Procedure stations are the bit of the MRCEM OSCE most candidates either over-rehearse or wing entirely. Both fail you. The examiner has a tick-list in front of them, and that tick-list is the same one a registrar in a UK ED would mentally run before opening a pack — gather kit, consent, asepsis, do the procedure cleanly, close the loop with imaging and documentation. If you verbalise that structure on every station, you can pass even on a procedure you’ve never actually done on a real patient.
This is the equipment-and-sequence checklist for the six procedures you are most likely to see, with the common pitfalls each examiner is watching for.
flowchart LR
A[Introduce
Confirm patient and procedure] --> B[Consent
Indication, risks, alternatives]
B --> C[Equipment
Check, lay out, ANTT]
C --> D[Procedure
Stepwise, verbalise]
D --> E[Debrief
Document, safety net]
TL;DR
The six SLO 6 procedure stations that come up most often in the MRCEM OSCE are:
- Lumbar puncture
- Seldinger chest drain (or open chest drain in trauma)
- Arterial blood gas / arterial line
- Knee joint aspiration
- Fascia iliaca block (landmark or ultrasound)
- Synchronised DC cardioversion / defibrillation
Shared principles every examiner is ticking off, regardless of procedure:
- Introduce yourself, confirm patient ID, allergies, analgesia, position, privacy.
- Indications, contraindications, complications — out loud, in patient-friendly language, then take written consent for invasive procedures.
- Hand wash, PPE, sterile field, ANTT — verbalised even if you can’t actually scrub at the bench.
- Confirm site (imaging review, ultrasound where indicated, anatomical landmarks).
- WHO/NatSSIPs pause: right patient, right side, right procedure, kit checked, assistant briefed.
- Local anaesthetic: name, concentration, max dose calculated, aspirate before inject.
- Post-procedure: confirmation imaging or test, safety-net to patient and nursing staff, documentation including GMC number, indication, technique, complications, samples sent.
If you run out of time, the post-procedure plan is usually where candidates lose the easy marks — say it first if you have to.
For more on this, see our guide to OSCE system examination station structure.
What is the generic structure for every procedure station?
SLO 6 (“Deliver key procedural skills”) is not really a test of whether you can stab a needle into a model. It’s a test of whether you can run a safe, structured, communicated procedure in 7 minutes. The technical procedure is usually only 30–40% of the marks; the wrapper is the rest.
Use the same opening 90 seconds on every station. It buys thinking time and earns the easy marks before you touch the kit:
- Wash hands, PPE, introduce — name, role, confirm patient name and DOB.
- Check pain, allergies, anticoagulants.
- Confirm indication and review imaging aloud.
- Explain procedure in plain English, name main risks, confirm understanding.
- Written consent for invasive procedures.
- Gather and check equipment on a clean trolley, verbalise the kit list.
- Pause — right patient, right side, right procedure, assistant briefed, monitoring on.
- Do the procedure — narrate each step, warn before painful bits, maintain asepsis.
- Close the loop — confirmation imaging/test, samples to lab, analgesia, safety-net, documentation including GMC number and indication.
If the examiner calls time, deliver step 9 anyway — that is where candidates most often leak marks.
Lumbar puncture: equipment, sequence and pitfalls
| Stage | What to say or do |
|---|---|
| Equipment | Sterile LP pack; atraumatic (pencil-point) spinal needle 22G with introducer; 5–10 mL syringe and 23G/25G needle for LA; 1% lidocaine; chlorhexidine 0.5% in 70% alcohol; sterile drape, gloves, gown; manometer with 3-way tap; 3–4 numbered sterile sample bottles; fluoride-oxalate tube for CSF glucose; sharps bin; dressing. |
| Pre-procedure | Indications (suspected meningitis, SAH after negative CT, IIH, intrathecal drugs). Contraindications (raised ICP, focal neurology, GCS drop, coagulopathy, platelets <50, INR >1.5, anticoagulants, local skin infection, suspected cord compression). Send paired blood glucose. Written consent. |
| Positioning | Left lateral decubitus, knees to chest, back at edge of bed, spine parallel to floor — this is what’s needed for accurate opening pressure. Sitting position is acceptable for sample only. |
