Anastomotic Leak in the CST Interview
How to answer the post-operative confusion / anastomotic leak scenario in the CST interview: why you never prescribe sedation over the phone, Sepsis Six, and SBAR escalation.
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The night-shift phone call asking you to prescribe a sleeping tablet for a confused post-operative patient is one of the sharpest traps in the CST clinical bank. The entire station turns on your first sentence: new confusion after surgery is a red flag, not a nuisance.
How the scenario tends to open
A typical stem: day five after an anterior resection for rectal cancer, an elderly man becomes agitated and confused overnight, and the ward asks you for night sedation over the phone. Day five after a rectal anastomosis is not an accident — it is peak territory for an anastomotic leak presenting as sepsis-driven delirium.
The approach that scores
Decline the sedation, say why, and go: sedating an unassessed patient can mask deterioration and delay the diagnosis. While you head to the ward, ask for fresh observations and a blood glucose, and for staff to keep him safe in the meantime.
At the bedside, run a structured A–E, then hunt the source: abdomen, wound sites, chest, catheter. Screen the other causes of delirium actively — hypoxia, hypoglycaemia, retention, medication, alcohol withdrawal, pain — while keeping the leak at the top of your list.
- Investigations: full blood count, renal profile, CRP, liver function, coagulation and group and save, venous gas with lactate, and blood cultures before antibiotics; add a chest X-ray and urine culture without losing focus on the abdomen.
- Start the Sepsis Six within the hour: oxygen, cultures, IV antibiotics per local guidelines, fluids, lactate, urine output monitoring. Keep him nil by mouth.
- Escalate urgently to the registrar with SBAR, naming your concern — suspected anastomotic leak — and anticipating an urgent CT and a possible return to theatre.
- State that three in the morning changes nothing: if the registrar is unavailable, you call the consultant.
Where candidates lose marks
Prescribing the sleeping tablet fails the station in the first breath. Less obviously, treating "confusion screen" and "sepsis workup" as separate exercises wastes time — the strong answer runs them together. Marks also sit in anticipation: a leak may mean laparotomy and a stoma, critical care outreach should be involved early, and the family will need updating.
Rehearse it
Reading about anastomotic leak is the easy half. Rehearse this exact scenario out loud, on the clock, with an AI examiner — this scenario is in Reviva’s library, with feedback marked the way the panel marks. Or start with the wider format in the cst clinical scenarios guide.
Frequently asked questions
- Why is new confusion in a post-operative patient a red flag?
- Because delirium is often the first sign of something serious — at day five after bowel surgery, sepsis from an anastomotic leak until proven otherwise. Sedating it without assessment masks deterioration.
- What is the Sepsis Six?
- Oxygen, blood cultures, IV antibiotics, IV fluids, lactate measurement, and urine output monitoring — delivered within the hour for suspected sepsis.
- Which patients are at higher risk of anastomotic leak?
- Rectal (low) anastomoses carry a higher risk than more proximal joins; steroids, poor nutrition, and smoking add to it. Mentioning risk stratification is a mark of a stronger answer, not a requirement.
Sources. Grounded in the standard recognition and management of anastomotic leak and post-operative delirium as rehearsed in Reviva’s CST clinical scenario. Educational only — follow your local policies and current national guidance.