter The child’s arm is evaluated with US above the antecubital fossa. The arm is circumferentially prepared from the forearm to the axilla and a sterile tourniquet positioned. The arm is
Pediatric central venous access placed in the abducted position with the hand supinated. Using a high-frequency linear US probe (15 MHz vascular access probe), the target vessel is visualized and confirmed by compression and color Doppler to be venous. (A note of caution: If a tourniquet is applied too tightly in small children, the brachial artery may not demonstrate pulsatile color flow and may be compressible mimicking a venous structure. It may be necessary to release the tourniquet and reconfirm the nature of the vessel before accessing it.) After axial localization, the target vein is visualized in the longitudinal view. The access needle is advanced under real-time US visualization for direct venous puncture (Fig. 2). In the dehydrated child, the intravascular volume can be quite depleted and a bolus of additional IV maintenance fluid can aid in maximizing the diameter of the venous target (along with using the tourniquet). We use a 21-gauge long beveled percutaneous entry needle, described as a “venous bevel” by the manufacturer (Cook Medical, Bloomington, IN), as our access needle of choice. We feel that this longer bevel can more effectively pierce the frequently mobile, displaceable, and compressible vein encountered in children. Once venous entry is achieved, we use the standard Seldinger technique and advance a measuring wire under intermittent pulse fluo-
253 roscopic visualization to the AC junction. Although, a peel-away sheath (typically 0.5 Fr larger in diameter than the PICC catheter itself) is provided in most image-guided PICC sets, we find that this is not often required. After using only the inner dilator to dilate the tract, the cut-tolength catheter will frequently pass over the wire through the subcutaneous tissue into the vein with only minimal resistance. If necessary, the resistance can typically be overcome by initially permitting both the catheter and wire to be advanced simultaneously for a short distance. Once the resistance is overcome, the wire can be pinned in place as the catheter is advanced into position over the wire. We secure the catheter with a suture at the skin insertion site and an adhesive retention device for the wings. Occasionally, we will suture the wings of the PICC if the child is prone to catheter dislodgement or limited in additional venous access sites. The insertion site is covered with an antimicrobial disk at the skin entry site then covered with a clear adhesive covering. The PICC is secured after confirming appropriate catheter tip position with the arm adducted to the side.10 In circumstances in which the initial standard wire supplied with the PICC kit is not able to be advanced centrally, we will insert the dilator over the wire and perform a
Figure 2 (A) The left arm of an infant sterilely prepared circumferentially from the forearm to the axillae. A tourniquet is positioned for later use to help distend the target vein for venous entry. The hand is supinated and covered with a clear plastic drape. (B) Long view of the access needle distorting the superficial surface of vein (arrow) before venous entry. (C) US image of access needle tip (arrow) within the basilic vein upon flashback of blood at the hub. (Color version of figure is available online.)
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venogram. A 0.018 hydrophilic wire can often be manipulated beyond a stenosis or through a collateral vessel centrally. In small nonambulatory neonates when the venous structures of the arm are not sufficient or available for placement of a PICC, a tunneled femoral line may be an option. We obtain access in the femoral vein (or saphenous vein) and place the standard 3-Fr PICC catheter. When using the lower extremity for access, we will make the skin entry with the needle in the mid to upper thigh remote from the inguinal fold. This is to keep the skin entry site of the catheter away from the diaper and therefore reduce soiling and the associated increased risk of line infection. With US guidance and using the US probe as a nice spacer, away from the inguinal fold, the access needle is used to create a long shallow subcutaneous course before puncture of the common femoral vein. Alternatively, the peel-away sheath can be used to create a tunnel in the classic fashion, with the PICC fed through it to the vessel entry site. While holding the US probe with the forefinger and thumb, the fourth and fifth fingers can be used to apply compression above the inguinal fold as a method to distend and increase the diameter of the common femoral vein. Following venous entry, a standard Seldinger technique is then employed for placement of the catheter. The catheter tip is positioned at the junction of the inferior vena cava (IVC) and the right atrium (Fig. 3). Tunneled Internal Jugular Catheter A rolled towel is placed under the child’s shoulder and the head is turned to extend the neck. A high-frequency linear vascular US probe is used to localize the IJ just above the clavicle. A positive inspiratory pressure or valsalva maneuver can be used to potentially increase the cross-sectional area of the IJ in small children. A wide skin preparation is performed from the level of the auricle to below the nipple. A micropuncture needle is advanced under real-time US for direct puncture via the lateral aspect of the IJ (using either a single or, if needed, a double wall puncture technique) (Fig. 4). The 0.018 Mandril guidewire is advanced into the high right atrium under fluoroscopy. The micropuncture sheath is advanced and the wire tip is positioned for appropriate intravascular length measurement. In infants and neonates, the wire and sheath are advanced into the IVC to permit a sufficient stable intravascular component. For HD catheters, the wire is exchanged for a standard 0.035 J-tipped wire or a 75-cm Super stiff Amplatz wire (Boston Scientific, Miami, FL). The wire is positioned into the IVC to provide a stable platform for the advancement of the peel-away sheath and minimize the risk for inadvertent shearing/rupture of a central venous structure that could potentially occur if resistance is met during sheath advancement or dilation over a mobile wire. The peel-away sheath for the 5- and 6-Fr Power-Lines advance over a 0.018 wire. An appropriate position for the skin exit site is localized along the anterior chest wall. For smaller children in whom the tunneled path may need to be longer relative to the chest than typical for adults, avoid a path near the nipple. With infants and neonates, due to their small chest size, a more lateral location may need to be considered.
