Central venous catheter: sites, Seldinger technique and checks

Procedure

A thin tube is placed through a large vein in the neck, chest or groin so its tip lies near the heart, for strong drugs and monitoring.

Updated Nov 13, 2026

What it is

A central venous catheter (CVC) is a catheter whose tip lies in a large central vein, ideally the lower superior vena cava near its junction with the right atrium. It is placed through the internal jugular, subclavian or femoral vein, almost always by the Seldinger technique: a needle enters the vein, a flexible guidewire is passed through it, the needle is removed, the track is dilated and the catheter is railroaded over the wire, which is then withdrawn. Each site has a trade-off. The internal jugular is easy to see with ultrasound and compressible, but sits close to the carotid artery and the lung apex. The subclavian has the lowest infection rate and is comfortable for the patient, but cannot be compressed and carries the highest risk of pneumothorax. The femoral is quick and away from the chest during resuscitation, but has more infection and thrombosis. Ultrasound guidance is the standard for the internal jugular and is increasingly used at every site. A line inserted with a full sterile bundle and checked properly (blood aspirated from every lumen, venous position confirmed, tip and lungs seen on a chest X-ray for neck and chest lines) is safe to use; most serious harm comes from skipping one of those checks.

Indications

Vasopressors and inotropes, which should run centrally once started for more than a short time.
Irritant or vesicant infusions: parenteral nutrition, some chemotherapy, hypertonic or concentrated solutions.
No usable peripheral access in a patient who needs intravenous treatment.
Haemodynamic monitoring: central venous pressure and central venous oxygen saturation.
Access for haemodialysis, plasmapheresis or a transvenous pacing wire (wider catheters or introducers).

Contraindications and precautions

Infection, burn or injury over the chosen site, or a known thrombosis of that vein: choose another site.
Coagulopathy or low platelets: not absolute, but prefer a compressible site (jugular or femoral) over the subclavian.
Severe lung disease or an existing pneumothorax: avoid the opposite subclavian; place it on the side of a chest drain if one is needed.
Distorted anatomy (neck surgery, radiotherapy, a cervical collar) makes the jugular harder; plan the site with ultrasound.
An uncooperative patient and no experienced help: stop and get a senior; sterile technique and ultrasound need time.

Equipment

Central line pack: catheter of the chosen lumen number, introducer needle, syringe, guidewire, scalpel and dilator.
Full sterile barrier: cap, mask, sterile gown and gloves and a large drape covering the patient.
Chlorhexidine in alcohol for the skin, and local anaesthetic with a fine needle.
Ultrasound machine with a linear probe, sterile probe cover and sterile gel.
Saline-filled syringes to flush every lumen, needle-free caps, suture or securing device and a clear dressing.

Step by step (and why)

Consent, checklist and a second person — the bundle of checks is what cuts infections and complications.
Scan the vein first: size, compressibility, clot and the artery beside it — it chooses the site and the angle.
Position: head down for jugular and subclavian, flat for femoral — the vein fills and air is less likely to enter.
Hand hygiene, full barrier precautions, skin prep allowed to dry, large drape — central lines need full asepsis.
Infiltrate local anaesthetic and puncture under ultrasound, aspirating — dark, non-pulsatile blood suggests the vein.
Pass the wire through the needle, watching the ECG; hold it at all times — ectopy means it is too deep: pull back.
Confirm the wire sits in the vein on ultrasound before dilating — dilating an artery causes serious bleeding.
Nick the skin, dilate only the track, then railroad the catheter and remove the wire — never dilate deeper than needed.
Aspirate and flush every lumen, secure and dress the line — free return of blood shows each lumen is in the vein.
Order a chest X-ray for neck and chest lines and document — tip position and a pneumothorax are checked before use.

Choosing the site

Site	Advantages	Drawbacks
Internal jugular	Easy to see with ultrasound, compressible, direct route to the vena cava	Carotid nearby, pneumothorax possible, awkward to dress in the neck
Subclavian	Lowest infection rate, comfortable, landmarks stable in shock	Not compressible, highest pneumothorax risk, harder under ultrasound
Femoral	Fast, away from the airway and chest compressions, no pneumothorax	More infection and thrombosis, limits mobility, tip not central for pressure readings

Complications

Arterial puncture or cannulation: carotid or subclavian injury, haematoma, stroke; never dilate before confirming the vein.
Pneumothorax or haemothorax, mainly with subclavian and low jugular approaches.
Air embolism: sudden breathlessness, hypotension; clamp the line, lie the patient on the left side head down, give oxygen.
Arrhythmias from the wire or tip in the heart; lost or knotted guidewire.
Late problems: catheter-related bloodstream infection, venous thrombosis, malposition and catheter occlusion.

Next step

Do not use the line for vasopressors or irritant drugs until venous position and, for neck and chest lines, the X-ray are checked.
If the tip is in the right atrium or in the wrong vein, report it and adjust or replace the line as the unit decides.
Call a senior after two failed passes at one site, any arterial puncture, or a new pneumothorax.
Review the need for the line every day and remove it as soon as it is no longer needed: dwell time drives infection.
Remove it with the patient flat or head down and exhaling, then cover the site with an occlusive dressing to prevent air entry.

Test yourself

Think of the answer, then tap the question to see it.

Why is the patient tilted head down for an internal jugular or subclavian line?

It fills and widens the vein, making it easier to puncture, and raises venous pressure above atmospheric so air is less likely to be sucked in.

What must be confirmed before the dilator is passed over the guidewire?

That the wire is in the vein and not an artery, usually by seeing it in the vein on ultrasound in two views, or by a non-pulsatile transduced pressure.

Where should the tip of a jugular or subclavian catheter lie on the chest X-ray?

In the lower superior vena cava near the cavoatrial junction, roughly at the level of the carina, and the film is also checked for a pneumothorax.

What is the immediate management of a suspected air embolism from a central line?

Clamp or occlude the line, lie the patient on the left side head down to trap air in the right heart, give high-flow oxygen and call for help.

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Educational content; it does not replace supervised hands-on training, your institution's protocols or a prescriber's order. A procedure is learnt with a teacher and done only once you are trained to do it.

Sources: Central Venous Catheter Insertion (StatPearls (NCBI Bookshelf), 2025); Central Line Management (StatPearls (NCBI Bookshelf), 2026).

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