Central Line (Central Venous Catheter) - Detailed Study

1. Definition

2. Anatomy

Key Anatomical Points

• Lies lateral to the internal carotid artery inside the carotid sheath
• Overlies the carotid artery in more than 50% of patients (varies significantly)
• Joins the subclavian vein to form the brachiocephalic vein
• The right IJV offers a shorter, straighter course to the SVC and avoids the thoracic duct (which enters on the left side)

• Crosses under the clavicle at the medial-to-proximal third of the clavicle
• The subclavian artery lies posterior and superior
• The thoracic duct joins the left subclavian vein at its junction with the left IJV
• Dome of the pleura lies posterior and inferior - risk of pneumothorax

• Travels in the femoral sheath deep to the medial third of the inguinal ligament
• Mnemonic for lateral-to-medial arrangement: NAVEL - Nerve, Artery, Vein, Empty space, Lymphatics
• Always cannulate below the inguinal ligament; injury above can cause retroperitoneal hemorrhage

3. Indications

4. Types of Central Lines

4a. Non-Tunnelled CVCs

• Standard triple-lumen or double-lumen catheters
• Inserted percutaneously at the bedside
• Short-term use (days to weeks)
• Single-, double-, or triple-lumen configurations available

4b. Tunnelled CVCs

• Hickman line: Most common; cuffed Silastic catheter, the Dacron cuff is placed halfway along the subcutaneous tunnel as a bacterial barrier; used for chemotherapy, prolonged TPN, bone marrow transplantation
• Groshong catheter: Has a pressure-sensitive valve at the tip (reduces backflow of blood into the catheter)
• Haemodialysis catheter: Large-bore, dual-lumen tunnelled line for dialysis access

4c. Implantable Ports (Port-a-Cath)

• Totally subcutaneous reservoir connected to a central catheter
• Accessed via needle through the skin
• Lowest infection rate among long-term devices
• Preferred for intermittent long-term chemotherapy

4d. Peripherally Inserted Central Catheter (PICC)

• Inserted via basilic, brachial, or cephalic vein in the arm
• Tip advanced to SVC
• Lower immediate procedural risks (no pneumothorax)
• Higher DVT rates in long-term use

5. Technique - Seldinger (Guidewire) Method

Pre-procedure Checklist (Table 31-7 - Tintinalli's)

• Time-out: correct patient, correct side/location
• Hand hygiene immediately prior
• Site sterilized and allowed to dry
• Head-to-toe sterile drape
• ALL staff in room wearing masks
• Door kept closed; traffic minimized

6. Site-Specific Techniques

Internal Jugular Vein

• Anterior approach: Identify carotid pulse medial to site; enter at midpoint of medial aspect of the sternal head of sternocleidomastoid (SCM) at 30-45 degrees, aim toward the ipsilateral nipple. Venous return typically at 3-5 cm depth.
• Central approach: Enter at the apex of the triangle formed by the two heads of the SCM.
• US guidance is strongly recommended: IJV overlies the carotid artery in >50% of patients.

Subclavian Vein

• Patient head-down, neutral position, small towel under the thoracic spine
• Landmark: junction of middle and medial thirds of the clavicle
• Direct needle toward the suprasternal notch at a 10-degree angle, parallel to chest surface
• "Walk" the needle down the clavicle if bone is hit
• Venous return at 3-5 cm

• Better US visualization of the proximal subclavian vein
• Longitudinal needle-US approach preferred to avoid pneumothorax

Femoral Vein

• Patient supine, reverse Trendelenburg, hip slightly abducted, leg externally rotated
• Femoral vein is just medial to the femoral artery, 1-2 cm below the inguinal ligament
• 45-degree angle of approach
• In pulseless arrest - "V" technique: thumb on pubic tubercle, index finger on anterior superior iliac spine; femoral vein at the interdigital space just below the inguinal ligament
• Always insert below the inguinal ligament

