25: Central Venous Catheterization and Pressure Monitoring

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CHAPTER 25 Central Venous Catheterization and Pressure Monitoring

Lyle E. Kirson, DDS, Jacob Friedman, MD

1 Define central venous catheterization

Central venous catheterization involves inserting a catheter into the venous circulation and advancing it so its distal orifice is positioned immediately adjacent to or within the right atrium of the heart (Figure 25-1).

Figure 25-1 Placement of the central venous catheter.

3 What are the nonoperative indications for placement of a central venous catheter?

Hyperalimentation

Temporary hemodialysis

Long-term chemotherapy

Frequent therapeutic plasmapheresis

4 What is the best approach to central venous cannulation?

Numerous access points are available for introduction of a catheter into the venous circulation. All approaches carry risks, and none will work successfully for every patient. Therefore it is important to become familiar with several approaches: subclavian vein, internal jugular vein, antecubital external jugular vein, and femoral vein. It is also of interest that peripheral venous pressure when measured at the antecubital vein closely mirrors the central venous pressure (CVP).

5 Describe the subclavian vein approach

The subclavian approach is commonly used because of the ease of access to the vessel. The subclavian vein is best cannulated from the subclavicular approach with the patient in the Trendelenburg position. The skin puncture is made just lateral to, and one fingerbreadth below, the costoclavicular ligament, which can be identified by a notch two thirds of the length down the clavicle. The needle is directed along the posterior border of the clavicle in the direction of the sternal notch until venous blood is aspirated.

6 Describe the internal jugular vein approach

There are several approaches to the internal jugular vein, three of which are briefly described here. The patient is put in the Trendelenburg position.

Low anterior: Locate the point at which the sternal and clavicular heads of the sternocleidomastoid muscle join. Introduce the needle at this point and direct it at a 30-degree angle to the skin. Advance the needle toward the ipsilateral nipple until venous blood is aspirated.

High anterior: Palpate the carotid artery at the level of the cricothyroid membrane. Introduce the needle just lateral to the carotid pulsation and advance it toward the ipsilateral nipple at a 30-degree angle until venous blood is aspirated. This approach frequently requires penetration of the sternocleidomastoid muscle by the introducer needle.

Posterior: Locate the junction of the posterior border of the sternocleidomastoid muscle and the external jugular vein. Introduce the needle just posterior to this point and advance it along the deep surface of the muscle toward the ipsilateral corner of the sternal notch until venous blood is aspirated.

7 Describe the external jugular vein approach

When the patient is in a Trendelenburg position, the external jugular vein frequently can be visualized where it crosses the sternocleidomastoid muscle. The needle is advanced in a direction paralleling the vessel and is introduced into the vein approximately two finger widths below the inferior border of the mandible. Difficulty may arise in advancing the catheter or guidewire into the central circulation from the external jugular vein approach because the patient’s anatomy frequently directs the catheter into the subclavian rather than the innominate vein. It is also frequently difficult to pass the guidewire or catheter past the clavicle.

8 When is the femoral vein approach used?

The femoral vein is not a preferred approach because of the high risk of infection. Femoral venous cannulation may be undertaken when subclavian or internal jugular catheterization is unsuccessful. Femoral lines should be removed as soon as it is practical.

9 Review the different types of central venous catheters

Single-lumen catheters may have single distal port or multiport tips. Triple-lumen catheters have three channels and lumens at slightly different positions on the distal cannula, providing ports for simultaneous drug infusion, blood drawing, and CVP monitoring. They are available in 7.5- and 9-Fr sizes. A percutaneous introducer sheath is designed for insertion of a pulmonary artery catheter into the central circulation. It is a large-bore catheter (9 Fr) and has a side port that can be used for CVP monitoring or for fluid infusion. Some catheters are heparin coated.

10 How is a catheter introduced into the central venous circulation?

Before cannulation is attempted, Trendelenburg positioning will increase venous pressure at the target vessel. As the needle is advanced toward a vessel, slight and constant aspiration is required. Occasionally during needle advancement the vessel walls will collapse on themselves so the needle passes through the entire vessel and blood can be aspirated by slowly withdrawing the needle, all the while gently aspirating. Finally, thorough knowledge of adjacent vital structures is important to avoid unwarranted complications.

Although a catheter can be inserted through a large-bore needle, the most common technique involves passing it over a guidewire, commonly referred to as the Seldinger technique. An 18- or 20-G needle is introduced into the vessel, and a guidewire is threaded through the needle and into the vein. The needle is removed, leaving the guidewire in place. The catheter is then passed over the guidewire and into the vessel. Finally the guidewire is removed. The obvious benefit of the Seldinger technique rests in the use of a smaller-gauge introducer needle.

11 In attempting a central venous puncture, dark blood returns. Does this satisfy you that you are indeed within a vein?

Arterial blood may be dark because the patient is cyanotic, cardiac output is inadequate, or the patient may have methemoglobinemia, for example. The flow of blood also may be nonpulsatile in cardiac failure. The best way to determine whether you are indeed in a vein is to thread a short, small-gauge catheter (e.g., 18- or 20-G) over the wire, remove the wire, and transduce the small catheter.

12 How is central venous pressure measured?

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