Figure 3 (A) Axial gray-scale US of right groin over the femoral head in a 3-kg child needing stable venous access for therapy. Common femoral artery (A) was noncompressible. Saphenofemoral vein junction (V) was compressible. (B) Image demonstrates the extended “tunneled” subcutaneous path of the access needle before entry into the femoral vein (V) overlying the femoral head (H), used to keep catheter access site remote from the diaper are and reduce the risk of infection.
Using the micropuncture needle (same needle used for IJ puncture), we anesthetize the intended tunneled tract with a premixed solution of 1% lidocaine and epinephrine mixture, 1:100,000 (Hospira, Lake Forest, IL). An appropriate length tip-to-cuff HD catheter is selected based on the measurement of the intravascular component plus the length of the tunneled tract. The Power-Lines are cut to length based on the previously measured intravascular length. We ideally position the Dacron cuff 1-2 cm above the skin exit site. After insertion of the catheter tubing through the peelaway sheath, while the child is in the Trendelenburg position, the venous entry site is gently massaged to smooth the curve of the catheter tubing in the neck. The use of a lateral venous entry approach as well as a tunneled path that approaches the venous entry site laterally aids in forming a smooth transitional curve in children and helps minimize the risk of an acute angle prone to “kink.” The lumen(s) are flushed and aspirated to assure function. With HD catheters, a 20-mL syringe is used to approximate the flow rates required. The HD catheters are positioned with the distal tip in
Pediatric central venous access
255 plantable device will be selected based on the thickness and depth of subcutaneous tissue over the chest. Ideally, the skin and subcutaneous tissue overlying the port are about 5 mm in thickness. The device is placed on the skin surface over the intended pocket site and outlined with a sterile marker. This allows a good visual landmark aiding the formation of an appropriate sized pocket following adequate local anesthetic infiltration (Fig. 6). The port pocket is formed using blunt dissection mainly with a gauze-covered finger after a single continuous incision is made the width of the port device. The pocket should be made just large enough to fit the implantable device and not permit it to “flip.” We do not routinely stitch the device in place within the pocket. The catheter tubing is tunneled from the pocket and pulled out to the venotomy site and cut to the appropriate measured length. The catheter tip is positioned at the AC junction. The port pocket is closed with an interrupted deep fascial layer closure using 2-0 or 3-0 absorbable suture and 4-0 running subcuticular resorbable stitch. Alternative Access We have occasionally used transhepatic, transrenal, and direct suprarenal IVC access routes when traditional routes have been exhausted, typically in children with chronic disease states. Our goal is to avoid getting to this point. IRs involved in the care of children with chronic conditions really need to advocate early on vascular preservation principles. However, if these routes are used, considerations for respiratory motion and its relationship to the catheter must be taken into account.
Figure 4 (A) Photo showing the use of a high-frequency “hockey stick” linear US probe to localize the left internal jugular vein in the axial view just above the clavicle in a child who is 2 years 8 month of age (10 kg). Dotted hashes on skin surface indicate clavicle location. (B) US demonstrating access needle tip within the IJ vein using a lateral puncture approach. Note that a double wall puncture technique was avoided due to the presence of the carotid artery (A) along the back wall of the IJ vein. (Color version of figure is available online.)
the right atrium and the proximal lumen of the catheter directed medially away from the SVC sidewall (Fig. 5). The tip of a CVAC intended for infusion is positioned at the AC junction. Implantable Ports The child is positioned and IJ access is made in a similar fashion as for a tunneled catheter. Most children will have their implantable ports placed under general anesthesia due to the requirement to form a subcutaneous pocket and the associated potential discomfort. An appropriate sized im-
Figure 5 Intraprocedural fluoroscopic image demonstrating the proximal lumen (arrow) directed medially and away from the SVC sidewall during the placement of a 10-Fr dual lumen tunneled HD catheter in a 25-month-old child.
