'It hurts at the line' — suspected central-line-associated bloodstream infection structured encounter

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 surveillance definition, recognition, paired cultures and empiric therapy, the line-removal decision, antimicrobial de-escalation, communication and safe handover. [3] [12]

Candidate instructions

You are the paediatric registrar called to an acute assessment room. Recognise and define Aria's suspected central-line-associated bloodstream infection. Take paired cultures before antibiotics and start empiric therapy. Decide on the line using the removal thresholds. Speak directly to Aria and her mother. Call senior and infection-prevention support early. Finish with a structured handover, a de-escalation plan and a family safety-net. Do not perform painful manoeuvres on the actor; say what you would assess or do instead. [3] [12]

Room setup and observable starting state

The encounter. Aria is 6 and has a long-term central line for parenteral nutrition. She has had two days of fever and now rigors during a line flush. She is seated with her mother and points to the line saying it hurts. [1] [3]

What is visible before touch. Aria is flushed and less interactive than her mother reports as usual. She points to the line site. These are abnormalities in appearance and reported circulation consistent with a device infection. The candidate should describe the signs, define the syndrome, call for help, and begin the workup. [3] [12]

Simulation safety. Aria remains seated. Cards or the assessor supply observations, examination findings and culture results. No painful or distressing manoeuvre is performed on the actor. [12]

Actor cues

Child actor

• When the candidate uses Aria's name and simple words, look towards them briefly, then point to the line and look away. [3]

Caregiver actor

• Begin by naming the line and the fever. If asked what changed, answer: "She usually bounces back from her line changes. This time the fever hasn't settled, she shivered through the flush, and she keeps saying the line hurts." [1] [3]

Assessor cues and clinical data

Give each finding only when the candidate reaches that step or asks for it. Interpret observations using Aria's exact age, measurement conditions, trend and active local chart. The Royal Children's Hospital Melbourne intravenous-access guidance is one example pathway; it is not a universal rule. [3] [12]

The NHSN protocol supports the surveillance definition. This encounter gives no universal duration or specific dose; the candidate should follow the active local pathway, use age- and weight-appropriate equipment, and judge the response after every intervention. [3]

Reassessment cue within the same encounter

Once the candidate has taken cultures and given the first antibiotic, say: "After 48 hours she is afebrile and well, the site is clean, and both cultures grow a coagulase-negative staphylococcus with a short line-versus-peripheral time-to-positivity differential." This is not a second case. The candidate should interpret the differential time to positivity as supporting an intraluminal source, decide whether to remove or retain the line in a clinically stable child with clearing bacteraemia, de-escalate to the narrowest effective agent, and define the surveillance and stewardship plan. [3] [12]

Expected candidate sequence

1. Recognise and define. Describe the signs, state the CLABSI surveillance definition with the time and device criteria, and state that the child is treated on clinical grounds while surveillance is adjudicated. Call senior and infection-prevention support now. [3] [12]
2. Sample and treat. Take paired peripheral and line cultures before antibiotics, send inflammatory markers, and start empiric antistaphylococcal cover. State the line-removal thresholds. [3]
3. Interpret the organism. Use the differential time to positivity and the clinical course to decide on the line, de-escalate to the narrowest effective agent, and define a duration. [3] [12]
4. Hand over and prevent. Give a structured handover, state the prevention bundle, name device and antimicrobial stewardship together, and provide a written family safety-net for fever. [4] [12]

MedVellum formative marking domains

This educational rubric has 10 domains scored 0–3, giving a MedVellum formative total of 30. Score 0 for omitted or unsafe, 1 for named but incomplete, 2 for clear and safe, and 3 for integrated, prioritised and reassessed. This is not an official board mark or pass standard. Feedback should identify the first unsafe step, not only the total. [3] [12]

Critical fails

Any item below overrides a reassuring formative total because it creates immediate avoidable risk. [3] [9]

• Delays cultures or antibiotics while awaiting surveillance adjudication.
• Attempts to salvage a line in sepsis, a tunnel infection, or with Staphylococcus aureus, Pseudomonas, or Candida.
• Treats catheter-associated asymptomatic bacteriuria or tests an asymptomatic child for C. difficile without diarrhoea.

Examiner prompts

Use as few neutral prompts as possible. A prompted behaviour can receive no more than 2/3 in the affected MedVellum formative domain. This is an educational feedback convention, not an official examination rule. [3] [12]

1. "What syndrome does Aria have, and how do you define it?"
2. "Tell me your line-removal thresholds."
3. "How does the differential time to positivity help you?"
4. "What should have prevented this, and what is the family safety-net?"

Model performance

Aria has suspected central-line-associated bloodstream infection — a laboratory-confirmed bloodstream infection with a central line in place for more than two days and no other source. I take paired peripheral and line cultures before antibiotics, start empiric antistaphylococcal cover, and set removal thresholds for sepsis, tunnel infection, persisting bacteraemia, and high-risk organisms. I use the short line-versus-peripheral differential time to positivity to confirm an intraluminal source, and in a stable child with clearing coagulase-negative staphylococcal bacteraemia I weigh line removal against retention with documented reassessment, de-escalate to the narrowest effective agent, and define the duration. I state the multimodal prevention bundle, steward the device and the antimicrobial together, give a structured handover, and provide a written family safety-net for fever. [1] [3] [12]

Disposition and safety-net standard for this encounter

Aria is not safe for discharge until afebrile, clinically well, with documented clearance of bacteraemia and a clear antimicrobial and device plan. A brief improvement does not make discharge safe. The team states the next sign of failure, the action, the owner, and the plan if the family lives remotely. Handover includes the diagnosis, pending results, the line decision and specific warning changes. Check understanding directly with Aria's mother and give a written safety-net for fever. [3] [12]