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. [8] [9]

Candidate brief

You are the senior paediatric clinician in a rural district emergency department. Speak as you would during resuscitation. Treat immediate threats before the diagnosis is certain, 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. [9]

Question 1 — Doorway and the first 60 seconds

Stimulus update. A parent carries a four-year-old who has been unwell for two days with cough, fever and poor intake. Before you touch the child you see poor tone, little eye contact and a weak response, marked recession with nasal flaring, and mottled limbs. Question: What do you say and do now? [9]

Consultant-level model answer. "I am immediately concerned. The first impression is abnormal: reduced appearance and tone, increased work of breathing, and poor circulation to skin. I call the senior paediatric and resuscitation teams now, name a leader, allocate roles, and bring age- and weight-appropriate equipment and monitoring. I begin the hands-on ABCDE primary survey immediately and will treat each threat as I find it. Stabilisation comes before diagnosis." [9]

Probing follow-up. "Why treat before you diagnose?" A strong answer is: "Because a blocked airway, failing breathing or shock will kill the child before the diagnosis is settled. The ABCDE survey finds and fixes the failing system in the order it kills, and the cause-specific pathway takes over once the immediate threats are controlled. I never stop reassessing." [9]

Common weak answer. "I will take a full history, examine the child and order bloods and a chest X-ray." This delays resuscitation for diagnostic completeness in a visibly critical child, and it inverts the order: first impression, then primary survey, then secondary assessment. [9]

Escalation branch. If the candidate calls for help and starts ABCDE, release the survey data in Question 2. If they anchor on a diagnosis, ask which failing system they will treat first while the work-up proceeds. [9]

Question 2 — The survey data and response endpoints

Stimulus update. Airway is patent but the voice is weak. Respiratory rate is 52 with marked recession and reduced bilateral air entry; oxygen saturation is 90% on air with a reliable waveform. Heart rate is 160, central pulses are weak, capillary refill is 4 seconds, and blood pressure is low-normal. The child responds to voice but cannot sustain interaction. Question: Lead the next five minutes. What improvement do you expect from each action? [1] [9]

Consultant-level model answer. "I take leadership and allocate airway, breathing, circulation, access and family roles. At A I want an airway the child can maintain. At B I give high-flow oxygen because the child is in failure, and I judge effective ventilation by chest rise, air entry, improving colour and interaction, targeting a saturation of 94 to 98% in this previously well child; if breathing remains ineffective I support it with bag and mask. At C I gain access, give fluid in aliquots, and I expect better pulse quality, warmer skin, a shorter refill, better interaction and more urine; I reassess after each aliquot and stop for overload or no benefit. At D I check bedside glucose now and correct a dangerous low immediately." [1] [3] [7] [9]

Probing follow-up. "Why is the saturation alone an unsafe breathing endpoint?" A strong answer is: "I confirm a reliable waveform and check the displayed pulse matches the child, but oximetry does not measure ventilation and may lag or overestimate oxygenation. I therefore reassess air entry, effort, drive, interaction and perfusion alongside the number." [1] [9]

Common weak answer. "Give oxygen, fluids and antibiotics, then repeat observations in an hour." This starts a cause-led bundle before defining the failing system and the shock type, gives no action-specific endpoint, and delays reassessment. [3] [9]

Escalation branch. If the candidate gives several breathing and circulation endpoints, reveal in Question 3 that saturation improves while breathing becomes less effective. If they gave no endpoint, ask how a reassuring monitor could coexist with respiratory failure. [1] [9]

Question 3 — The tiring child

Stimulus update. After oxygen, the saturation rises to 95%, but the child becomes quieter with less recession and noticeably reduced air entry and interaction. Question: Interpret this and act. [1] [9]

Consultant-level model answer. "This is respiratory muscle fatigue and impending failure, not improvement. A quieter chest after marked effort, with reduced air entry and reduced interaction, is failure until proved otherwise. I support ventilation immediately with bag and mask, declare the improvement I expect (better air entry and interaction, not just a number), call airway and critical-care help, and reassess from A. Recovery requires easier breathing together with better air entry and improved interaction." [1] [9]

Probing follow-up. "The parent is relieved the child is breathing more calmly. What do you say?" A strong answer is: "I explain that the child was working very hard and is now tiring, which is more dangerous, not less. I tell the family what we are doing and what to expect, and I keep them informed as we escalate." [9]

Common weak answer. "The child is improving, so I will reduce the oxygen and observe." This mistakes falling effort for recovery and risks collapse. [1] [9]

Escalation branch. If the candidate recognises failure and supports ventilation, release in Question 4 that the child becomes unresponsive with no central pulse. If they reduce support, ask what finding would prove recovery. [9]

Question 4 — When ABCDE becomes advanced life support

Stimulus update. The child becomes unresponsive, with agonal breathing and no central pulse. Question: What now? [9] [10]

Consultant-level model answer. "The child has arrested. I move directly into the paediatric arrest algorithm: high-quality chest compressions, ventilation with oxygen, attach a defibrillator, and establish intraosseous access. The arrest-dose anchors are intravenous or intraosseous adrenaline at 10 micrograms per kilogram (0.1 mL/kg of 1:10,000 adrenaline) every three to five minutes, and defibrillation at 4 joules per kilogram for a shockable rhythm. I do not finish the survey of an arrested child, and I confirm the working weight with the local cognitive aid." [9] [10]

Probing follow-up. "Why intraosseous?" A strong answer is: "Intraosseous access is rapid, reliable and equivalent to intravenous for drug delivery in arrest when intravenous access is delayed; it is the recommended route when the clock is running." [9] [10]

Common weak answer. "I give intramuscular adrenaline 10 micrograms per kilogram." Intramuscular adrenaline is for anaphylaxis, not cardiac arrest; in arrest the route is intravenous or intraosseous. [9]

Escalation branch. If the candidate runs the arrest algorithm correctly, move to Question 5 on retrieval and handover. [9]

Question 5 — Rural retrieval and structured handover

Stimulus update. Return of spontaneous circulation is achieved. The rural hospital has no paediatric intensive care. Question: Describe your escalation and handover. [8] [9]

Consultant-level model answer. "I called retrieval in parallel with resuscitation, before local support was exceeded. I agree the destination, the treatment to continue, the escort and equipment, the expected deterioration, the plan if transfer is delayed, and the monitoring en route. My structured handover transfers identity and working weight, current physiology and trend, timed actions and response, the prioritised differential and pending tests, local limits, family and safeguarding information, and the next contingency and its named owner. I keep the family informed and document objectively." [8] [9]

Probing follow-up. "What is the one principle you most want the team to carry forward?" A strong answer is: "Treat each threat as you find it, state what you expect, reassess from A, and escalate before local support is exceeded. The diagnosis can follow; the failing system cannot wait." [9]

Common weak answer. "I will wait for the retrieval team to arrive before doing anything else." The child needs ongoing reassessment and stabilisation during the wait, with a contingency for deterioration. [9]