Central Venous Access Devices

In industrialized countries the use of central venous access devices is a common occurrence in hospitals, the home and retirement facilities. Many types of such devices are available. They are essentially used to give intra venous medications, obtain venous samples of blood and obtain measurements of central venous pressure. The main advantage of using these devices is that large volumes of fluids and medications can be administered quickly and safely both in the hospital and home settings.

Three of the most commonly used devices are the Porta cath, PIC catheter and the central venous catheter. Both the Porta cath and the PIC catheter have a single lumen only. The central venous catheter may have single or multiple lumen. The CVP catheter and the PIC catheters are usually inserted in the Juglar or Subclavian veins. Sometimes, the Femoral vein may be used.

Prior to insertion of one of these devices, informed, signed consent is routinely obtained from the patient. In some emergency situations this may be waived at the discretion of the treatment team. The purpose, the possible complications and potential benefits of these devices are explained to the patient. If the patient is a minor then the procedure is also explained to the parents. In elderly patients who cannot understand the procedure it is important to get the consent of the legal guardian or next of kin.

The thin end of the porta cath is inserted into the subclavian vein in aseptic conditions, usually in the operating theater. The dome is buried under the skin and is usually palpable just below the surface of the skin. At the point of insertion a scar may be visible. This type of catheter requires the least amount of maintenance because it is under the skin. All medications which are prescribed via this route can be given by cleaning the skin and injecting the medication into the dome, after palpating it. The injection site should be rotated so that skin healing takes place between injections.

It is routine to have an x-ray to insure that the catheter is in correct site.

Once the external wound has healed there is no routine maintenance.

Multi lumen catheters are commonly used in the hospital setting to give medications, obtain venous specimen of blood, measure central venous pressures and to obtain core temperature accurately. Central Venous catheters are inserted via the external jugular or subclavian veins. This procedure is usually done in the intensive care unit or the operating theater but can also be performed reasonably safely in the ward. A portable chest x-ray must be done to check placement prior to commencement of fluid and medication administration. The ports are color coded and each port has a different use.

The advantage of this type of catheter is that many medications and blood can be administered at the same time. Of course different ports are used for different. Pre and post flushing is commonly done when incompatible medications are used.

The tip of the multi lumen catheter is usually outside the right auricle auricle of the heart where the superior and inferior vena cava meet. This is the best site for measuring the central venous pressure. The generally accepted normal value for the CVP is from +5 cms of water to + 10 cms of water.

It is not unusual for this catheter to be sutured in place because the many lines may pull in different directions. If it is not sutured then it is important that a sandwich dressing is applied to keep the CVP catheter anchored in.

Both the PICC and the CVP catheters can be a source of infection. Generally, it is the patients skin bacteria which grow along the catheter and infect the patients blood. When this happens then it may be necessary to remove the catheter and insert a new one.

CVP Cath. Dressings and PIC Cath. Dressing are routinely changed every day or every other day.

When injecting into the catheters it is important to clean the external bung or hub depending upon the type of device used in your facility.

Only duly authorized doctors, nurses, grade 2s and enrolled nurses should administer medications via these devices. When an institution has a policy or protocol then it must be followed.

The insertion of this type of catheter is generally done on the ward. In some situations the surgeon may do it in the operating theater following other surgery. Informed consent is a standard with all invasive and non-invasive medical / surgical procedures.

The external dressings are usually done every other day and the catheter is flushed after medication administration. If the catheters are not flushed either with normal saline solution or with saline and heparin they will “clot” and become unusable. If this happens with a multilumen port then simply label that port as occluded and do not use it. If this happens with a single lumen catheter the catheter will need to be removed and a new one inserted.

Excessive force should never be used to unblock an “occluded” catheter because the “clot” will enter the patients venous system and cause blockage at the narrowest capillary network which will obviously be in the Pulmonary Circulation.

Risks associated with venous access devices include phlebitis, inflammation, pain, air embolus, local sensitivity, and psychological stress. Infection is the most common complication.

Pictures of these devices (three) will be added to the publication in due course.

Other nursing articles by this author (Shergill) can be found at Triond.com .

Sarjeet S. Gill. RN., BSc., MBA., PGCE. Specialist Certificates in Oncology, Intensive Care and Psychiatric Nursing.