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Figure 6 (A) Skin surface outline is drawn around the intended port position using a sterile pen. This gives a good visual indication of the size required to form an appropriate port pocket. (B) An appropriate width skin incision (arrowheads) is made based on the skin surface marking to permit eventual insertion of the port device. A single clean skin incision makes suturing close the pocket easier. (C) Final fluoroscopic image upon completion of the port device insertion. Catheter tip is at the AC junction. The base of the port was positioned over the second anterior rib, but projects more cephalad in the image. The rib serves as a good base for which the port can be supported when the access needle is inserted. (Color version of figure is available online.)
Conclusions Treating and caring for children is an extremely rewarding pursuit. However, it can induce a sense of uneasiness for those IRs who do not regularly participate in the care of the pediatric patient. VIR has developed an increasing role in the placement of CVAC in children. Image guidance reduces the need for multiple punctures before obtaining successful vascular access, reducing the potential complications that can be associated.11 IRs with their expertise in the use of image guidance have an inherent skill set for the safe and reliable performance of these procedures along with the clinical acumen to advocate for vascular
preservation principles in children with chronic diseases. This article can serve as a reference for IRs who are consulted and encourages additional IRs to participate in the care of children who require central venous access.
References 1. Nosher JL, Shami MM, Siegel RL, et al: Tunneled central venous access catheter placement in the pediatric population: Comparison of radiologic and surgical results. Radiology 192:265-268, 1994 2. Connolly B, Amaral J, Walsh S, et al: Influence of arm movement on central tip location of peripherally inserted central catheters (PICCs). Pediatr Radiol 36:845-850, 2006
Pediatric central venous access 3. Darling JC, Newell SJ, Mohamdee O, et al: Central venous catheter tip in the right atrium: A risk factor for neonatal cardiac tamponade. J Perinatol 21:461-464, 2001 4. National Kidney Foundation, Dialysis Outcomes Quality Initiative: NKF-DOQI clinical practice guidelines for vascular access. Am J Kidney Dis 30:S150-S191, 1997 5. Shah PS, Shah VS: Continuous heparin infusion to prevent thrombosis and catheter occlusion in neonates with peripherally placed percutaneous central venous catheters. Cochrane Database Syst Rev 2:CD002772, 2008 6. Sayin MM, Mercan A, Koner O, et al: Internal jugular vein diameter in pediatric patients: Are the J-shaped guidewire diameters bigger than internal jugular vein? An evaluation with ultrasound. Paediatr Anaesth 18:745-751, 2008 7. Botero M, White SE, Younginer JG, et al: Effects of Trendelenburg position and positive intrathoracic pressure on internal jugular vein
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8.
9.
10.
11.
cross-sectional area in anesthetized children. J Clin Anesth 13:90-93, 2001 Janick JE, Conlon SJ, Janik JS: Percutaneous central access in patients younger than 5 years: Size does matter. J Pediatr Surg 39:1252-1256, 2004 Lorenz JM, Funaki B, Van Ha T, et al: Radiologic placement of implantable ports in pediatric patients. AJR Am J Roentgenol 176:991-994, 2001 Racadio JM, Doellman DA, Johnson ND, et al: Pediatric peripherally inserted central catheters: Complication rates related to catheter tip location. Pediatrics 107:E28, 2001 Peynircioglu B, Ozkan F, Canyigit M, et al: Radiologically placed tunneled internal jugular catheters in the management of chronic hemodialysis and long-term infusion therapies in the pediatric population. J Vasc Interv Radiol 18:875-881, 2007
T
he demand for the vascular and interventional radiology (VIR) specialty to place central venous access catheters (CVACs) in children has dramatically increased since the demonstration that image guidance enhances the safety, reliability, and cost-effectiveness of central catheter placement.1 Furthermore, as interventional radiologists (IRs) take a greater role as clinical consultants, the model is set for these providers to participate in assessing the appropriate access requirements for children in conjunction with the pediatric clinical services, as well as managing any post procedure catheter-related problems should they arise. The placement of a CVAC in infants and young children can be technically challenging, mainly because of their smaller size. Prior to initiating the process of placing a CVAC in a child, several questions should be addressed during the evaluation by the VIR service, including: (a) the indication(s); (b) catheter type and number of lumens required (for medication, total parenteral nutrition, hemodialysis [HD], etc.); (c) the expected duration of need; and (d) the appropriate location for insertion and positioning of catheter tip. With this in mind, we set out to mitigate the potential distress that may arise for the IRs who receive these consults and hope to offer a reference they can use in the care of children.
