[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anaesthesia and ICU](https://durgical.com/en/anaesthesia/) › [Critical care (ICU)](https://durgical.com/en/anaesthesia/areas/critical-care/) › Central lines in the ICU: choice, checks and removal

# Central lines in the ICU: choice, checks and removal

- Concept

A central line is a thin tube placed in a large vein near the heart to give strong drugs and fluids and to measure pressures; it helps but carries risks.

Updated Nov 13, 2026

## Key points

- Ideal tip position: the lower superior vena cava at the cavoatrial junction; check it (and look for pneumothorax) after jugular or subclavian placement before using the line.
- Real-time ultrasound guidance reduces failed attempts, arterial puncture and pneumothorax, especially at the internal jugular vein.
- Confirm venous placement of the wire before dilating: dilating an artery can cause major bleeding or stroke.
- The subclavian site has the lowest infection rate but risks pneumothorax and cannot be compressed; the femoral site is quick in emergencies but is avoided in adults when possible.
- Remove a line with the patient lying flat or head-down and during expiration or a breath-hold, to prevent air embolism.

On this page

- The basics Key points
- What it is
- Key points
- Components
- How it works
- Step by step
- Choosing the site
- In practice
- Next step
- Elsewhere in DurgiPedia

- Study Test yourself

- Connections Connections

## What it is

A central venous catheter is a line whose tip lies in a large central vein, ideally the lower superior vena cava near its junction with the right atrium. In the intensive care unit it is used to give vasopressors and other drugs that irritate small veins, to give parenteral nutrition, to sample blood often, to measure central venous pressure and central venous oxygen saturation, and, with a wide-bore double-lumen catheter, to run renal replacement therapy or plasma exchange. The common sites are the internal jugular, subclavian and femoral veins; peripherally inserted central catheters (PICCs) enter through an arm vein for longer use. Each site trades off ease, bleeding control, pneumothorax risk, infection and thrombosis. Real-time ultrasound guidance, full aseptic technique and confirming that the wire and catheter are in a vein before dilating have made insertion safer, but every line still carries the risks of infection, thrombosis and mechanical injury, so its need is reviewed every day and it is removed as soon as it is no longer essential.

## Key points

- Indications: vasopressors or vesicant drugs, parenteral nutrition, poor peripheral access, haemodynamic monitoring, and dialysis or plasma exchange catheters.
- Relative contraindications: infection or burn at the site, thrombosis of the target vein, and uncorrected severe coagulopathy (favour a compressible site if needed).
- Internal jugular: the usual first choice with ultrasound, compressible, with a direct path to the right atrium on the right side.
- Subclavian: lowest infection and thrombosis rates and more comfortable for an awake patient, but higher pneumothorax risk and not compressible.
- Femoral: fast, away from the airway and chest during resuscitation, but higher infection and thrombosis risk and hampers mobilisation.
- PICCs suit longer courses on the ward, but have higher thrombosis rates and are avoided in chronic kidney disease to preserve arm veins for fistulas.

## Components

- Catheter: one to five lumens; more lumens mean more access points and a higher infection risk, so the fewest needed are used.
- Guidewire (Seldinger technique), needle, dilator and a sterile ultrasound probe cover.
- Transducer set for central venous pressure and a port for central venous oxygen saturation samples.
- Sterile, transparent dressing, often chlorhexidine-impregnated, and needleless connectors that are scrubbed before each access.

## How it works

- The tip sits in a large vein with high flow, which dilutes irritant drugs at once and protects the vessel wall.
- A tip too deep in the right atrium can cause arrhythmia or, rarely, perforation and tamponade; a tip in a small vein causes thrombosis and extravasation.
- Air can be sucked into an open central vein when intrathoracic pressure is negative (inspiration, sitting up), which is why lines are opened and removed flat or head-down.
- The catheter surface is colonised within days by skin organisms that form a biofilm, so infection risk grows with time and handling.

## Step by step

- Confirm the indication and choose the site and catheter — the fewest lumens and the safest site lower the risk of infection and injury.
- Scan the vein with ultrasound before preparing — thrombosis, small size or a nearby artery change the plan.
- Use full aseptic technique with maximal sterile barriers — most early infections start at insertion.
- Insert under real-time ultrasound and confirm the wire in the vein before dilating — this prevents arterial dilation.
- Never let go of the guidewire, and count it out at the end — a lost wire is a serious, preventable error.
- Confirm tip position and exclude pneumothorax before use — a malpositioned line can harm when vasopressors run through it.
- Review the need for the line every day — each extra day adds risk of infection and thrombosis.
- Remove it flat or head-down during expiration, then press and seal — this prevents bleeding and air embolism.