7. Ultrasound Guidance

• Improves first-attempt success rates and reduces complications, especially for less-experienced operators
• Recommended in both adult and pediatric patients
• Perform a preliminary scan before the procedure to assess vessel patency; for IJV/subclavian, document presence of sliding lung (to serve as a baseline if pneumothorax is later suspected)
• Short-axis (transverse/out-of-plane) view: Allows visualization of the vein and adjacent artery simultaneously; requires transducer fanning to track the needle tip
• Long-axis (longitudinal/in-plane) view: Needle must remain precisely in plane; allows full-length needle visualization; preferred for subclavian
• Neither approach is conclusively superior
• Always visualize the guidewire in short and long axis to confirm venous placement before dilation
• After the procedure, chest radiograph confirms catheter position; ultrasound can also be used with vascular and cardiac views

8. Tip Position

• Ideal position: SVC, just above the right atrium (at the SVC-RA junction)
• Must NOT be in the right atrium or right ventricle - risk of arrhythmia and perforation
• Confirmed by chest radiograph or fluoroscopy
• For tunnelled lines: image intensifier/fluoroscopy in the theatre is the standard

9. Complications

Immediate (Procedural)

Early

Late

10. Prevention of Complications

Infection Prevention (CLABSI Bundle)

• Strict maximal sterile barrier precautions
• Chlorhexidine skin antisepsis
• Avoid femoral site when possible
• Remove catheter as soon as no longer needed
• Catheter tunnelling (as in Hickman lines) reduces infection risk
• Biopatch (chlorhexidine disc) at insertion site provides local antisepsis for 7 days
• Dated sterile transparent dressing; change every 7 days or when soiled/loose
• Review of necessity daily

Pneumothorax Prevention

• Use US guidance, especially for subclavian lines
• Long-axis approach for the subclavian vein
• Do not attempt bilateral subclavian access without ruling out ipsilateral pneumothorax first

11. Securing and Dressing

• A rubber clamp is placed over the catheter a few centimeters from the insertion site
• Covered with a blue plastic fastener; both are sutured to skin
• The catheter hub is also sutured to skin
• Alternatively, skin staples may be used through anchoring eyes
• Biopatch (chlorhexidine hydrophilic disc) placed at skin entry site for 7 days of local antisepsis
• A clear Tegaderm dressing is applied over the entire site
• CXR is obtained to confirm tip position at the SVC level

12. Special Types and Long-Term Devices

Hickman Line (Tunnelled)

• Cuffed Silastic catheter tunnelled subcutaneously
• Dacron cuff placed halfway along the tunnel acts as a bacterial barrier; it becomes fixed by fibrosis
• Extravascular cuff placement: if placed at the mouth of the tunnel, it seals easily and is simpler to remove; if halfway, it requires more dissection at the end of treatment
• Inserted via cephalic, external jugular, or internal jugular vein
• Used for: prolonged chemotherapy, bone marrow transplantation, long-term TPN

Implantable Port

• Totally subcutaneous; accessed by needle puncture through skin
• Lowest infection rate
• Preferred for intermittent use

Haemodialysis Catheter

• Large-bore, dual-lumen tunnelled line
• Placed in the IJV or subclavian; tip in the SVC/right atrium

13. Paediatric Considerations (Harriet Lane Handbook)

• Choice of catheter size is based on primary disease, intended use, and the child's age, weight, and height
• Femoral access is often the site of choice in infants/small children when other sites are more difficult
• Paediatric indications include inability to obtain peripheral IV access, hemodynamic monitoring, administration of vasopressors, chemotherapy, and TPN (see Pediatric Table 114-3 in Tintinalli's)

14. Site Comparison Summary

Sources

• Tintinalli's Emergency Medicine: A Comprehensive Study Guide, Chapter 31 (Central Venous Access and Anatomy, US Technique)
• Roberts & Hedges' Clinical Procedures in Emergency Medicine, Chapter 22 (Central Venous Catheterization, Securing a CVC)
• Murray & Nadel's Textbook of Respiratory Medicine (Ultrasound-guided CVC Placement)
• Pye's Surgical Handicraft, 22nd Edition (Central Venous Access, Tunnelled Lines)
• The Harriet Lane Handbook, 23rd Edition (Paediatric CVC)
• Barash, Cullen & Stoelting's Clinical Anesthesia, 9e (Indications in perioperative monitoring)