Branching cross-examination

This is a MedVellum formative viva. It is not an official RACP, MRCPCH, ABP, ACGME or RCPSC station, mark scheme, duration or pass standard. Release each update only after the candidate states the failing system, the immediate action and the reassessment endpoint. [6] [11]

Candidate brief

You are the senior paediatric clinician leading a regional trauma team. Speak as you would during resuscitation. Control catastrophic haemorrhage before airway work, protect the cervical spine, treat each threat as you find it, state the change you expect from each action, and say what you will reassess. This is one continuous case. Each escalation branch leads to the next update. [6]

Question 1 — Pre-alert, team and the first 60 seconds

Stimulus update. Pre-hospital teams call a trauma alert: a nine-year-old, restrained rear passenger, high-speed crash, death of the driver at the scene, extraction taking 20 minutes. Question: What do you say and do before and at arrival? [6]

Consultant-level model answer. "I confirm the trauma team is activated with named roles — leader, airway, circulation or access, procedures, scribe, and bedside and family nurse. I prepare age- and weight-appropriate airway, access, warming and blood-bank equipment. At arrival I take a structured handover, then run <C>ABCDE treating each threat as found. Stabilisation comes before the full diagnosis." [6]

Probing follow-up. "Why is the death of another occupant relevant?" A strong answer is: "Mechanism predicts injury severity. A death in the same vehicle, high speed, and prolonged extraction all lower my threshold for activation, imaging and senior involvement, even if the child looks compensated on arrival." [11] [6]

Common weak answer. "I will take a full history and examine the child before doing anything." This delays resuscitation in a high-risk child and inverts the order: handover, primary survey, then secondary assessment. [6]

Escalation branch. If the candidate activates the team and starts <C>ABCDE, release the survey data in Question 2. If they anchor on a diagnosis, ask which threat they will treat first. [6]

Question 2 — Catastrophic haemorrhage and the survey data

Stimulus update. There is an open femoral wound with brisk bleeding and a seat-belt mark across the abdomen. Heart rate is 140, central pulses are weak, capillary refill is 4 seconds, blood pressure is low-normal, and the child responds to voice. Question: Lead the next five minutes. What improvement do you expect from each action? [8] [6]

Consultant-level model answer. "At <C> I apply direct pressure to the femoral wound and a tourniquet if bleeding is exsanguinating; I do airway work after. At A I maintain manual in-line stabilisation and protect the airway. At B I give high-flow oxygen and assess for tension pneumothorax clinically. At C I confirm shock from the whole picture despite a non-hypotensive blood pressure, gain access, and give weight-based aliquots of 10 to 20 mL per kilogram with early blood, because the seat-belt mark and the physiology suggest intra-abdominal haemorrhage. At D I check pupils and bedside glucose. I expect better pulse quality, warmer skin, a shorter refill, better interaction and stabilising blood pressure after each action, and I reassess from the top after each." [5] [8]

Probing follow-up. "Why not give a litre of fluid?" A strong answer is: "Large crystalloid volumes worsen hypothermia, acidosis and coagulopathy, the lethal triad. I minimise crystalloid, reassess after each aliquot, and move to balanced blood products early in confirmed haemorrhagic shock, with tranexamic acid within 3 hours and active warming." [5]

Common weak answer. "Give oxygen, fluids and antibiotics, then recheck in an hour." This starts a cause-led bundle before controlling the bleeding, gives no action-specific endpoint, and delays reassessment. [8]

Escalation branch. If the candidate controls haemorrhage and gives blood early, reveal in Question 3 that the coagulation and gas results return deranged. If they gave no endpoint, ask how a normal blood pressure could coexist with shock. [5] [8]

Question 3 — The lethal triad is established

Stimulus update. The venous gas shows a base deficit and a pH of 7.2, the international normalised ratio is raised, the core temperature is 34.8 degrees Celsius, and the haemoglobin is falling despite blood. Question: Interpret this and act. [5]

Consultant-level model answer. "The lethal triad of hypothermia, acidosis and coagulopathy is established, and ongoing bleeding is likely. I escalate to a massive transfusion protocol with balanced components at a ratio near 1 to 1 to 1, give tranexamic acid within 3 hours, warm the child actively to a core temperature above 35 degrees Celsius, correct calcium and acid-base, and arrange urgent surgical or interventional control of the source. I reassess haemoglobin, coagulation and lactate throughout, and I keep the brain perfused and oxygenated." [5] [8]

Probing follow-up. "The blood pressure is now 80 systolic in a nine-year-old. Is that acceptable?" A strong answer is: "For a child aged 1 to 10 years a useful lower limit is about 70 plus twice the age in years, so roughly 88 here; 80 is hypotension and an independent predictor of death. I treat it as decompensated shock, continue damage control resuscitation, and move to definitive control of haemorrhage." [8]

Common weak answer. "I will warm the child slowly and recheck the bloods." The triad is self-reinforcing and kills; it needs active rewarming, early blood and source control now, not slow observation. [5]

Escalation branch. If the candidate runs damage control resuscitation correctly, move to Question 4 on imaging and the brain. [5]

Question 4 — Imaging decisions and the brain

Stimulus update. Bleeding is controlled in theatre. The child is now intubated; pupils are equal but the Glasgow Coma Scale before intubation was 8 after a brief seizure. Question: How do you decide on imaging of the head and cervical spine? [1] [2]

Consultant-level model answer. "A Glasgow Coma Scale below 9, a seizure and a high-energy mechanism mean this child needs urgent cranial computed tomography and cervical spine imaging, and neurosurgical referral. In the lower-risk, awake child I would apply the PECARN head-injury rule to identify those who can safely avoid a scan, and the PECARN cervical spine rule to identify those who can avoid imaging after blunt trauma. But this child is not low-risk: I image, and I move her safely with monitoring and escort only because she is now stable enough to transfer." [1] [2]

Probing follow-up. "When would you not scan the head?" A strong answer is: "In a child who meets the PECARN very-low-risk criteria, where the risk of clinically important brain injury is so low that observation without computed tomography is safe. I state the rule and the criteria I am applying." [1]

Common weak answer. "I will scan everything to be safe." Imaging has a cost and a radiation burden; decision rules exist to reduce unnecessary scans without missing serious injury, and they should be applied where the child is low-risk. [1]

Escalation branch. If the candidate applies the rules and protects the brain, move to Question 5 on retrieval and handover. [2]

Question 5 — Retrieval and structured handover

Stimulus update. The regional service cannot provide paediatric intensive care or neurosurgery. Question: Describe your escalation and handover. [6] [11]

Consultant-level model answer. "I called retrieval and the paediatric trauma centre in parallel with resuscitation, before local support was exceeded. I agree the destination, the treatment to continue en route, the escort, the monitoring and blood plan, the contingency for deterioration, and the plan if transfer is delayed. My structured handover transfers identity and working weight, mechanism, current physiology and trend, timed actions and response, the prioritised differential and pending tests, local limits, family and safeguarding information, and the next contingency with its named owner. I keep the family informed and document objectively." [6] [11]

Probing follow-up. "What is the one principle you most want the team to carry forward?" A strong answer is: "Control catastrophic haemorrhage first, run <C>ABCDE treating each threat as found, break the lethal triad, protect the brain, and escalate before local support is exceeded. Reassess from the top after every action." [6]

Common weak answer. "I will wait for the retrieval team before doing anything else." The child needs ongoing reassessment and stabilisation during the wait, with a contingency for deterioration. [11]