| Landmarks | Tuffier’s line (between the iliac crests) ≈ L4. Insert at L3/L4 or L4/L5. |
| Sequence | Asepsis, drape, LA dermal bleb then infiltrate intercostal space, allow time. Insert atraumatic needle with bevel/cutting edge oriented to split fibres longitudinally, angle slightly cephalad toward umbilicus. Feel for “pop” through ligamentum flavum and dura. Remove stylet, check for CSF, attach manometer for opening pressure, then collect ~10 mL across numbered bottles (1 → 4 sequential — useful to differentiate SAH from traumatic tap). Replace stylet before withdrawing needle. |
| Post-procedure | Dressing, dispose sharps, lay patient flat 30 min, simple analgesia, advise re: post-LP headache and to return if neurology or fever. Samples — MC&S, protein, glucose (paired blood), xanthochromia (if SAH suspected, ≥12 h post-headache onset). |
| Common pitfalls | Using a cutting Quincke needle (atraumatic now standard, reduces post-LP headache). Forgetting paired blood glucose. Not numbering bottles sequentially. Forgetting xanthochromia. Mis-stating contraindications (anticoagulants and platelets <50 are the ones examiners probe). |
Seldinger chest drain: equipment, sequence and pitfalls
| Stage | What to say or do |
|---|---|
| Equipment | Seldinger chest drain kit (12F suitable for most adult indications, larger for haemothorax/trauma — open drain via blunt dissection); chlorhexidine 2% in 70% alcohol; sterile drape, gown, gloves; 1% lidocaine (max 3 mg/kg) with green and blue needles, 10 mL syringes ×2; scalpel; underwater seal drainage bottle with sterile water filled to mark; non-absorbable 0 or 1/0 silk straight-needle suture; transparent dressing; ultrasound machine with sterile probe sheath (mandatory for effusions, not for pneumothorax). |
| Pre-procedure | Indications (large symptomatic pneumothorax, traumatic pneumothorax/haemothorax, ventilated patient, large or malignant effusion, empyema). Check FBC, clotting — INR <1.5, platelets >50. Review imaging. Written consent. Pre-procedure checklist (NatSSIPs). Mark side. |
| Positioning | Semi-reclined at 45°, hand behind head on side of insertion — or sitting forward over a table. |
| Landmarks | Triangle of safety — anterior border latissimus dorsi, lateral border pectoralis major, line through 5th intercostal space (nipple level in male), apex below axilla. Aim above the rib to avoid the neurovascular bundle. |
| Sequence | Ultrasound mark for effusion. Asepsis, drape, LA skin and down to pleura, aspirating as you go — stop when air or fluid returns, note depth. Introducer needle along same tract, aspirate, advance 0.5 cm past first return. Thumb on hub, pass guidewire (up for pneumothorax, down for effusion), remove needle, small scalpel nick beside wire, pass dilator, then drain over wire. Remove wire. Attach 3-way tap, then underwater seal. Confirm swing/bubble. Secure with suture wrapped around drain, transparent dressing — no purse-string. |
| Post-procedure | Post-insertion CXR — drain position, lung re-expansion, exclude misplacement. Analgesia, prescribe. Drain on free drainage (cap at 1.5 L in 24 h for large effusion — re-expansion pulmonary oedema risk). Document indication, drain size, depth, suture, fluid drained, complications. Samples — pleural fluid for protein, LDH, pH, glucose, MC&S (plus blood culture bottles for empyema), cytology (≥30 mL). |
| Common pitfalls | Forgetting ultrasound for effusion (BTS standard). Drain below 5th ICS — risk of liver/spleen. No suture/dressing plan. Forgetting post-insertion CXR. Quoting wrong max-drainage volume. |
Arterial blood gas and arterial line: equipment, sequence and pitfalls
| Stage | What to say or do |
|---|---|
| Equipment (ABG) | Pre-heparinised ABG syringe with needle (23G); alcohol wipe; gauze; sharps bin; ice if there will be a delay to analysis. For arterial line — 20G arterial cannula or Seldinger arterial line kit, pressure transducer set, flush bag (0.9% saline 500 mL with 500 units heparin per local policy), monitor, suture or securement dressing, sterile drape, gloves. |
| Pre-procedure | Indications (respiratory failure, sepsis, DKA, shock, post-arrest, monitoring). Modified Allen’s test for radial — confirm ulnar collateral flow. Check anticoagulation. Consent — verbal for ABG, written for arterial line. |