Department of Radiology, Seattle Children’s Hospital and The University of Washington, Seattle, WA. Address reprint requests to Jack-Nghia Vo, MD, Seattle Children’s Hospital and The University of Washington, Department of Radiology, Section of Pediatric Interventional Radiology, Pediatric Radiology and Vascular Interventional Radiology, 4800 Sand Point Way NE, Seattle, WA 98105. E-mail: [email protected]
250
1089-2516/10/$-see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1053/j.tvir.2010.04.003
Planning for the Placement of a Central Venous Access Catheter The most common indications for central venous access in children include the need for central venous infusion of medications, including chemotherapy, parenteral nutritional, or prolonged intravenous (IV) antibiotic course of greater than 7-10 days. Central vascular access is also required for children in need of HD/apheresis. An indication that is more common in children than adults is the need for frequent blood draws or a child with difficult peripheral venous access. Optimizing the child’s coagulation profile before performing various vascular access procedures is required. For tunneled CVAC and implantable ports, the goal for the International Normalized Ratio is ⬍1.7 with a minimum platelet count of 50,000/mm3 for a tunneled central vascular line (CVL) and 70,000/mm3 for an implantable port. Under normal circumstances, where the risk of an arterial puncture is unlikely as determined by an ultrasound (US) evaluation, the desired platelet count is ⬎25,000/mm3 for the placement of a peripherally inserted central catheter (PICC). We do not routinely require aspirin to be withheld for PICCs. Ideally, aspirin is withheld 5-7 days before placement of an implantable port or tunneled CVAC. In emergent circumstances or when the clinical condition does not permit the optimization of the coagulation parameters, we then have blood products made available and consider a non-tunneled central venous access or a PICC.
Pediatric central venous access
251
We will discuss the clinical settings in which we use various CVACs. Then we will describe our techniques and pearls for their placement in children.
routes, as the internal jugular (IJ) with its larger comparative diameter to the catheter is less prone to thrombose and occlude then a peripheral venous access site.5
Peripherally Inserted Central Catheter
Tunneled Central Venous Lines
Children with an acute illness and who require venous access of intermediate term (at least 10 days and ideally ⬍2 months but no more than 6 months) for medication infusion can be well served with a PICC. Typically, this includes children with appendicitis, septic arthritis, or osteomyelitis in whom a prolonged course of IV antibiotics is required. We also consider the placement of PICCs in children who have an acute illness and are in need of frequent or have very difficult blood draws. This is a strategy employed to minimize traumatic experiences (for both the child and parents) that can arise with repeated venous puncture attempts. We use a 3-Fr single or 4-Fr double lumen PICC catheter. The 3-Fr single lumen PICC with the tip positioned centrally at the level of the atrial caval (AC) junction (just below the inferior edge of the right main stem bronchus) is reliable for use in blood draws. The 4-Fr double lumen PICC is limited for use in children who require the simultaneous infusion of incompatible medications; the smaller individual luminal diameters make blood draws more difficult. Occasionally, in the smallest of neonates (⬍2-3 kg) who require a double lumen catheter, we will use a 2.7-Fr dual lumen PICC (Becton Dickenson, Sandy, UT). Our philosophy is to use the smallest diameter catheter that can meet the child’s needs to minimize thrombosis of the engaged vessel and the fewest required lumens to reduce the risk of infection. A note of caution for PICCs placed in the upper extremity with the child’s arm in the abducted position: When the arm is repositioned in a neutral position with the arm at side (essentially adducted) or flexed at the elbow, the tip will migrate, potentially leading to a significant change in the catheter tip position that is deeper into the chest (Fig. 1).2 This change in position is most prominent in neonates, where it can also have the greatest clinical significance. Although rare, there are several reports of fatal cardiac tamponade associated with atrial perforation from central venous catheters with the tip located in the right atrium.3 Many NICUs by policy do not allow placement of PICCs below the AC junction into the right atrium. This is in contrast to adults, in whom this is preferable. In children with congenital heart disease who are postoperative, it may be desirable to position the PICC with the tip in the subclavian vein, to avoid risk of shunt thrombosis. Communication with the pediatric cardiac services in advance may minimize malposition and the need for revision in these patients. Upper extremity PICCs (and subclavian vein CVLs) are contraindicated for children who have a history of renal insufficiency or could be anticipated to require HD in the future.4 We also limit upper extremity PICC use in children with chronic conditions that necessitate frequent and recurring venous access needs, most notably children with small bowel or solid organ transplants. Due to the expected recurrent need for venous access, using the jugular route in these children can be an effective means to preserve vascular access
