Ruptured AAA in the CST Interview
How to answer a ruptured abdominal aortic aneurysm scenario in the CST interview: parallel escalation, permissive hypotension, and the unstable-patient imaging rule.
On this page
The collapsed, shocked older man with abdominal and back pain is the CST scenario where sequencing matters most: the examiner is listening for escalation that happens in parallel with assessment, not after it.
How the scenario tends to open
A typical stem: a septuagenarian hypertensive smoker collapses with sudden severe abdominal and back pain radiating to the loin; he arrives pale, sweaty, tachycardic, and hypotensive. The loin radiation is a deliberate trap — renal colic in an older patient is a ruptured aneurysm until proven otherwise.
The approach that scores
Two sentences transform this answer. First: I am assuming a ruptured aneurysm and will manage it as one. Second: I would escalate in parallel — vascular registrar and consultant, anaesthetics, and theatres are informed while I assess, because what determines survival is how quickly the aorta is controlled in theatre, not the completeness of my workup.
- A–E assessment with two large-bore cannulae; examine for a pulsatile, expansile mass.
- Resuscitate cautiously — permissive hypotension: target a conscious patient with a palpable pulse, not a normal blood pressure, because overfilling can restart the bleeding. Reach for blood products early instead of litres of crystalloid.
- Send bloods with a six-unit crossmatch and activate the major haemorrhage protocol.
- State the imaging rule: an unstable patient goes to theatre, not the scanner; CT angiography is reserved for someone with enough stability that the vascular team can plan the repair — and it is their call.
- Coordinate: keep the emergency department, theatres, and blood bank aligned; delegate tasks; document times and decisions.
Where candidates lose marks
The classic failures are labelling it renal colic, resuscitating to a "normal" blood pressure, and sending an unstable patient to CT. A subtler one is serial escalation — finishing the entire assessment before picking up the phone. If asked what you would say to the family, be honest and compassionate about severity, ideally alongside a senior; mortality is high even with everything done right.
Rehearse it
Reading about ruptured aaa 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
- What is permissive hypotension in a ruptured AAA?
- Deliberately accepting a lower-than-normal blood pressure — targeting a conscious patient with a palpable central pulse — because aggressive fluid resuscitation can dislodge clot and restart catastrophic bleeding.
- Does a ruptured AAA need a CT scan?
- Only if the patient is stable enough for repair planning, and that decision sits with the vascular team. The rule the examiner wants to hear: unstable patients go to theatre, not the scanner.
- Why does the ruptured AAA scenario reward "parallel" escalation?
- Because survival is determined by time to surgical control of the aorta. Informing the vascular team, anaesthetics, theatres, and blood bank while you assess shows you understand the physiology of the emergency, not just its checklist.
Sources. Grounded in the standard emergency management of ruptured abdominal aortic aneurysm as rehearsed in Reviva’s CST clinical scenario. Educational only — follow your local policies and current national guidance.