Central Line

Article Author:
Bryan England
Article Editor:
John Kiel
Updated:
11/10/2018 1:49:27 PM
PubMed Link:
Central Line

Introduction

Central venous catheterization is a skill frequently needed in the acute care setting. Patients who have multiple, noncompatible intravenous (IV) medications with limited peripheral access, or who are being given vasoactive or phlebosclerotic agents may not be suitably cared for with a peripheral IV alone. Some central lines are also placed for temporary or permanent hemodialysis access; these dialysis catheters are significantly larger than traditional double, triple, or quadruple lumen catheters placed in the emergency department (ED) or intensive care unit (ICU) setting. Central lines may also be placed to introduce Swan Ganz catheters to measure internal hemodynamics of the heart, or to introduce temporary transvenous pacemaker leads in the critically ill patient who has severe bradycardia or high-degree heart block: these are called introducer catheters. Most central lines are placed today via the Seldinger technique (a safety enhancement over the previous "cut-down" technique), in which the chosen vein is cannulated with a needle, a guide wire is inserted to maintain a tract through the skin into the vein, and the catheter is then inserted over the wire into the vein before the wire is removed. Nonetheless, this is still a procedure with ample opportunities for complications. This article focuses on the complications of line placement. [1],[2],[3]

Anatomy

Central venous catheters are placed typically in one of 3 large central veins: the internal jugular vein (IJ), subclavian vein (SCL), or femoral vein. These large diameter central veins are located universally near a large artery. In the lateral neck, the IJ is located next to the carotid artery, with the vein lying lateral to the artery in most patients, deep to the sternocleidomastoid muscle. The subclavian vein lies next to the subclavian artery, and courses out of the axilla across the lateral upper chest where it quickly dives deep to the clavicle before joining the internal jugular vein bilaterally, then joining together to form a common superior vena cava. The femoral vein lies in the femoral triangle of each thigh and maintains a medial relationship to the common femoral artery.[4] Proximity to adjacent vital structures (arteries and lungs principally) is perhaps of greatest concern when striving to perform this procedure without causing harm to the patient.[5],[6]

Indications

Central lines are placed for the following indications:

  • Hemodynamic instability that requires vasopressor support
  • Need to instill hyperosmolar agents or agents known to cause vein scarring (phlebosclerosis)
  • Inadequate peripheral IV access (either failure to obtain peripheral access anywhere, or needing multiple IVs to sustain and resuscitate a patient)

Contraindications

Contraindications to central line placement may vary based on the site chosen to cannulate. Common contraindications to central line placement are:

  • Coagulopathy (anticoagulated status, DIC, or other inherited or acquired coagulopathy): Placement at noncompressible sites are relatively contraindicated, due to the risk of hemorrhage
  • Infection at the insertion site (cellulitis, abscess)

Equipment

  • Central line insertion kit, which is usually manufacturer specific and most will at least contain the central line, guide wire, syringe, an introducer needle, a scalpel, a silk suture (on a Keith or curved needle) and a skin dilator
  • Sterile gloves and gown
  • Hat and mask
  • Drape or sterile towels to create a sterile barrier (to protect equipment and materials from becoming contaminated)
  • Antiseptic agent for skin preparation
  • Proper caps for each lumen port
  • Dressing to cover the insertion site
  • Local anesthetic (1% to 2% lidocaine is supplied in most commercial kits) with a syringe and needle to instill the medication

It is also helpful to ask if any specific additional items are needed per your institutional protocols (such as antibiotic sponges). If an ultrasound-guided technique is used, a sterile probe cover should also be available.[7],[8]

Personnel

When possible, having an assistant present during the procedure is helpful. However, the well-prepared and well-practiced clinician can place a central venous catheter with little to no assistance.

Preparation

Before any medical procedure, it is appropriate to take a moment to confirm that you are with the right patient, performing the right procedure at the right site (commonly called a "time out").[9]

Once the site is chosen, a topical antiseptic such as chlorhexidine or betadine is applied circularly to the skin in ever-enlarging circles. Once applied, the antiseptic should be allowed to dry to maximize the decrease in skin surface bacterial cell count.

It is also common practice to flush the central line with sterile saline

Technique

After donning sterile gown and gloves, and a hat and mask, and after the selected vein is prepped and draped, anesthetize the insertion site by injecting local anesthetic sufficient to create a wheal under the skin.  Continue to aim this needle towards the venous target, aspirating then injecting anesthetic into the subcutaneous tissue. Once the area is anesthetized, place the introducer needle into the skin, and advance toward the vein being cannulated, all the while aspirating with steady pressure. Once blood return is seen in the syringe attached to the introducer needle, the syringe can be removed. A guidewire is inserted through the needle into the vein, to a depth of at least 15 centimeters. Some commercial kits include a syringe with a wire-port located on the base of the plunger; another option is to insert the wire through this port into the vein. Make sure to insert enough wire to pass through the needle and syringe, as well as at least 10 centimeters into the cannulated vein. Next, remove the needle (and syringe if still attached), careful to leave the wire inserted in the skin and vein. Use the scalpel to make a small stab incision (approximately 2 mm) into the path of the guidewire, then slide the skin dilator over the wire into the subcutaneous tissue, to dilate the soft tissue all the way to and into the vein. Remove the dilator, then carefully insert the central line over the wire. Before allowing the distal tip to enter the skin, manually back the guidewire through the central line until the wire emerges from the central line port. Secure the proximal end of the wire and continue to guide the central line into the skin, subcutaneous tissue, and vein, over the wire. Remove the wire, apply appropriate caps to the central line ports (or clamp the line so that no blood can escape, and no air can enter the patient). Secure the central line to the skin with suture or staple per institutional guidelines, and apply a sterile dressing to cover the insertion site.[10]

Complications

  • Pneumothorax
  • Pericardial effusion/tamponade
  • Bleeding
  • Infection
  • Thrombosis
  • Injury to the nerves
  • Losing guidewire inside the vein
  • Air embolism
  • Arrhythmias [11]

Clinical Significance

With a central line, the patient cannot only be resuscitated, but the hydration status can be monitored by measuring the right atrial pressure.[12] One can also administer medications and total parenteral nutrition (TPN) via a central line.