MRCS Part B Revision · Procedural and technical skills
Central Line — MRCS Part B Procedural and technical skills
By Dr Richard Miller, MBChB FRCS · Reviewed
Central Line is a procedural station. Two of the seventeen examined stations in the MRCS Part B OSCE are procedural. The procedural stations ask you to perform a practical task, usually on a model, while explaining what you are doing and why.
What you need to know for the Central Line station
Central Line Insertion
Introduction
- Wash your hands
- Introduce yourself
- Explain to the patient what you are about to do.
Preparation
- Tilt the head end of the bed down by 10°–15°.
- Draw up 10 ml of lidocaine; raise a bleb on the skin with a blue 27-gauge needle.
- Infiltrate local anaesthetic all around the site, working down toward the vein. Pull back on the plunger before injecting each time to ensure that you don't inject into the vein.
- Open the central line pack and take all of the items out. Ensure that the wire moves freely on its reel – you will need to advance the wire one-handed.
- Flush each port of the central line with saline or heparin saline, and close off each line except the distal (usually brown) line; the wire threads through this line.
- Attach a syringe to the large needle provided
Procedure
- Palpate the carotid artery with your left hand, covering the artery with your fingers. Insert the needle 0.5–1 cm laterally to the artery, aiming at a 45°angle to the vertical. In men, aim for the right nipple; in women, aim for the iliac crest. Advance slowly, aspirating all the time, until you enter the vein. If you fail to aspirate blood after entering 3–4 cm, withdraw, re-enter at the same point, but aim slightly more medially
- Alternatively, if you have been trained, a portable US machine can be used to locate the compressible IJV
- When the needle is in the vein, ensure that you can reliably aspirate blood. Remove the syringe, keeping the needle very still, and immediately put your thumb over the end of the needle.
- Insert the wire into the end of the needle, and advance the wire until at least 30 cm are inserted.
- Keeping one hand on the wire at all times, remove the needle, keeping the wire in place. Make a nick in the skin where the wire enters the skin. Insert the dilator over the wire and push into the skin as far as it will go. Remove the dilator.
- Insert the central line over the wire. Keep one hand on the wire at all times. When the central line is 2 cm away from the skin, slowly withdraw the wire back through the central line until the wire tip appears from the line port. Hold the wire here while you insert the line. Leave a few centimetres of the line outside the skin. Withdraw the wire and immediately clip off the remaining port.
- Attach the line to the skin with sutures. Tie loosely so as not to pinch the skin; this causes necrosis and detachment of the line. Clean the skin around the line once more, dry, and cover with occlusive dressings.
- Ensure that you can aspirate blood from each lumen of the line, then flush each lumen with saline or heparin saline.
Close
- Dispose of sharps
- Thank the patient
- Request follow up CXR
Central Line Summary
Central Lines are used to administer medication, fluids, to obtain blood tests and measure central venous pressure.
Images from this station
What are you asked at the Central Line station?
The station runs to 12 questions over nine minutes. These are the questions as they are put to you; the model answers are in the question bank.
- Surgical Skills: Central Line Insertion
- What kit will you require?
- Into which veins are central lines usually placed?
- Describe how you would identify the JVP
- Describe how you would insert a central line into the internal jugular vein What would you do first?
- How would you prepare your kit before inserting the line?
- Describe how you would insert the central line
- What would you do after inserting the central line?
- Other than the internal jugular vein where else are central lines commonly inserted?
- What are the benefits of using the right internal jugular vein?
- Why should you request a chest radiograph after inserting a central line?
- What are some other potential complications of central line insertion?
How is the procedural and technical skills station marked in MRCS Part B?
The two procedural stations are marked differently from each other. Procedural skills with a patient carries 8 marks for clinical and technical skill and 4 each for knowledge, communication and professionalism. Procedural skills, technical, performed on a model rather than a person, carries 12 for skill and 8 for knowledge, with no communication or professionalism marks available.
FAQ
What does the Central Line station ask?
It opens with "Surgical Skills: Central Line Insertion" and runs to 12 questions over nine minutes. The two procedural stations are marked differently from each other. Procedural skills with a patient carries 8 marks for clinical and technical skill and 4 each for knowledge, communication and professionalism. Procedural skills, technical, performed on a model rather than a person, carries 12 for skill and 8 for knowledge, with no communication or professionalism marks available.
What procedural skills are tested in MRCS Part B?
Two of the seventeen examined stations are procedural: one with a patient and one purely technical. Candidates most often report suturing, abscess incision and drainage, catheterisation and chest drain insertion.
How is a procedural station marked?
The station with a patient carries 8 of its 20 marks for clinical and technical skill and 4 each for knowledge, communication and professionalism. The technical station carries 12 for skill and 8 for knowledge, with no communication marks.
Should I talk while I perform the procedure?
At the station with a patient, yes: a third of the marks there are for communication and professionalism, and they are gone if you work in silence. At the purely technical station those marks do not exist, so the technique itself is what counts.
How many stations are in the MRCS Part B OSCE?
Seventeen examined stations of nine minutes each, with a minute to read the task before each one. Two preparation stations and at least one rest station bring the circuit to about twenty, and the exam takes about three and a half hours.
What is the pass mark for MRCS Part B?
There is no published pass mark. The cut score is set separately for Applied Knowledge and Applied Skills, for each circuit, by borderline regression. Published pass rates across the 2024/25 diets ranged from 51% to 66%.
Can I fail a station and still pass?
Yes. There is no rule about how many stations you may fail: the cut score applies to your total mark in each component, so a weak station costs the marks you lost on it and strong stations elsewhere can make them back. Applied Knowledge and Applied Skills are passed separately and must both be passed at the same sitting, so a strong anatomy performance cannot rescue a weak communication one.
Dr Richard Miller, MBChB FRCS
Station summaries are reviewed against the current intercollegiate MRCS syllabus and the published marking blueprint. Guidance changes between diets: check the royal colleges' own pages before relying on a date, a fee or a threshold.
Practise this station
The question bank carries the model answer to every question above, with the rest of the procedural and technical skills stations.
More procedural and technical skills stations