Choosing a central venous access site

Short answer

The internal jugular offers ultrasound visibility and compressibility; subclavian access offers an infection advantage but carries pleural and bleeding risks; femoral access avoids the pleura but raises concerns about thrombosis and ongoing groin-site care. These trade-offs should guide the choice alongside the patient’s anatomy.^[1][2][3]

What changes the decision?

Start with the treatment and the patient, then compare the available sites:

• Purpose and duration. Decide whether a temporary CVC is the right device. Dialysis, prolonged treatment and rapid infusion have different device requirements; the insertion site alone does not determine achievable flow. Select the smallest suitable catheter with the fewest necessary lumens.^[1]
• Anatomy and access history. Assess candidate veins with ultrasound immediately before insertion. Look for thrombosis, vessel size, depth and the relationship to arteries and other structures. Account for previous lines, surgery, radiotherapy, implanted devices and overlying infection.^[1][2]
• Consequences of a complication. Bleeding is harder to control at a non-compressible site. Pleural injury matters especially when respiratory reserve is poor. These risks may outweigh an infection advantage.^[2]
• Care after insertion. Consider whether the patient can tolerate the position, whether a dressing can remain secure and clean, and how the line will affect comfort and mobility. Match the approach to the operator’s competence and seek experienced help for difficult access.^[1]

Comparing the sites

The comparison applies to adult short-term access.^[1][2][3]

Internal jugular

The internal jugular vein is accessible to ultrasound, allowing the operator to assess its size, patency and relationship to the carotid artery. Compressibility is useful when bleeding risk is a concern, although a neck haematoma can still threaten the airway. Ultrasound-guided access and a compressible site reduce some risks; they do not remove the need for an individual bleeding assessment.^[1][2][4]

Neck anatomy, body habitus, facial hair, tracheostomy dressings and other equipment can affect access or dressing security. Ease of insertion is patient- and operator-dependent. For the practical sequence, see the ultrasound-guided internal jugular CVC guide.

Subclavian

For adult non-tunnelled CVCs, CDC guidance favours subclavian placement to reduce infection risk, provided mechanical risks and other contraindications are considered. The benefit must be weighed against pneumothorax, haemothorax and bleeding that cannot readily be compressed beneath the clavicle.^[2]

Femoral

Femoral access avoids the pleura and can leave the airway and chest available during resuscitation when central access is needed. Compression is possible at an appropriate groin puncture site, but haemorrhage can still be concealed in the retroperitoneum.^[4] During CPR, transmitted pulsation can also affect veins: pulsatility alone cannot reliably distinguish artery from vein. Use real-time ultrasound and confirm venous access.^[1]

Femoral catheters have a higher thrombosis risk in the 2025 guidance. CDC infection-prevention guidance advises avoiding femoral CVCs in adults where possible, but this does not establish a universal infection ranking for every patient. Groin contamination, dressing integrity, body habitus and mobility influence suitability. Reassess the ongoing need and site once the immediate clinical problem is controlled.^[1][2]

Does the side matter?

The right internal jugular generally offers a shorter, more direct route to the superior vena cava. Choose the side using ultrasound findings, access history and existing devices. Left-sided access requires attention to catheter length, course and tip position, and carries a rare risk of thoracic duct injury.^[1][5]

For a routine short-term femoral CVC, choose the side using the ultrasound assessment, local skin condition and existing or planned access. Do not assume that both sides are equally suitable in an individual patient.

Match the catheter to the vein

A large catheter in a small vein leaves less space for blood flow and increases concern about thrombosis. Choose the smallest device that meets the clinical need in a suitably sized vein. The 2025 Association of Anaesthetists guidance recommends that the catheter should ideally occupy no more than one-third of the vein’s cross-sectional area. This is an area ratio, not a diameter ratio.^[1]

This principle supports vessel preservation; it is not a guarantee against thrombosis. Device calibre, insertion trauma, tip position and patient factors also contribute.^[1]

What does the comparative evidence show?

The 3SITES randomised trial studied non-tunnelled CVCs in adults in intensive care. Subclavian placement reduced the combined outcome of catheter-related bloodstream infection or symptomatic deep-vein thrombosis compared with jugular or femoral placement. Femoral and jugular groups did not differ significantly for that combined outcome.^[3]

In the comparison where all three sites were suitable, pneumothorax requiring a chest drain occurred after 1.5% of subclavian insertions and 0.5% of jugular insertions. These are trial-specific rates for pneumothorax requiring drainage, rather than universal rates for all pneumothoraces. Ultrasound use differed between groups, limiting direct application to contemporary ultrasound-guided practice.^[3]

References