All About Ports
Medical Ports- Central Access Venous Devices (CVADs)
(Information Below Provided by the National Hemophilia Foundation)
Central venous access devices (CVADs), often called medical ports, have become an important tool in the management of hemophilia in many children. Treatment methods for patients with hemophilia now include prophylactic or immune tolerance regimens that require frequent regular infusions of clotting factor concentrate, often beginning at an early age. When such regimens are undertaken, CVADs can be utilized to facilitate venous access.
Prophylactic therapy, especially in the young child with hemophilia, has led to increased utilization of CVADs. The most common of these devices are subcutaneously implanted Ports. These devices have potential risks as well as benefits that should be considered on an individual basis and adequately discussed with physicians so that families will have a clearer understanding of the intensity of care required by patient/families, potential complications, and situations requiring contact with a medical care provider. The decision as to which CVAD is recommended for any particular patient is based upon a variety of factors including the patient's clinical circumstances, specific needs, past history with these devices, age and size, as well as the experience and comfort level of the treatment center personnel and surgeon with these devices.
Two clear benefits of CVADs in patients with hemophilia are the ease of access and administration of replacement therapies to treat or prevent bleeding episodes and the reduction of long-term damage to peripheral veins. The use of CVADs has increased patient and family freedom from the need for immediate access to medical care. CVADs have decreased the fear of pain associated with venipuncture in children and decreased the need for visits to physicians, emergency rooms, and treatment centers for infusion therapy. The majority of patients and families can be taught appropriate care of these devices to provide a safe level of care at home.
There are many potential risks associated with the use of CVADs; chief among them are infection and thrombosis.
CVADs are foreign bodies that may become infected. Infection may arise due to inadequate sterile technique when accessing the device, but may also arise in face of appropriate sterile technique. Infections of CVADs are potentially serious and in some instances life threatening, as these devices are in direct communication with the blood supply and may lead to rapid growth of bacteria and overwhelming infection in the patient. The frequency of occurrence of line sepsis varies as reported in different publications depending upon the center and method of calculation. Calculated based upon the number of catheter days, the infection rate for Ports is approximately 0.4/1000 catheter days (1). If infection rates are calculated as a percentage of the population of all patients with Ports, the reported rate varies from 8-55% (2-5). Infections appear to be more common in children less than 2 years of age, children with inhibitors, children with a history of previous CVAD infection or thrombosis, and children whose lines have to be accessed frequently. Other risk factors for infection include poor oral hygiene and presence of dental cavities and/or abscesses. CVADs with more than one lumen have an increased risk of infection, at least in externalized lines. Some medical conditions are associated with an increased risk of infection, including those with immune system compromise such as HIV. Recurrent infections in one device should trigger a follow-up investigation of risk factors in the patient and discussion with the care provider about sterile techniques and ways to minimize further infection.
Thrombosis is the development of a clot in a blood vessel that may obstruct or occlude blood flow. Patients with hemophilia may develop blood clots despite their underlying bleeding disorder, especially in association with the use of CVADs. A clot may develop within the line or device itself, which is often treated with medications that dissolve clots. If the clot within the device cannot be dissolved, then the device may need to be removed and/or replaced. A clot that occurs within a blood vessel may also lead to removal of the device based upon the symptoms the patient has experienced, the extent of the clot, and the function of the line. Not all devices are replaced with another CVAD after a significant clot in the blood vessels has occurred. For example, some patients may develop extensive clots in the upper body venous system leading to arm and face swelling due to poor venous return. The long-term risks and consequences of thrombosis related to CVADs in hemophilic children are not currently known.
Other risks associated with CVADs include:
- Line fracture and migration of the catheter into another area of the body, usually the heart or lungs.
- Separation of the catheter from the reservoir of the CVAD leading to no blood return and infiltration of the infused material into the tissues surrounding the device.
- Development of a hematoma (bruise or bleed) around the reservoir where the device is accessed.
- Opening of the skin over the device exposing the CVAD, usually occurring over the reservoir. This is called dehiscence.
- Leakage of the material injected or infused into the CVAD into the tissues surrounding the device if the needle is not correctly positioned.
- Development of a tear in the material covering the reservoir, usually due to the use of improper needles for access.