We favor the use of a tunneled CVL in children when there is the need for an extended duration of venous access or an intermediate term access where an appropriate sized PICC line is not feasible or is contraindicated. Tunneled CVLs are ideal for children with chronic conditions requiring reliable extended venous access with regular use. In addition, we routinely place tunneled CVLs in children and infants in the intensive care or cardiac care units. These children are often in need of a stable and reliable central access route that is able to accommodate countless infusion sources. A tunneled CVL with a retention cuff further aids in the security of the catheter from unintentional dislodgement and reduces the risk of infection. We use a 5-Fr single or 6-Fr dual lumen Power-Line (Bard Access Systems, Salt Lake City, UT), both with a Dacron retention cuff. We try to limit these catheters to children who are at least 1 year of age and more than 10 kg in weight. The diameter of the IJ in infants less than 6 months of age and 12 kg is frequently smaller than 5 mm in diameter, and the use of a 6-Fr catheter (2-mm diameter) has a higher complication rate.6
Tunneled Hemodialysis/Apheresis Catheters Adequate flow rates are necessary for HD or apheresis catheters. Although the largest catheters will permit the greatest flow rates, the highest achievable flow rate is not absolutely necessary. We consider the catheter and patient/vessel size to achieve flow rates sufficient for reliable, timely, and adequate HD/apheresis sessions balanced with the desire to minimize complications related to the presence of the larger bore catheter within the venous lumen. Neonates and infants with their lower overall total blood volume do not need the ultrahigh flow rates commonly required for adults to complete a timely HD or apheresis session. The estimated total intravascular blood volume in children ⬍10 kg is 80 mL/kg and for those ⬎10 kg is 70 mL/kg. In children ⬍20 kg, we use the 6-Fr dual lumen Power-Line (cut to length) tunneled from the anterior chest to the IJ as access for apheresis. Children ⬍10 kg and in need of renal replacement are prepared for peritoneal dialysis. The IJ vein diameter of children 20-40 kg will typically accept an 8-Fr dual lumen tunneled and cuffed HD catheter (Medcomp, Harleysville, PA). In children who are 40-60 kg, we use a 10-Fr split lumen HD catheter (Medcomp). Children ⬎60 kg essentially have adult habitus and requirements. Under most circumstances, we favor the use of the right IJ access route. The right IJ is larger than the left in 70% of children and provides a direct path for final position of the distal catheter tip into the high right atrium to accommodate the higher flow rates and to help decrease the development of catheter tip thrombus formation, compared with those in the superior vena cava (SVC).7 In neonates with congenital cardiac anomalies who are being prepared for a cardiac trans-
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Figure 1 (A) A 2-month-old girl with mastoiditis, requiring an extended duration of IV antibiotics. Initial access was obtained with arm in the typical abducted position. The tip of the PICC catheter (arrow) appears well positioned at the level of the AC junction with the arm still in the abducted position. (B) With the arm adducted to the child’s side, the catheter tip (arrow) is now 2 vertebral body lower, into the lower right atrium. (C) Final position of the PICC catheter tip (arrow), appropriately repositioned to the AC junction with the arm in the adducted position.
plant or have had/need multistaged cardiac interventions and require access for both infusion of medication and apheresis, we place the catheter via the left IJ route. This route allows for greater intravascular catheter length and stability, decreasing the risk of complete vascular dislodgement if an unintentional event were to occur and the catheter is withdrawn several centimeters. We avoid use of the subclavian vein.8
Implantable Ports Implantable ports are ideal for children who require intermittent venous access for infusion therapy or blood draws over an extended duration. The classic candidate for a port is a pediatric oncology patient, but additional candidates include those with cystic fibrosis or thalasemias and other chronic disorders with frequent exacerbations. Mini-ports or arm
ports are preferred for their low profile in children who generally have less subcutaneous tissue. Strict adherence to guidelines for a standard surgical hand scrub and skin preparation is required for implantable ports placed in children within the interventional radiology suite.9 We routinely use antibiotic prophylaxis for skin flora coverage, 25 mg/kg (maximum 1 g) of IV cefazolin given at least 30 minutes before initiation of a skin incision.
