Central venous access procedures form a large part of the workload in pediatric interventional radiology, comprising nearly 50% of the cases in our practice.¹ The ability to provide routine venous access both for the administration of medication and for diagnostic blood sampling has become a basic requirement in the acute medical care of the child. The major indications for central venous access in children include total parenteral nutrition, prolonged intravenous therapy, use of toxic chemotherapies, difficult access, frequent blood transfusions or sampling and hemodialysis.

The following types of device are used:

• PICC: peripherally inserted central venous catheters are often used for toxic therapies, long-term antibiotics and total parenteral nutrition. They are unsuitable if high infusion rates are necessary.

• Tunneled catheters (e.g. Hickman or Broviac catheters) pass through a subcutaneous tunnel before entering a central vein. They can have more than one lumen, and are intended for long-term use.

• Ports (e.g. Port-a-Cath) are subcutaneously implanted reservoirs attached to central venous catheters. They are intended for long-term intermittent use.

We check full blood count and coagulation profiles in all children with chronic systemic or severe acute disease before the procedure. Uncorrected coagulopathy and more than moderate thrombocytopenia (platelet count <50 μL⁻¹) are relative contraindications to central line insertion.

It is sometimes necessary to insert a central venous access device in a child with positive blood cultures, but this should be avoided where possible.

The selection of catheter to be inserted depends on several factors:

• intended duration of use

• type of infusion and frequency with which it will be infused

• venous anatomy and access sites

• previous intervention at the intended site for access and future needs for access

• clinical history and coagulation status

• preference of the physician or patient

• ability of the patient or carers to maintain the device.

The use of ultrasound guidance makes central venous access easy, quick and safe in all but the most difficult cases. Potential advantages over surgical placement of central lines include a very high success rate at the first site attempted, a good cosmetic result because of the short puncture site incision, a short procedure time and no need for preoperative imaging in children who have had multiple central veins accessed in the past.¹ Table 13.1 lists, for various veins, indications for access.

Table 13.1 Ultrasound-guided venous access

Access	Common indications	Other indications
Internal jugular veins	Central venous catheterization	Transjugular liver biopsy TIPS IVC filter insertion Other venous intervention
Subclavian veins	Central venous catheterization	Pacemaker insertion
Femoral veins	Central venous catheterization	Venous sampling Transvenous biopsy IVC filter insertion Other venous intervention
Upper limb veins	PICC insertion	Other venous intervention
Hepatic veins	Cardiac intervention	Central venous catheterization
Portal venous system	Pancreatic venous sampling	Islet cell infusion Portal vein embolization

IVC, inferior vena cava; PICC, peripherally inserted central venous catheter; TIPS, transjugular intrahepatic portosystemic shunt.

Technique

A high-frequency linear array probe is used for most procedures. The puncture can be performed with the needle either parallel to or perpendicular to the long axis of the probe. A 21-gauge needle (which accepts a 0.018-inch guidewire) is usually used in small children. In older children it is possible to use 19- and 18-gauge needles (which accept 0.035- and 0.038-inch guidewires, respectively). Non-tunneled catheters can be inserted over the guidewire following dilation of the tract with a vascular dilator. The insertion of tunneled catheters requires the use of a peel-away sheath (Fig. 13.1).

Figure 13.1 Catheters used for central venous access. (A) Dual lumen PICC line. (B) Single lumen Hickman line. (C) Port device.

The standard method for central venous catheter insertion can be seen from the procedure for insertion of an internal jugular Hickman catheter. The patient’s skin is prepared and draped in a standard fashion. The puncture and exit sites are identified, and bupivacaine 0.25% is injected at and between these sites. Stab incisions are made, and the catheter is tunneled through the subcutaneous tissue between them using a tunneling probe. The puncture needle is inserted through the puncture site incision, taking care not to damage the catheter. It is important to puncture the vein with a sharp, stabbing motion to ensure that the tip of the needle enters the lumen of the vein. The needle should be seen to move freely in the lumen, without a ‘tent’ of intima over the tip. It is easy to advance the guidewire along a subintimal plane if care is not taken at this stage. Inadvertent puncture of the opposite wall of the vein is usually not a problem. The guidewire is then advanced into the vein in a central direction, and its position confirmed by fluoroscopy. If it is easy to pass the guidewire through the right atrium and down the inferior vena cava, this should be done, as it makes insertion of the peel-away sheath easier. Following removal of the needle, the peel-away sheath is advanced over the guidewire. It is crucial to fix the guidewire (relative to the patient) at this stage. If this is not done, the dilator of the peel-away sheath may cause serious damage to the superior vena cava or heart. I suspect that the occasional reports of cardiac tamponade following Hickman insertion are due to injury occurring at this stage. The next step is to cut the catheter to the desired length. In many centers, the catheter tip is left in the superior vena cava, although this appears to be associated with an increased risk of superior vena cava thrombosis. We prefer to leave the tip in the right atrium. Fluoroscopy can be performed with the catheter on the anterior chest wall, projected over the peel-away sheath. If the catheter is then cut at the T7 level, its tip will lie in the upper right atrium. The guidewire and the dilator of the peel-away sheath are removed, and the catheter advanced through the sheath. The sheath is then split and removed. The position of the catheter tip is confirmed with fluoroscopy. The catheter is flushed with heparin (10 units/ml) and sutured to the skin at the exit site. The puncture site can be closed with a subcuticular suture, tissue glue or adhesive tape.

Venous access sites

The most frequently used central veins are the internal jugulars, subclavians and femorals. The right internal jugular vein (Fig. 13.2) is usually the preferred site for insertion of temporary and tunneled central venous catheters and venous port devices. When this vein cannot be used, the left internal jugular vein is preferred to the subclavian veins. This advice is not evidence-based but relies on the assumption that the risks of pneumothorax and inadvertent arterial puncture are less with ultrasound-guided jugular puncture.