Read the strip, choose the antidote — cardiotoxic and psychotropic medication poisoning

Station status

This is one MedVellum formative structured clinical encounter. The scoring, prompts and performance descriptions are educational feedback tools. They are not an official college station, timing, mark allocation, pass score or reproduced examination format. The encounter assesses first-impression recognition of a calcium channel blocker toxidrome, the reading of the ECG and the bedside glucose, the choice of weight-based antidote, the avoidance of the sustained-release late-deterioration trap, communication, reassessment, early escalation to retrieval and extracorporeal support, and safeguarding in parallel. [3] [4]

Candidate instructions

You are the paediatric registrar called to the acute assessment room. Assess the child from the doorway and say aloud what you see. Read the ECG and the bedside glucose as the decision points. Choose the decontamination and the weight-based antidote for the calcium channel blocker. Avoid the sustained-release late-deterioration trap. Reassess from A after every action. Call the poisons centre, senior, intensive care or retrieval support early. Run safeguarding alongside urgent care. Finish with a structured handover and disposition plan. Say what you would assess or do; do not perform painful or distressing manoeuvres on the actor. [3]

Room setup and observable starting state

The encounter. Leo is three years old and is supported on the assessment trolley by a grandparent. The grandparent says, "He got into my pill box." Leo is initially alert but quiet, with coolish limbs. An open bottle of sustained-release verapamil is on the trolley beside him; several tablets are missing. The candidate should describe these signs objectively, declare concern, call for help and the poisons centre, and begin the hands-on ABCDE primary survey and the weight-based dose calculation immediately. [4]

Simulation safety. Leo remains on the trolley and is never forcibly positioned. Cards or the assessor supply the respiratory rate, breathing sounds, monitor readings and examination findings. The grandparent does not obstruct urgent care. [4]

Actor cues

Grandparent actor

• Begin with "He got into my pill box." If asked what has changed, answer: "He found my verapamil tablets. I think he ate some about two hours ago. They're the slow kind. He was fine, but he's gone quiet and his hands are cold."

Child actor

• Respond to voice early in the encounter; become sleepier, bradycardic and harder to rouse as the scenario progresses, following the assessor's cue card.

Assessor cues and clinical data

Release findings as the candidate reaches each step. Reward ECG-and-glucose reading and the early use of calcium and high-dose insulin euglycaemic therapy; penalise the assumption that a well-looking phase excludes danger. [3]

A and B — Airway and breathing

Airway is patent and the child is breathing adequately at first. Respiratory rate 24 with good bilateral air entry, oxygen saturation 97 percent on air. Expected strong behaviour: give high-flow oxygen because the child is in cardiotoxic failure; judge effectiveness by air entry, colour and interaction; prepare for the possibility of intubation if the conscious level falls. [4]

C — Circulation

Heart rate drops from 90 to 55 over the encounter, with weak central pulses, a capillary refill of 4 seconds, a blood pressure that falls to 70/40, and cool limbs. Expected strong behaviour: diagnose the circulation state from the whole picture; gain IV or IO access; give isotonic crystalloid in cautious aliquots (the myocardium is depressed); call for retrieval or critical care early because high-dose insulin euglycaemic therapy and possibly ECMO may be needed. [4]

D — Disability

Responds to voice but becomes sleepier; pupils equal and reactive; no seizure. Expected strong behaviour: screen with AVPU; check the bedside glucose now and recognise that a raised glucose supports a calcium channel blocker over a beta-blocker. [4]

E — Exposure

No rash; the abdomen is mildly distended; the open bottle of sustained-release verapamil is on the trolley. Expected strong behaviour: identify the agent and the sustained-release formulation; ask the grandparent how many tablets are missing and the timing; begin safeguarding documentation in parallel; preserve the bottle. [4]

The laboratory release

The bedside glucose is 11 mmol per L. The venous gas shows a mild metabolic acidosis with a lactate of 3.2 mmol per L. The 12-lead ECG shows sinus bradycardia with a normal QRS and a corrected QT at the upper limit of normal. The paracetamol and salicylate levels are pending. Expected strong behaviour: recognise the calcium channel blocker picture from the bradycardia, hypotension and hyperglycaemia; start intravenous calcium (calcium gluconate 10 per cent 0.6 mL per kg or calcium chloride 10 per cent 0.2 mL per kg) and high-dose insulin euglycaemic therapy (1 unit per kg then 0.5 to 1 unit per kg per hour with dextrose); check glucose and potassium hourly; add vasopressors; prepare lipid emulsion. [3] [4]

Escalation event — the late deterioration

Over the next two hours, despite calcium and a rising insulin infusion, the blood pressure remains low and the lactate rises. The team questions whether to stop. Expected strong behaviour: recognise that this is the sustained-release late-deterioration pattern and that the response to high-dose insulin builds over 15 to 45 minutes; escalate the insulin infusion within the range; add lipid emulsion; activate veno-arterial ECMO early; do not be reassured by transient improvement and do not cease therapy prematurely. [6]

Weight and escalation

The candidate must obtain a working weight for drug and device sizing. Expected strong behaviour: use a measured weight if available immediately; otherwise document a working weight from a recent reliable value, a credible family estimate, or the trained length-and-habitus tool; use the local paediatric cognitive aid and the poisons centre for each weight-based dose. Call retrieval early for a child who may need ECMO, ventilation or intensive care unavailable locally. [4]

Marking domains

Debrief prompts

• What bedside finding discriminated the calcium channel blocker from a beta-blocker, and how did it change the plan?
• Why is high-dose insulin euglycaemic therapy the key therapy here rather than escalating inotropes alone?
• How did the sustained-release formulation change the observation and the escalation plan?
• At what point would you activate extracorporeal support, and why early?