Technique for Placement of a Central Venous Access Catheter in Children Peripherally Inserted Central Catheter The child’s arm is evaluated with US above the antecubital fossa. The arm is circumferentially prepared from the forearm to the axilla and a sterile tourniquet positioned. The arm is
Pediatric central venous access placed in the abducted position with the hand supinated. Using a high-frequency linear US probe (15 MHz vascular access probe), the target vessel is visualized and confirmed by compression and color Doppler to be venous. (A note of caution: If a tourniquet is applied too tightly in small children, the brachial artery may not demonstrate pulsatile color flow and may be compressible mimicking a venous structure. It may be necessary to release the tourniquet and reconfirm the nature of the vessel before accessing it.) After axial localization, the target vein is visualized in the longitudinal view. The access needle is advanced under real-time US visualization for direct venous puncture (Fig. 2). In the dehydrated child, the intravascular volume can be quite depleted and a bolus of additional IV maintenance fluid can aid in maximizing the diameter of the venous target (along with using the tourniquet). We use a 21-gauge long beveled percutaneous entry needle, described as a “venous bevel” by the manufacturer (Cook Medical, Bloomington, IN), as our access needle of choice. We feel that this longer bevel can more effectively pierce the frequently mobile, displaceable, and compressible vein encountered in children. Once venous entry is achieved, we use the standard Seldinger technique and advance a measuring wire under intermittent pulse fluo-
253 roscopic visualization to the AC junction. Although, a peel-away sheath (typically 0.5 Fr larger in diameter than the PICC catheter itself) is provided in most image-guided PICC sets, we find that this is not often required. After using only the inner dilator to dilate the tract, the cut-tolength catheter will frequently pass over the wire through the subcutaneous tissue into the vein with only minimal resistance. If necessary, the resistance can typically be overcome by initially permitting both the catheter and wire to be advanced simultaneously for a short distance. Once the resistance is overcome, the wire can be pinned in place as the catheter is advanced into position over the wire. We secure the catheter with a suture at the skin insertion site and an adhesive retention device for the wings. Occasionally, we will suture the wings of the PICC if the child is prone to catheter dislodgement or limited in additional venous access sites. The insertion site is covered with an antimicrobial disk at the skin entry site then covered with a clear adhesive covering. The PICC is secured after confirming appropriate catheter tip position with the arm adducted to the side.10 In circumstances in which the initial standard wire supplied with the PICC kit is not able to be advanced centrally, we will insert the dilator over the wire and perform a
Figure 2 (A) The left arm of an infant sterilely prepared circumferentially from the forearm to the axillae. A tourniquet is positioned for later use to help distend the target vein for venous entry. The hand is supinated and covered with a clear plastic drape. (B) Long view of the access needle distorting the superficial surface of vein (arrow) before venous entry. (C) US image of access needle tip (arrow) within the basilic vein upon flashback of blood at the hub. (Color version of figure is available online.)
