Central venous catheter

The central venous catheter ( CVC; Synonyms: central venous catheter, central venous catheter, central venous access ) is a thin plastic tube that is inserted through a vein of the upper half of the body into the venous system and the end of which lies in the upper or lower vena cava before the right atrium of the heart.

In contrast to a CVC peripheral venous catheters allows the feeding of highly concentrated electrolyte and nutrient solutions, and the measurement of the central venous pressure ( CVP) as a guide for the intravascular volume ( blood volume = ). Since the system of a central venous catheter complicated and complication -prone than that of a peripheral catheter, requires a clear indication for this intervention.

A central venous catheter is not to be confused with a Swan -Ganz catheter, which is advanced by a central vein to the right atrium, then through the right ventricle into the pulmonary artery. He comes pulmonary to lie behind the right atrium and the right ventricle in the trunk of the artery.

Indications and contraindications

For a central venous catheter, the system there are a number of indications:

• Infusion of solutions and drugs that are highly irritating to veins ( higher doses of sodium bicarbonate, potassium chloride and high-calorie glucose or amino acid infusions in particular in the context of a parenteral nutrition)
• Infusion of circulatory and cardioactive drugs with short half-life ( catecholamines )
• Inability of the installation of a peripheral infusion access, for example in shock (especially volume deficiency shock and septic shock), with extensive burns, with hypothermia or long lasting infusion therapies with recurrent puncture of peripheral veins
• Measurement of central venous pressure
• Massive transfusions
• OP with a risk of air embolism ( air accumulations in the right heart can be drawn off via CVAD)

Relative contraindications are anatomical malformations due to the risk of failed punctures, blood clotting disorders because of the risk of extensive bruising, severe chronic and acute lung diseases in which there is a risk of pneumothorax and allergy of the patient on the CVC materials.

However, since the construction of a central venous catheter is anyway usually performed only in very ill patients, such an investment may be carried out by risk - benefit analysis in the presence of these relative contraindications.

CVCs are available with up to six Lumina. The most common two- and triple-lumen variants are selected. It can then, for example, single lumen parenteral nutrition, catecholamines and antibiotics run in parallel, without the risk of incompatibility between the individual substances. However, with increasing number of lumens increases the risk of infection, so that the indication for more lumens should be strictly provided.

Access paths for the CVC

• Preferred access routes Internal jugular vein in the neck
• Subclavian vein under the collarbone

• Basilic vein in the arm
• Innominate vein in the neck syn. brachiocephalic vein

• External cephalic vein antecubital
• Brachial vein inside antecubital
• External jugular vein
• Femoral vein in the groin

The preferred access route should be on the side of the neck the internal jugular vein. Here is the vein easy to find on the basis of anatomical landmarks and sonographically well represent. There also is a large, fixed behind muscles and almost always open while lying vein. The right-sided puncture should if possible be preferred, since the vein is easier to meet here because of its course and opens out on the opposite side thoracic duct can not be violated.

There is a risk to puncture failed punctures in the common carotid artery (but this can be minimized under sonographic view). This can lead to thrombus formation in the carotid artery supplying the brain with thromboembolism in vessels and thus to an apoplectic insult ( stroke). Even an acute occlusion of the carotid artery by thrombus formation can lead to a stroke.

As an alternative, the subclavian vein offers below the collarbone. Advantages are clear anatomical orientation and often quickly possible investment. Especially with a lack of volume, this approach is advantageous because this vein is clamped between the clavicle and the first rib and thus always unfolds ( the internal jugular vein collapses and can not be punctured ). The distance from the passage through the skin until it enters the vein is relatively long, which is an infection barrier. Subclavian catheters can therefore be left mostly longer before a Katheterseptikämie occurs. Most patients find the subclavian catheter as less disturbing than the exiting the neck internal jugular catheter. Major disadvantages are the risk of pneumothorax in case of accidental puncture of the lung apex and only difficult to control bleeding into the skin and into the chest, as the vena is inaccessible subclavian compression from the outside. Failed punctures of the subclavian artery are quite common, stay for the patients, however, usually without adverse consequences. Because of the risk of pneumothorax may be punctured in unilateral lung disease never the healthy side. For the same reason a new puncture on the opposite side is to be executed at erroneous puncture.

In some circumstances, access via the external jugular vein - unless it is clearly visible from the outside - represent a technically simple alternative, but with frequent dislocations connected (eg, kinking of the catheter into veins or other cranially ).

Puncture of the arm veins is not always possible, though overall complications. Also, the catheter may not always be pushed far enough in particular for puncturing the cephalic vein. Due to the long catheter complications such as phlebitis or thrombosis of the arm veins are more common, so that a Armvenenkatheter usually only a few days can be left.

The femoral vein in the groin is a technically quite simple to be punctured vascular access represents a defined here catheter is associated with a risk of thrombosis of the leg veins. Also, lesions of the femoral nerve are possible. From a hygienic point of view (strong colonization of the groin with aerobic and anaerobic bacteria), a puncture of the femoral vein is more decline. Mainly because of the first-mentioned complication itself, this approach is not suitable for longer, leaving the catheter so that the femoral vein should only be selected for the puncture, when other puncture sites do not come into question, or at most for a transient system, to below may be improved initial conditions a catheter in the jugular vein or subclavian vein can be placed. One in the femoral vein lying catheter should not be called a central venous catheter, since it does not meet the conditions for this. He is not a measurement of central venous and central venous pressure is not possible here. So he should be referred to in the V.femoralis only as " venous access with a large lumen ."

Implementation

First, the puncture region is inspected, possibly with the use of ultrasound. When Jugularispunktion now made the head-down storage, for better filling of the vein and to protect against aspiration of air. After a local anesthetic and disinfection is carried out.

The puncture in sterile technique occurs either blind to the knowledge of anatomy, or under ultrasound guidance. The catheter is usually inserted with the aid of the Seldinger technique. But there are also direct puncture kits on the market. Their advantage is the faster system without guide wire, the disadvantage in the vein puncture with a large-bore cannula through which the catheter is inserted directly.

Well, if so, a position control are performed by means of atrial ECG. About using a marker withdrawn exactly at the CVC tip Seldinger wire a monitor ECG is recorded. In the vicinity of the right atrium, there is a pointed elevation of the P wave, the normalized upon withdrawal of the catheter again, so that the correct position can be adjusted.

Thereafter, a Aspirationskontrolle and flushing of the catheter. The CVC is usually fixed by retaining clip and suture. Finally, a sterile bandage is applied. A chest X-ray is the final position control and the exclusion of a pneumothorax.

Complications

When lying central venous catheter is a risk of various complications. These include the formation of haematomas after miscarriage puncture or perforation of the vein, rare of an artery or the injury of adjacent nerves, a malposition of the central venous catheter ( with Herzrhymusstörungen with intracardiac location ) and a pneumothorax, also known as acute life-threatening tension pneumothorax, in violation of the pleura.

A colonization by bacteria or fungi leads to the so-called central venous catheter - associated bacteremia or fungemia and often to a - in the Anglo- Saxon world as catheter -related bloodstream infection ( CRBSI ) designated - catheter sepsis, at the in 1994, 15-25 % of patients died. The incidence figures for a catheter-related sepsis in the European Union were given as 1.55 per 1,000 CVC - days sun.

By introduction of air into the venous system is a risk of air embolism. Thrombosis and thrombophlebitis are further complications.