Continuing Education Activity

A central line is a large-bore central venous catheter that is typically placed using a sterile technique unless a patient is unstable, in which case sterility may be a secondary concern. Some indications for central venous line placement include fluid resuscitation, blood transfusion, drug infusion, central venous pressure monitoring, pulmonary artery catheterization, emergency venous access for patients in which peripheral access cannot be obtained, and transvenous pacing wire placement. This activity describes the indications and technique involved in central line placement and highlights the role of the interprofessional team in ensuring that the procedure is performed safely.

Objectives:

• Describe the anatomy that is relevant to central line placement.
• Outline the complications associated with central line placement.
• Summarize the equipment required for central line placement.
• Explain a structured, interprofessional team approach to provide effective care to and appropriate surveillance of patients undergoing central line placement.

Introduction

A central venous line (CVL) is a large-bore central venous catheter that is placed using a sterile technique (unless an urgent clinical scenario prevents sterile technique placement) in certain clinical scenarios.[1][2][3][4]

Anatomy and Physiology

In emergency medical practice, there are three possible sites for CVL placement in the adult patient. Each has advantages and disadvantages. The placement sites include the internal jugular vein, femoral vein, and subclavian vein. The right internal jugular vein and left subclavian vein are the most direct paths to the right atrium via the superior vena cava. The femoral veins are compressible sites and as such may be more appropriate for coagulopathic patients. The subclavian vein approach is at higher risk for pneumothorax than the internal jugular vein approach. Ultrasound guidance can be very helpful in all approaches and is the recommended approach. However, when ultrasound guidance is not feasible for various reasons, such as the emergency nature of a procedure, lack of equipment, or a patient's anatomy in a situation where there is limited room for the ultrasound transducer in the subclavian approach while manipulating the needle, CVLs may be placed using anatomical landmarks without ultrasound.

Indications

There are many different indications for placing a CVL, but in emergency medicine, the most common indications include:

• Fluid resuscitation (including blood products)
• Drug infusions that could otherwise cause phlebitis or sclerosis (e.g., vasopressors and hyperosmolar solutions)
• Central venous pressure monitoring, pulmonary artery catheter introduction
• Emergency venous access (due to difficult peripheral intravenous access)
• Transvenous pacing wire placement

Contraindications

Contraindications include distorted local anatomy (such as for trauma), infection overlying the insertion site, or thrombus within the intended vein. Relative contraindications include coagulopathy, hemorrhage from target vessel, suspected proximal vascular injury, or combative patients.

Equipment

Most central line kits include:

• Syringe and needle for local anesthetic
• Small vial of 1% lidocaine
• Syringe and introducer needle
• Scalpel
• Guidewire
• Tissue dilator
• Sterile dressing
• Suture and needle
• Central line catheter (of which there are several types, including triple-lumen, dual-lumen, and large bore single-lumen)

In addition, the operator will require a sterile gown, cap, sterile gloves, sterile gauze, sterile saline, face mask, and a sterile cleansing solution such as chlorhexidine. The operator should ensure that ultrasound, sterile ultrasound gel, and a sterile ultrasound probe are part of the setup as well.

Preparation

Place the patient in the appropriate position for the site selected, then prepare the site in a sterile fashion using the sterile solution, sterile gauze, and sterile drapes. For the internal jugular and subclavian approach, place the patient in reverse Trendelenburg with the head turned to the opposite side of the site. For the femoral vein, place the patient in the supine position with the inguinal area exposed; this usually means the target leg should be bent at the knee with the lateral aspect resting on the stretcher or bed. It is recommended to place the patient on cardiopulmonary monitoring for the duration of the procedure.

Technique

The steps are as follows:

1. Infiltrate the skin with 1% lidocaine for local anesthesia around the site of the needle insertion.
2. Use the bedside ultrasound to identify the target vein.
3. If using landmarks for the subclavian vein CVL, the needle should be inserted approximately 1 cm inferior to the junction of the middle and medial third of the clavicle. If using landmarks for the femoral line CVL, the needle insertion site should be located approximately 1 cm to 3 cm below the inguinal ligament and 0.5 cm to 1 cm medial to where the femoral artery is pulsated.  
4. Insert the introducer needle with negative pressure until venous blood is aspirated. For the subclavian CVL, insert the needle at an angle as close to parallel to the skin as possible until contact is made with the clavicle, then advanced the needle under and along the inferior aspect of the clavicle. Next, direct the tip of the needle towards the suprasternal notch until venous blood is aspirated.  Whenever possible, the introducer needle should be advanced under ultrasound guidance to ensure the tip does not enter the incorrect vessel or puncture through the distal edge of the vein.
5. Once venous blood is aspirated, stop advancing the needle.  Carefully remove the syringe and thread the guidewire through the introducer needle hub.
6. While still holding the guidewire in place, remove the introducer needle hub.
7. If possible, use the ultrasound to confirm the guidewire is in the target vessel in two different views.
8. Next, use the scalpel tip to make a small stab in the skin against the wire just large enough to accommodate the dilator (and eventually, the central venous catheter). Insert the dilator with a twisting motion.
9. Advance the CVL over the guidewire. Make sure the distal lumen of the central line is uncapped to facilitate passage of the guidewire.
10. Once the CVL is in place, remove the guidewire. Next, flush and aspirate all ports with the sterile saline.
11. Secure the CVL in place with the suture and place a sterile dressing over the site.

Complications

Potential complications should be explained to the patient if possible while obtaining informed consent. Complications include pain at cannulation site, local hematoma, infection (both at the site as well as bacteremia), misplacement into another vessel (possibly causing arterial puncture or cannulation), vessel laceration or dissection, air embolism, thrombosis, and pneumothorax requiring a possible chest tube.[5][6][7]

Clinical Significance

Clinical pearls for consideration:

• A chest X-ray should be performed immediately for the internal jugular and subclavian lines to ensure proper placement and absence of an iatrogenic pneumothorax. 
• Be sure you are withdrawing venous blood before dilation and cannulation of the vessel.  
• If internal jugular CVL attempt is unsuccessful, move to the ipsilateral subclavian vein. Never attempt the opposite side without a chest X-ray or ultrasound first to avoid bilateral pneumothoraces. 
• Never let go of the guidewire as it may migrate distally into the vessel. Never force the wire on insertion because it may cause damage to the vessel or surrounding structures. Forcing the wire could also cause it to kink making removal difficult or impossible.
• Always place your finger over the open hub of the needle to prevent an air embolism.
• Always confirm placement with ultrasound, looking for reverberation artifact of the needle and/or tenting of the vessel wall. Needles cannot be visualized on ultrasound. Wires can be visualized so the operator can confirm at that step as well.
• A venous blood gas can be aspirated off a femoral line to ensure it is not arterial.

Enhancing Healthcare Team Outcomes

Central lines are inserted by many healthcare professionals. However, the monitoring of these lines is usually done by the nurses. The site of entry has to be kept clean and the nurse has to monitor it for signs of infection. Depending on which location the line was inserted, complications also have to be monitored like a pneumothorax, hematoma, bleeding or extravasation. In general, healthcare workers should avoid lines in the groin for more than 24 to 48 hours as they are prone to infections and also make it difficult for the patient to ambulate or get out of bed. To ensure good practice and limit complications, most hospitals now have an interprofessional team of healthcare professionals who are in charge of central line insertion and monitoring, each one checking and communicating any issues noted to the rest of the team so corrective action can take place if necessary. Such universal practice has been shown to limit infections. [8][9](Level V)