| Positioning | Wrist extended 30°, supported on a rolled towel. Palpate the radial pulse 1–2 cm proximal to wrist crease. |
| Sequence (ABG) | Clean skin, palpate pulse with index and middle finger, insert at 30–45° bevel up against the direction of flow, advance until flash, allow self-fill 1–2 mL, withdraw, immediate firm pressure for 3–5 min (longer if anticoagulated), expel air bubbles, cap, label, send. For art line — Seldinger or transfixion technique, secure with suture, level transducer to mid-axilla, zero, square-wave test. |
| Post-procedure | Document time of sample relative to FiO₂. Interpret on the bench — pH, pCO₂, HCO₃, BE, lactate, PaO₂:FiO₂ ratio. Safety-net for haematoma, distal ischaemia. |
| Common pitfalls | Forgetting Allen’s test. Inadequate post-puncture pressure. Failing to state FiO₂ at sampling. Not interpreting the gas at the end — examiners often follow with “and what does this gas show?” |
Knee joint aspiration: equipment, sequence and pitfalls
| Stage | What to say or do |
|---|---|
| Equipment | Sterile dressing pack, gloves, drape; chlorhexidine 2%; 1% lidocaine 5–10 mL with 25G needle for skin; 20–21G (green) needle on a 20 mL syringe for aspiration (larger 18G for thick purulent fluid); sample pots — universal container for microscopy, culture and sensitivity, crystals (no preservative — fluoride/oxalate destroys crystals), and a blood-culture bottle for low-volume purulent fluid; sharps bin; dressing. |
| Pre-procedure | Indication — diagnostic (septic arthritis vs crystal arthropathy vs haemarthrosis), therapeutic decompression of large effusion. Contraindications — overlying cellulitis, prosthetic joint (orthopaedic referral), severe coagulopathy. Consent. |
| Positioning | Patient supine, knee extended or slightly flexed (~15°) on a rolled towel, quadriceps relaxed. |
| Landmarks | Supero-lateral approach: 1 cm above and 1 cm lateral to the supero-lateral corner of the patella, aim toward the intercondylar notch. Medial approach acceptable. Avoid the patellar tendon. |
| Sequence | Asepsis, drape, skin LA bleb and infiltrate down to capsule. Insert green needle, advance while aspirating, redirect gently if dry. Aspirate to dryness if therapeutic. Compress the supra-patellar pouch with the free hand to milk fluid toward the needle. |
| Post-procedure | Dressing, advise rest 24 h, simple analgesia, safety-net (worsening pain, swelling, fever — return). Samples — MC&S urgently, polarised light microscopy for crystals (urate negatively birefringent needles, CPPD weakly positive rhomboids), cell count. Document fluid colour and volume. |
| Common pitfalls | Sending fluid in fluoride-oxalate (destroys crystals). Aspirating through cellulitis. Forgetting to mention prosthetic joints go to orthopaedics. Failing to interpret aspirate at the end — turbid yellow with WCC >50,000 = septic until proven otherwise. |
Fascia iliaca block: equipment, sequence and pitfalls
| Stage | What to say or do |
|---|---|
| Equipment | Sterile dressing pack, drape, gloves; chlorhexidine 2%; long blunt block needle (Tuohy-style 100 mm for landmark) or short-bevel block needle for ultrasound; 20 mL syringe; 0.25% levobupivacaine or 0.5% (calculate max dose — levobupivacaine 2 mg/kg lean body weight, typical 30 mL of 0.25% in a 70 kg adult); 10 mL 0.9% saline for hydrodissection; sharps bin; full monitoring (SpO₂, ECG, NIBP); intralipid 20% available; resuscitation trolley nearby. |
| Pre-procedure | Indication — neck of femur fracture (RCEM standard within 1 h of arrival), other proximal femoral or hip injury, knee surgery analgesia. Contraindications — refusal, local infection, allergy, anticoagulation per local policy, previous femoral bypass. Consent — explain local anaesthetic toxicity signs (perioral tingling, metallic taste, tinnitus, seizures, arrhythmia). |
| Positioning | Supine, leg slightly externally rotated. Landmark — junction of lateral and middle third of a line between ASIS and pubic tubercle, then 1–2 cm caudal. Identify femoral artery medially — must stay lateral to it. |
| Sequence (landmark) | Monitoring on, full asepsis. LA skin bleb. Insert blunt needle perpendicular, feel two “pops” — fascia lata then fascia iliaca. Aspirate (negative for blood) then inject 1–2 mL test dose, observe for resistance and patient reaction, then inject remaining LA in 5 mL aliquots with aspiration between each.