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venogram. A 0.018 hydrophilic wire can often be manipulated beyond a stenosis or through a collateral vessel centrally. In small nonambulatory neonates when the venous structures of the arm are not sufficient or available for placement of a PICC, a tunneled femoral line may be an option. We obtain access in the femoral vein (or saphenous vein) and place the standard 3-Fr PICC catheter. When using the lower extremity for access, we will make the skin entry with the needle in the mid to upper thigh remote from the inguinal fold. This is to keep the skin entry site of the catheter away from the diaper and therefore reduce soiling and the associated increased risk of line infection. With US guidance and using the US probe as a nice spacer, away from the inguinal fold, the access needle is used to create a long shallow subcutaneous course before puncture of the common femoral vein. Alternatively, the peel-away sheath can be used to create a tunnel in the classic fashion, with the PICC fed through it to the vessel entry site. While holding the US probe with the forefinger and thumb, the fourth and fifth fingers can be used to apply compression above the inguinal fold as a method to distend and increase the diameter of the common femoral vein. Following venous entry, a standard Seldinger technique is then employed for placement of the catheter. The catheter tip is positioned at the junction of the inferior vena cava (IVC) and the right atrium (Fig. 3). Tunneled Internal Jugular Catheter A rolled towel is placed under the child’s shoulder and the head is turned to extend the neck. A high-frequency linear vascular US probe is used to localize the IJ just above the clavicle. A positive inspiratory pressure or valsalva maneuver can be used to potentially increase the cross-sectional area of the IJ in small children. A wide skin preparation is performed from the level of the auricle to below the nipple. A micropuncture needle is advanced under real-time US for direct puncture via the lateral aspect of the IJ (using either a single or, if needed, a double wall puncture technique) (Fig. 4). The 0.018 Mandril guidewire is advanced into the high right atrium under fluoroscopy. The micropuncture sheath is advanced and the wire tip is positioned for appropriate intravascular length measurement. In infants and neonates, the wire and sheath are advanced into the IVC to permit a sufficient stable intravascular component. For HD catheters, the wire is exchanged for a standard 0.035 J-tipped wire or a 75-cm Super stiff Amplatz wire (Boston Scientific, Miami, FL). The wire is positioned into the IVC to provide a stable platform for the advancement of the peel-away sheath and minimize the risk for inadvertent shearing/rupture of a central venous structure that could potentially occur if resistance is met during sheath advancement or dilation over a mobile wire. The peel-away sheath for the 5- and 6-Fr Power-Lines advance over a 0.018 wire. An appropriate position for the skin exit site is localized along the anterior chest wall. For smaller children in whom the tunneled path may need to be longer relative to the chest than typical for adults, avoid a path near the nipple. With infants and neonates, due to their small chest size, a more lateral location may need to be considered.
Figure 3 (A) Axial gray-scale US of right groin over the femoral head in a 3-kg child needing stable venous access for therapy. Common femoral artery (A) was noncompressible. Saphenofemoral vein junction (V) was compressible. (B) Image demonstrates the extended “tunneled” subcutaneous path of the access needle before entry into the femoral vein (V) overlying the femoral head (H), used to keep catheter access site remote from the diaper are and reduce the risk of infection.
Using the micropuncture needle (same needle used for IJ puncture), we anesthetize the intended tunneled tract with a premixed solution of 1% lidocaine and epinephrine mixture, 1:100,000 (Hospira, Lake Forest, IL). An appropriate length tip-to-cuff HD catheter is selected based on the measurement of the intravascular component plus the length of the tunneled tract. The Power-Lines are cut to length based on the previously measured intravascular length. We ideally position the Dacron cuff 1-2 cm above the skin exit site. After insertion of the catheter tubing through the peelaway sheath, while the child is in the Trendelenburg position, the venous entry site is gently massaged to smooth the curve of the catheter tubing in the neck. The use of a lateral venous entry approach as well as a tunneled path that approaches the venous entry site laterally aids in forming a smooth transitional curve in children and helps minimize the risk of an acute angle prone to “kink.” The lumen(s) are flushed and aspirated to assure function. With HD catheters, a 20-mL syringe is used to approximate the flow rates required. The HD catheters are positioned with the distal tip in
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255 plantable device will be selected based on the thickness and depth of subcutaneous tissue over the chest. Ideally, the skin and subcutaneous tissue overlying the port are about 5 mm in thickness. The device is placed on the skin surface over the intended pocket site and outlined with a sterile marker. This allows a good visual landmark aiding the formation of an appropriate sized pocket following adequate local anesthetic infiltration (Fig. 6). The port pocket is formed using blunt dissection mainly with a gauze-covered finger after a single continuous incision is made the width of the port device. The pocket should be made just large enough to fit the implantable device and not permit it to “flip.” We do not routinely stitch the device in place within the pocket. The catheter tubing is tunneled from the pocket and pulled out to the venotomy site and cut to the appropriate measured length. The catheter tip is positioned at the AC junction. The port pocket is closed with an interrupted deep fascial layer closure using 2-0 or 3-0 absorbable suture and 4-0 running subcuticular resorbable stitch. Alternative Access We have occasionally used transhepatic, transrenal, and direct suprarenal IVC access routes when traditional routes have been exhausted, typically in children with chronic disease states. Our goal is to avoid getting to this point. IRs involved in the care of children with chronic conditions really need to advocate early on vascular preservation principles. However, if these routes are used, considerations for respiratory motion and its relationship to the catheter must be taken into account.
