One of the more common operations performed by pediatric surgeons is placement of lines for vascular access. Put simply, this means placing a tube in a vein so that medications can be repeatedly delivered directly into the bloodstream. Infants and children have small veins that are often difficult and painful to enter. Sometimes the medications or solutions that are given are damaging to the vein wall, so they are better tolerated if infused into larger veins.
Patients referred for vascular access have a wide variety of diagnoses and are referred by many different types of medical specialists. The most common situation requiring vascular access is chemotherapy for treatment of cancer. Other common indications include intravenous nutrition, renal failure requiring hemodialysis, and blood diseases like hemophilia.
The decision of which type of vascular access to place is based on several factors, including duration of the need for access, frequency of access, and the patient’s venous anatomy. There are three main types of devices used:
These catheters are usually placed into the large veins above the heart (superior vena cava). The ideal position for the tip of the catheter is the junction of the right atrium and the superior vena cava. They typically enter the central venous system via the neck (internal jugular) or upper chest under the collar bone (subclavian) and are then tunneled to a separate exit site.
External tunneled catheters are designed with a fuzzy cuff of Dacron bonded to the catheter that is positioned in the tunnel. This cuff serves two functions:
Provides a barrier to migration of bacteria along the catheter. This lowers the risk of infection.
Helps to secure the catheter by tissue ingrowth into the cuff. This helps prevent accidental dislodgement.
These catheters are available in various sizes from 2.7 French to 13.5 French. (See French catheter scale.) They may have one, two, or even three lumens (openings). They are referred to by multiple names (e.g. Broviac, Hickman, Groshong, Permacath, Quinton). External tunneled catheters can be accessed frequently (daily, hourly, even continuously) but have a slightly higher rate of infection than ports.
Implantable ports consist of an enclosed well with a silicon top that can be penetrated with a special needle. The attached catheter is positioned in a central vein, as with a tunneled external catheter. Because the entire device is placed under the skin, access requires a needle stick but it is usually well tolerated after application of a topical anesthesia cream. In general, these ports are best suited to intermittent use (e.g., weekly), since repeated skin puncture can lead to skin breakdown and increased infections. The advantage of ports, as compared to external catheters, is the reduced incidence of infection. Also, the buried status allows normal bathing, swimming, etc.
Peripherally inserted central catheters are smaller, longer lines that are inserted through a peripheral vein (usually in the arm) and carefully threaded into the central veins near the heart. PICCs range in size from 2 French to 5 French. hey can be single or double lumen. The advantage is the simpler insertion. Sometimes they can be inserted on the ward with local anesthesia.
|External Tunneled Catheter||Months-Years||Daily, hourly||Moderate||+++|
After placement, most catheters/ports are well tolerated. The most frequent complications are infection and obstruction.
The incidence of catheter infection is correlated with the patient’s diagnosis. For example, patients receiving chemotherapy often have low white blood cell counts and are more susceptible to line infections.
Obstruction can occur from clotted blood in the catheter or precipitation of medications (especially lipids or calcium). Sometimes clots can be dissolved with thrombolytic therapy to clear the catheter and avoid the need for replacement. Equally problematic is thrombosis of the vein in which the catheter resides. (Thrombosis refers to the formation of a blood clot inside a blood vessel.) Thrombosis of the great vessels in the chest may require anticoagulation and catheter removal.
This information is provided by the Department of Surgery at the University of Colorado School of Medicine. It is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition.