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Vascular Access in Children 51

• Has a plastic area where clamps can be applied. The two main advantages of Port-a-Cath catheters are that no part
of the catheter is exposed, so the infection rate is low, and that catheter
• Has connectors.
displacement and venous occlusion are uncommon. Other advantages
• Costs about US$135 (100 euros) each. are that the catheter requires flushing only every 5–6 weeks, regular
dressing is not required after the incision has healed, and the patient
Broviac catheters
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Long-term, tunneled catheters have been available since 1968. In 1973, can bathe or swim. The Port-a-Cath can be used for brief general
anaesthesia (e.g., lumbar puncture).
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Broviac made the first important improvement to the design by pro- The two main disadvantages of these catheters are that insertion is
ducing a catheter with an internal diameter of 1.0 mm, which facilitates time-consuming and that general anaesthesia is necessary for insertion
repeated blood sampling.
and removal. Another disadvantage is that the assessing needles have
Hickman catheters fine bores, so blood transfusion is slow. These catheters are very costly,
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Robert Hickman, a paediatric nephrologist at the Seattle Children’s at about US$675–1350 (500–1000 euros) each.
Hospital, modified the Broviac catheter with subcutaneous tunneling Peripherally Inserted Central Catheters
and a Dacron cuff that forms an infection barrier. Broviac and Hickman
Peripherally inserted central catheters (PICC) are fine-bore soft cath-
catheters are open-ended and can be cut to the desired length. The major
eters that are passed from cubital veins up the axillary vein into a
difference between the Broviac and the Hickman is the internal diam-
central vein. They are used as alternatives to Hickman catheters. They
eter: the Broviac is 1.0 mm, and the Hickman is 1.6 mm.
generally have higher rates of phlebitis, occlusion, and thrombosis than
Groshong catheters tunneled catheters.
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The Groshong catheter has a design similar to the Hickman but has a Surgical Techniques
formed blunt end with a slit-like orifice just proximal to the distal end.
This acts like a valve, which stops back-bleeding, prevents air entry Insertion of central venous catheter in emergency situations
and embolism from negative intrathoracic pressure, and obviates the To be considered a central line, the tip of the catheter must be located in
need for a heparin lock because saline can be used instead. An exter- the vena cava, subclavian, brachiocephalic, innominate, or iliac veins.
nal clamp, which may damage the catheter, is therefore unnecessary. The safest technique for insertion of a CVC via the transcutaneous
Groshong catheters cannot be used to monitor central venous pressure route into the internal jugular vein, subclavian, or femoral vein is by the
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due to the valve function. The valves may, however, produce intermit- Seldinger method. Complete catheter sets, including aspiration needle,
tent boluses of fluid or drugs, which may make these catheters unsuit- guidewire, dilatator, peel-away sheath, and polyurethane catheter, are
able for inotropic or vasopressor infusion. available as packs from several companies. In young children, the
The advantages of Groshong catheters are that they are flexible procedure is best performed under general anaesthesia, but in older or
and the insertion site is removed from the exit site. These assist in the very sick patients, the site can be infiltrated with local anaesthetics. The
prevention of systemic infection. Once the tissue adheres to the Dacron veins are easier to cannulate by using ultrasound guidance.
cuff, another barrier to infection is created. The secured cuff also Important steps in inserting a central venous line are listed below.
prevents catheter dislodgment. These are essentially the steps in the Seldinger technique:
The main disadvantages of Groshong catheters are that, being 1. Explain the procedure (including possible complications) to the patient.
outside the body, they provide vehicles for infection. They also require 2. Have the patient or parent sign a consent form.
frequent flushes and dressing changes. There are also limitations for
swimming and bathing. The catheters are not suitable for dialysis as 3. Get all necessary equipment—port, catheter, saline, syringes,
they are not designed for high-flow blood withdrawals. heparin solutions, etc.
4. Scrub and down surgical gown and gloves (an assistant may be necessary).
Port-a-Cath ®
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Port-a-Cath catheters are silicon catheters connected to self-sealing 5. Open the port and catheter and flush with heparinised saline. Make
sure all connections are working properly.
injection ports that are completely inserted under the skin. The intra-
vascular segment is similar to the Hickman catheter. The port is a small 6. Prep the patient with povidone iodine and drape the required field.
metal, plastic, or titanium “drum” or reservoir that has a membrane 7. Identify the landmarks and infiltrate the required area with local
through which the vein can be accessed by using a special Huber-type anaesthetic.
needle. Suture holes in the base of the port are anchored to fascia layers
8. Place the patient in the Trendelenburg position.
with nonabsorbable sutures.
9. Insert an 18-gauge (20G for infants) needle into the chosen vein
The Port-a-Cath catheter has the following features:
until blood is freely aspirated (ultrasonic guidance may be helpful).
• lightweight, durable titanium portal reservoir, which provides gouge
resistance and long-term durability; 10. Remove the syringe while retaining the needle.
11. Insert the J-shaped end of the guide wire into the needle (check the
• contoured shape, designed for patient comfort and ease of portal
palpation; position with fluoroscopy, if available).
12. Remove the needle.
• needle-stop titanium reservoir floor, which creates positive tactile
feedback when the accessing needle makes contact; 13. Advance the dilatator over the guide wire and remove the dilatator.
14. Insert the catheter over the guide wire.
• distinct rounded septum ring, designed to assist in septum location;
15. Suture the catheter in place.
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• high compression SECUR SITE septum captured in titanium,
16. If a port is needed, dissect the subcutaneous tissue with mosquito
designed for needle retention and stability;
artery forceps and bluntly with finger to accommodate the port.
• bevelled suture holes, designed for ease of suturing;
17. Flush all ports with heparinised saline.
• ULTRA-LOCK catheter connector integrated with portal, for ease 18. Give the patient intravenous antibiotics.
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of system assembly; and
19. Take a chest x-ray to confirm the final position and rule-out
• magnetic resonance imaging (MRI)-compatible portal systems. pneumothorax.