What is a central line and how is it placed?

What is a Central Line and How to Place It

Definition and Purpose

A central line (central venous catheter) is a catheter inserted into a large vein with its tip positioned at the junction of the superior vena cava and right atrium, used for administering medications, fluids, parenteral nutrition, hemodialysis, hemodynamic monitoring, and blood sampling. 1, 2

Central venous access devices are essential for patients requiring:

• Long-term intravenous therapy (>30 days) including chemotherapy, antibiotics, and parenteral nutrition 1
• Rapid fluid resuscitation and vasoactive medication administration 2
• Central venous pressure monitoring and venous oxygen saturation measurement 3, 2
• Hemodialysis access 1
• Frequent blood sampling 1

Types of Central Venous Catheters

Short-term (1-3 weeks)

• Non-tunneled catheters: 20-30 cm long, single or multiple lumens, 5F-14F, for continuous short-term infusions and monitoring 1

Intermediate-term (<3 months)

• PICCs: Inserted through peripheral arm veins (basilica, brachial, or cephalic) into the superior vena cava, 2F-7F with 1-3 lumens 1
• Hohn catheters: Non-tunneled, centrally inserted, 20 cm long silicone catheters 1

Long-term (>3 months)

• Tunneled catheters: Hickman, Broviac, Groshong lines for chemotherapy, antibiotics, parenteral feeding 1, 2
• Totally implantable ports: Subcutaneous reservoir with catheter, lowest infection risk, accessed through intact skin 1, 2

Site Selection

Preferred Sites (in order of preference)

The right internal jugular vein is the preferred first-choice site due to its straighter path to the superior vena cava, shorter catheter length required, and fewer mechanical complications. 2

1. Internal jugular vein (especially right-sided): Preferred for most indications, lower thrombotic complications with right-sided approach 1, 2
2. Subclavian vein: Lowest infection risk among all sites, but avoid in patients with advanced kidney disease or on hemodialysis due to risk of central venous stenosis 4, 2
3. Femoral vein: Should be avoided unless contraindications exist to other sites (e.g., SVC syndrome) due to increased infection and thrombosis risk 1, 4

Site-Specific Contraindications

• Femoral: Higher infection and thrombosis rates, relatively contraindicated for parenteral nutrition 4, 2
• Subclavian: Avoid in hemodialysis patients (causes stenosis preventing future AV fistula), severe respiratory compromise 4
• Left-sided access: Associated with poor blood flow, higher stenosis and thrombosis rates 2

Placement Technique

Pre-Procedure Preparation

Careful preoperative assessment including medical history, physical examination, and appropriate laboratory/radiological tests is essential. 1

Insertion should be performed under strict sterile conditions using maximal sterile barrier precautions. 1, 4

• Use chlorhexidine solutions with alcohol for skin preparation 1
• Perform under local anesthesia with or without sedation 1
• Antimicrobial prophylaxis is NOT recommended for catheter colonization prevention 1

Insertion Approaches

Percutaneous Seldinger Technique (Primary Method)

Real-time ultrasound guidance is strongly recommended for all internal jugular vein catheterizations to improve success rates and reduce complications. 1, 2, 5

Step-by-step procedure:

1. Ultrasound identification: Use 2D ultrasound for vessel localization—randomized trials show higher first-attempt success for internal jugular vein compared to landmark approach 1

2. Needle insertion: Pass needle toward chosen vessel under ultrasound guidance; consider using a finder (seeker) needle first 1

3. Guidewire placement: Once needle is in vein, introduce guidewire through needle into vessel, then remove needle 6

4. Vessel dilation: Make small skin incision at guidewire base, advance dilator over guidewire, then remove 6

5. Catheter insertion: Railroad central venous catheter over guidewire into vein, then withdraw guidewire 6

Open Technique (Alternative)

The open technique (cephalic vein cut-down) is the best approach to avoid immediate complications, though less commonly used. 1

Catheter Tip Positioning

The catheter tip must be positioned at the junction between the right atrium and superior vena cava for accurate CVP measurement and optimal function. 1, 3, 2

Verification methods:

• Intraoperative fluoroscopy (preferred) 1
• Post-operative chest X-ray (standard) 1
• Intracavitary ECG method (alternative): Documents arrhythmia during wire insertion 1

Post-Procedure Care

Patients require 4-hourly observations including temperature, pulse, blood pressure, and respiratory rate. 1

• Chest X-ray required if patient develops dyspnea or chest wall pain 1
• Routine flushing with saline after completion of any infusion or blood sampling 1
• Implantable devices only require care until incision heals 1

Common Complications and Pitfalls

Mechanical Complications

• Pneumothorax: Higher risk with subclavian approach, especially in severe respiratory distress 4, 7
• Arterial puncture: Reduced significantly with ultrasound guidance 4
• Incorrect tip positioning: Leads to inaccurate CVP readings and malfunction 3, 4

Infectious Complications

• Catheter-related bloodstream infections: Highest risk with femoral site, lowest with subclavian 4, 2
• Multi-lumen catheters increase infection risk for home parenteral nutrition 2

Thrombotic Complications

• Venous thrombosis: Higher with PICCs (limiting long-term use), left-sided access, and femoral site 1, 2
• Subclavian stenosis: Precludes future AV fistula creation in dialysis patients 4, 2

Critical Pitfalls to Avoid

• Failing to use ultrasound guidance when available—significantly reduces mechanical complications 1, 4
• Ignoring site-specific risks—each approach has unique complications requiring consideration 4
• Over-interpretation of CVP values without considering clinical context, mechanical ventilation effects, or tricuspid regurgitation 3
• Placing subclavian lines in hemodialysis patients—causes irreversible central venous stenosis 4, 2
• Limiting catheter diameter selection—should be one-third or less of vein diameter 2