Ultrasound-guided is preferred where available — in-plane lateral-to-medial approach, identify fascia iliaca above iliopsoas, deposit LA under the fascia and watch it spread medially. |
| Post-procedure | Monitor for 30 min for LA toxicity. Document time, drug, dose, volume, side, ultrasound use. Reassess pain score at 30 min. Safety-net the patient and nursing team for LAST symptoms. Intralipid 20% — initial bolus 1.5 mL/kg, then infusion 15 mL/kg/h per AAGBI guidance. |
| Common pitfalls | Not calculating max LA dose by lean body weight. Forgetting LAST management plan and intralipid location. Injecting medial to the femoral artery. Skipping aspiration between aliquots. Not asking about anticoagulation. |
Synchronised DC cardioversion and defibrillation: equipment, sequence and pitfalls
| Stage | What to say or do |
|---|---|
| Equipment | Defibrillator with sync function and adhesive defib pads (preferred over paddles); ECG monitoring; airway trolley with bag-valve-mask, suction, anaesthetic and intubation kit; sedation drugs (typically midazolam + fentanyl, or propofol with anaesthetic support, ketamine); reversal agents (flumazenil, naloxone); IV access ×2 with running fluid; oxygen 15 L via non-rebreathe; trained assistant; full monitoring (ECG, SpO₂, NIBP, capnography if sedating). |
| Pre-procedure | Indication — unstable tachyarrhythmia with adverse features (shock, syncope, ischaemia, heart failure) per ALS, or elective for stable AF/flutter. Contraindications/precautions — digoxin toxicity, hypokalaemia, untreated thyroid disease, unanticoagulated AF >48 h (TOE or anticoagulate first). Consent if conscious. Fasted ideally. |
| Positioning | Supine, pads in antero-lateral position (below right clavicle and over cardiac apex/V6) — antero-posterior if AF and first attempt unsuccessful, or if pacemaker in situ (keep pad >8 cm from device). |
| Sequence | Confirm rhythm. Attach pads, monitoring, oxygen. Sedate with anaesthetic input (procedural sedation). Press SYNC — confirm marker on R wave. Charge — biphasic 120–150 J for AF (escalating), 70–120 J for atrial flutter or SVT. “Stand clear, oxygen away, shocking now” — visual sweep around bed, ensure no contact. Press and hold discharge buttons until shock delivered (sync has a delay). Reassess rhythm and pulse. Repeat synchronised shock if needed, escalating energy. Re-press sync between every shock (it resets).
For unsynchronised defibrillation (VF/pulseless VT) — 150–200 J biphasic, no sync, immediate CPR for 2 min after shock. |
| Post-procedure | Recovery position if sedated, continue monitoring until awake. 12-lead ECG. Document rhythm, energies used, sedation, complications, pad position. Plan for anticoagulation in AF. |
| Common pitfalls | Forgetting to press SYNC (or forgetting to re-press between shocks — this is the classic OSCE fail). Not removing oxygen. Inadequate sedation plan. Not knowing antero-posterior pad position for refractory AF. Confusing sync energies with defibrillation energies. |
How do I handle the “verbalise it” problem on mannikin stations?
Most procedure stations use a partial-task trainer (chest, knee, lumbar spine, arm) and a simulated patient. You can’t actually feel landmarks, you can’t get true CSF, and the kit may be incomplete. The trick:
For more on this, see our guide to common OSCE station fails.
- Verbalise everything you would normally do silently. “I’m now palpating Tuffier’s line at the level of the iliac crests.” “I would now apply ultrasound and confirm a safe pleural pocket.”
- Treat the examiner as an assistant — “Please could you open the drain pack onto my sterile field.”
- If kit is missing, say so — “I would normally use 2% chlorhexidine; this isn’t available so I’d use the next available antiseptic.”
- Maintain asepsis even on the mannikin. Touching your contaminated glove on a non-sterile surface is a clear fail point even when the model is plastic.
How do I avoid losing easy marks on local anaesthetic toxicity?
This catches candidates on fascia iliaca, Bier’s block, haematoma block and wound infiltration stations. Examiners want you to:
- Name the drug, concentration, and calculated maximum dose by lean body weight (lidocaine 3 mg/kg plain, 7 mg/kg with adrenaline; levobupivacaine 2 mg/kg).
- Aspirate before every injection.
- State the early signs of LAST — perioral tingling, metallic taste, tinnitus, light-headedness, then CNS (seizures, coma) and CVS (arrhythmia, arrest).
- State the treatment — stop injection, 100% O₂, ABC, intralipid 20% (1.5 mL/kg bolus, then 15 mL/kg/h infusion, max 12 mL/kg total), call for anaesthetic and ITU help, treat arrhythmias per ALS but avoid lidocaine.
- Know where the intralipid is in your real department, and say so.
What’s the single most common reason candidates fail procedure stations?
Time mismanagement on the post-procedure section. Examiners report repeatedly that strong candidates do an excellent technical procedure, then run out of time before they get to:
- Confirmation imaging or test (CXR post chest drain, manometer reading post LP, aspirate interpretation post joint tap).
- Samples — what bottles, what tests, where they go.
- Aftercare — analgesia, monitoring, position, what to watch for.