Figure 4 (A) Photo showing the use of a high-frequency “hockey stick” linear US probe to localize the left internal jugular vein in the axial view just above the clavicle in a child who is 2 years 8 month of age (10 kg). Dotted hashes on skin surface indicate clavicle location. (B) US demonstrating access needle tip within the IJ vein using a lateral puncture approach. Note that a double wall puncture technique was avoided due to the presence of the carotid artery (A) along the back wall of the IJ vein. (Color version of figure is available online.)
the right atrium and the proximal lumen of the catheter directed medially away from the SVC sidewall (Fig. 5). The tip of a CVAC intended for infusion is positioned at the AC junction. Implantable Ports The child is positioned and IJ access is made in a similar fashion as for a tunneled catheter. Most children will have their implantable ports placed under general anesthesia due to the requirement to form a subcutaneous pocket and the associated potential discomfort. An appropriate sized im-
Figure 5 Intraprocedural fluoroscopic image demonstrating the proximal lumen (arrow) directed medially and away from the SVC sidewall during the placement of a 10-Fr dual lumen tunneled HD catheter in a 25-month-old child.
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Figure 6 (A) Skin surface outline is drawn around the intended port position using a sterile pen. This gives a good visual indication of the size required to form an appropriate port pocket. (B) An appropriate width skin incision (arrowheads) is made based on the skin surface marking to permit eventual insertion of the port device. A single clean skin incision makes suturing close the pocket easier. (C) Final fluoroscopic image upon completion of the port device insertion. Catheter tip is at the AC junction. The base of the port was positioned over the second anterior rib, but projects more cephalad in the image. The rib serves as a good base for which the port can be supported when the access needle is inserted. (Color version of figure is available online.)
Conclusions Treating and caring for children is an extremely rewarding pursuit. However, it can induce a sense of uneasiness for those IRs who do not regularly participate in the care of the pediatric patient. VIR has developed an increasing role in the placement of CVAC in children. Image guidance reduces the need for multiple punctures before obtaining successful vascular access, reducing the potential complications that can be associated.11 IRs with their expertise in the use of image guidance have an inherent skill set for the safe and reliable performance of these procedures along with the clinical acumen to advocate for vascular
preservation principles in children with chronic diseases. This article can serve as a reference for IRs who are consulted and encourages additional IRs to participate in the care of children who require central venous access.
References 1. Nosher JL, Shami MM, Siegel RL, et al: Tunneled central venous access catheter placement in the pediatric population: Comparison of radiologic and surgical results. Radiology 192:265-268, 1994 2. Connolly B, Amaral J, Walsh S, et al: Influence of arm movement on central tip location of peripherally inserted central catheters (PICCs). Pediatr Radiol 36:845-850, 2006
Pediatric central venous access 3. Darling JC, Newell SJ, Mohamdee O, et al: Central venous catheter tip in the right atrium: A risk factor for neonatal cardiac tamponade. J Perinatol 21:461-464, 2001 4. National Kidney Foundation, Dialysis Outcomes Quality Initiative: NKF-DOQI clinical practice guidelines for vascular access. Am J Kidney Dis 30:S150-S191, 1997 5. Shah PS, Shah VS: Continuous heparin infusion to prevent thrombosis and catheter occlusion in neonates with peripherally placed percutaneous central venous catheters. Cochrane Database Syst Rev 2:CD002772, 2008 6. Sayin MM, Mercan A, Koner O, et al: Internal jugular vein diameter in pediatric patients: Are the J-shaped guidewire diameters bigger than internal jugular vein? An evaluation with ultrasound. Paediatr Anaesth 18:745-751, 2008 7. Botero M, White SE, Younginer JG, et al: Effects of Trendelenburg position and positive intrathoracic pressure on internal jugular vein
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cross-sectional area in anesthetized children. J Clin Anesth 13:90-93, 2001 Janick JE, Conlon SJ, Janik JS: Percutaneous central access in patients younger than 5 years: Size does matter. J Pediatr Surg 39:1252-1256, 2004 Lorenz JM, Funaki B, Van Ha T, et al: Radiologic placement of implantable ports in pediatric patients. AJR Am J Roentgenol 176:991-994, 2001 Racadio JM, Doellman DA, Johnson ND, et al: Pediatric peripherally inserted central catheters: Complication rates related to catheter tip location. Pediatrics 107:E28, 2001 Peynircioglu B, Ozkan F, Canyigit M, et al: Radiologically placed tunneled internal jugular catheters in the management of chronic hemodialysis and long-term infusion therapies in the pediatric population. J Vasc Interv Radiol 18:875-881, 2007