## Choosing the site

| Site | Advantages | Drawbacks |
| --- | --- | --- |
| Internal jugular | Ultrasound-friendly, compressible, low pneumothorax risk with ultrasound | Uncomfortable for awake patients; carotid artery close by |
| Subclavian | Lowest infection and thrombosis rates; comfortable | Pneumothorax; vessel cannot be compressed if it bleeds |
| Femoral | Quick, away from airway and chest compressions | Higher infection and thrombosis risk; limits mobilisation |
| PICC (arm) | Long courses, easy insertion outside the ICU | Higher thrombosis rate; avoid in chronic kidney disease |

## In practice

- Dark, non-pulsatile return is not proof of venous placement in a hypoxic or hypotensive patient; use ultrasound, manometry or a blood gas.
- If a dilator or catheter has entered an artery, leave it in place and call vascular or interventional help; do not pull it out.
- New hypoxaemia or falling blood pressure after a jugular or subclavian attempt: think of pneumothorax or haemothorax.
- Arrhythmia during insertion usually means the guidewire is in the heart: withdraw it a little.
- A swollen arm or neck on the line side suggests catheter-related thrombosis: confirm with ultrasound.

## Next step

- Before using a new jugular or subclavian line, confirm the tip position and the absence of pneumothorax and record it in the notes.
- Call a senior at once for suspected arterial cannulation with a dilator, a lost guidewire, or a new pneumothorax.
- Ask every day whether the line is still needed, and remove it as soon as peripheral access is enough.
- After removal, keep the patient lying down for a while with an occlusive dressing, and watch for bleeding and breathlessness.
- Suspected air embolism (sudden breathlessness, hypotension, a mill-wheel murmur): give oxygen, lay the patient head-down on the left side and call for help.

## Test yourself

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

## Where should the tip of a central venous catheter ideally lie?

In the lower superior vena cava, close to its junction with the right atrium.

## Why must venous placement be confirmed before dilating during central line insertion?

Dilating an artery by mistake can cause major bleeding, a haematoma compressing the airway, or stroke; ultrasound, manometry or a blood gas confirm the vein first.

## Which central venous site has the lowest infection rate, and what is its main drawback?

The subclavian vein; it carries a higher risk of pneumothorax and cannot be compressed if it bleeds.

## How is air embolism prevented when a central line is removed?

The patient lies flat or head-down and the catheter comes out during expiration or a breath-hold, followed by pressure and an occlusive dressing.

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## Elsewhere in DurgiPedia

- [Central venous catheter: sites, Seldinger technique and checks](https://durgical.com/en/clinical-skills/central-venous-catheter-sites-seldinger-technique-and-checks/)
- [Central venous catheter care](https://durgical.com/en/nursing/central-venous-catheter-care/)
- [Clean and sterile technique: medical and surgical asepsis](https://durgical.com/en/nursing/clean-and-sterile-technique-medical-and-surgical-asepsis/)

## Connections

## Related 6

- [Catheter-related bloodstream infection: prevention and response](https://durgical.com/en/anaesthesia/catheter-related-bloodstream-infection-prevention-and-response/)
- [Haemodynamic monitoring: arterial line, CVP, cardiac output and lactate](https://durgical.com/en/anaesthesia/haemodynamic-monitoring-arterial-line-cvp-cardiac-output-and-lactate/)
- [The ICU daily bundle (FAST HUGS and similar checklists)](https://durgical.com/en/anaesthesia/the-icu-daily-bundle/)
- [Vasopressors and inotropes by receptor and mechanism](https://durgical.com/en/anaesthesia/vasopressors-and-inotropes-by-receptor-and-mechanism/)
- [Nutrition in the ICU: enteral first](https://durgical.com/en/anaesthesia/nutrition-in-the-icu-enteral-first/)
- [Renal replacement therapy in the ICU: when and which](https://durgical.com/en/anaesthesia/renal-replacement-therapy-in-the-icu-when-and-which/)

## Related conditions 2

- [Pneumothorax](https://durgical.com/en/conditions/pneumothorax/)
- [Deep vein thrombosis](https://durgical.com/en/conditions/deep-vein-thrombosis/)

## In Pharmacology 2

- [Chlorhexidine](https://durgical.com/en/pharmacology/chlorhexidine/)
- [Heparin](https://durgical.com/en/pharmacology/heparin/)

[← All of anaesthesia](https://durgical.com/en/anaesthesia/)

Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: [Central Venous Catheter Insertion](https://www.ncbi.nlm.nih.gov/books/NBK557798/) (StatPearls (NCBI Bookshelf), 2025); [Central Line Management](https://www.ncbi.nlm.nih.gov/books/NBK539811/) (StatPearls (NCBI Bookshelf), 2026).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anaesthesia/central-lines-in-the-icu-choice-checks-and-removal/