- Safety-net to nursing staff and patient.
- Documentation — name, GMC number, indication, consent, technique, complications, plan, follow-up.
If you sense the bell coming and you’ve not done the procedure cleanly, stop and deliver the post-procedure plan in shorthand. You get more marks for “post-procedure I would request a CXR, prescribe analgesia, hand over to nursing, document indication and complications, and send pleural fluid for protein, LDH, pH and MC&S” than for a perfect final stitch.
How should I structure my final two weeks of revision?
- Week –2: Read the SLO 6 list, watch one video per procedure (RCEMLearning, St Mungo’s, Geeky Medics, Oxford Medical Education). Write your own one-page checklist for each of the six core procedures here.
- Week –2: Borrow a trainer from your meded centre. Run each procedure end-to-end with a peer reading the marksheet, timing 7 min.
- Week –1: Drill the generic opening (intro–consent–kit–pause) until it takes <60 s. Drill LAST management, max LA doses, sync vs defib energies.
- Final 48 h: Don’t learn new procedures. Re-read your own checklists. Rehearse the post-procedure plan out loud.
FAQs
How many procedure stations are in the MRCEM OSCE?
The exam is 16 live stations plus rest stations. SLO 6 must be covered, but the number of pure procedure stations varies by sitting — typically 2–4 formal procedures on trainers, plus procedural elements inside resuscitation or paediatric stations. Check current RCEM exam regulations for your sitting.
What’s the difference between Seldinger and open chest drain?
Seldinger uses a guidewire over a fine introducer needle and a dilator — preferred for effusions and elective pneumothorax. Open (surgical) chest drain uses blunt dissection and a finger sweep, then a larger-bore drain — preferred in trauma (haemothorax, tension) where bore and speed matter more than comfort.
Do I need to know ultrasound for procedure stations?
Yes — ultrasound is mandatory for thoracic procedures involving fluid (BTS) and strongly recommended for vascular access and fascia iliaca blocks. You won’t usually be asked to drive the machine, but verbalise its use in the sequence.
What antiseptic for which procedure?
2% chlorhexidine in 70% alcohol for chest drain, joint aspiration, central/arterial line and blocks. 0.5% chlorhexidine in 70% alcohol for LP — higher concentrations are neurotoxic near the dura. Iodine acceptable if chlorhexidine allergy.
How do I calculate max local anaesthetic dose?
By lean body weight. Lidocaine plain 3 mg/kg, with adrenaline 7 mg/kg, levobupivacaine 2 mg/kg. 1% solution = 10 mg/mL. So 1% lidocaine in a 70 kg adult — max 210 mg = 21 mL.
What’s the right needle for an LP?
22G atraumatic (pencil-point, e.g. Sprotte or Whitacre). Multiple trials and a 2018 BMJ practice guideline show lower post-LP headache vs cutting Quincke needles. Say so on the station.
How long do I compress after an ABG?
3–5 minutes, longer if anticoagulated or after an art-line removal.
Where exactly is the triangle of safety?
Anterior — lateral border of pectoralis major. Posterior — lateral border of latissimus dorsi. Inferior — horizontal line at the 5th intercostal space (nipple in men). Apex below the axilla. Insert above the rib.
What samples after joint aspiration?
Urgent MC&S in a plain universal container. Crystals in a plain container (never fluoride-oxalate — destroys crystals). Cell count if available. Send blood cultures and CRP/WCC in parallel if septic arthritis suspected.
Antibiotic prophylaxis before chest drain?
Not routinely for elective drains. In penetrating trauma BTS supports prophylactic antibiotics per local policy (single dose cefazolin or co-amoxiclav typical). Defer to your trust SOP.
Safe max drainage from a large pleural effusion in 24 h?
1.0–1.5 litres in 24 h, or 400 mL per 8 h, to avoid re-expansion pulmonary oedema. Drain slowly through a partly-clamped 3-way tap.
What if I’ve never actually done the procedure?
You can still pass. The examiner scores the marksheet, not your logbook. Run the generic structure cleanly, verbalise your kit, demonstrate asepsis, perform a recognisable approximation, and deliver the post-procedure plan in full. Where you cannot pass is by skipping consent, asepsis, or the post-procedure plan.
Next step
For full marksheet-aligned procedure walkthroughs, scored mock OSCE stations with examiner feedback, and the rest of the SLO 6 syllabus broken down procedure by procedure, see the MRCEM OSCE prep course at emfinalexams.com.
Facts last verified . Always cross-check current RCEM exam regulations, BTS, AAGBI, RCEM Best Practice and your local trust SOPs before performing any procedure on a patient.
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