Paediatric sepsis: diagnosis, antimicrobial treatment and source control — branching viva

Station status

This is one MedVellum formative branching structured oral. The prompts and performance descriptions are educational feedback tools; they are not an official college examination format, mark allocation, pass score or reproduced station. The viva assesses Phoenix-criteria classification, the first-hour bundle, fluid and vasoactive escalation with reassessment, source control, and safe retrieval. [3] [11]

Stage 1 — Recognition and classification

Examiner. A four-year-old presents with two days of fever and cough. She is now less interactive, mottled, and cool peripherally with a 4-second capillary refill. Heart rate 150, blood pressure 92/50, respiratory rate 36, oliguric, lactate 4.2 mmol/L. [1] [12]

What the candidate must do. Recognise sepsis with suspected infection (probable pneumonia) and life-threatening organ dysfunction. Apply the Phoenix criteria: cardiovascular dysfunction (impaired perfusion, oliguria, raised lactate) gives at least one point, so the child meets both sepsis and septic shock. State that a normal-range blood pressure does not exclude shock because children are hypotensive late. [1] [2]

Examiner branch. "Why did we move away from SIRS?" The candidate should explain that SIRS was too sensitive — many well children met it and some dying children did not — and that the Phoenix criteria were validated on more than 700,000 hospitalised children and discriminate mortality better. [1] [2]

Stage 2 — The first-hour bundle

Examiner. "Take me through your first hour." [3]

What the candidate must do. State the bundle runs in parallel: assign a leader and call for help; cultures before antibiotics only if it does not delay the first dose; a broad-spectrum, weight-based antibiotic within one hour (third-generation cephalosporin, plus vancomycin if resistant organisms are possible); a 10 mL/kg crystalloid aliquot with immediate reassessment; and early vasoactives rather than waiting for refractory shock. [3] [11]

Examiner branch on fluids. "How does the fluid evidence shape your approach?" The candidate should cite FEAST (boluses increased mortality in an African population without intensive-care rescue) and the Fluids in Shock pilot (restricted bolus feasible), and conclude that aliquots, reassessment and a ceiling — not a target — are the safe discipline. [8] [9]

Stage 3 — Deterioration and escalation

Examiner. "After two aliquots she now has hepatomegaly, crackles at both bases, and her lactate is 5.0. Blood pressure is 80/45." [3] [12]

What the candidate must do. Recognise fluid intolerance and refractory shock. Stop further boluses, start or escalate the vasoactive (this is cold shock, so adrenaline is first-line; add noradrenaline if vasodilatory), request early PICU involvement, and consider stress-dose hydrocortisone for catecholamine-resistant shock. Reassess after each change. [3] [9]

Examiner branch. "Balanced or saline?" The candidate should state that the PRoMPT BOLUS trial found balanced and 0.9% saline equivalent in children with septic shock, so either is acceptable per local protocol, and that the discipline of reassessment matters more than the fluid type. [16]

Stage 4 — Source control, retrieval and handover

Examiner. "She is intubated and on adrenaline. How do you complete definitive care?" [11] [12]

What the candidate must do. Identify and control the source — chest imaging for empyema and drainage if present; de-escalate the antimicrobial to the organism and sensitivities as they return; and engage retrieval before local capability is exceeded. The handover should carry the diagnosis, Phoenix score, timed interventions and responses, the working source, pending cultures and the specific deterioration plan. [11] [12]

Examiner branch on equity. "She lives three hours from the tertiary centre." The candidate should weigh distance, escort skill, transport delay and family communication, and note that regional and disadvantaged children are recognised and treated later, so earlier escalation is justified. [13]

MedVellum formative marking domains

This educational rubric has six domains scored 0–3, giving a MedVellum formative total of 18. 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. [3] [11]

Critical fails

Any item below overrides a reassuring formative total because it creates immediate avoidable risk. [3] [8]

• Delays the antibiotic beyond one hour for imaging or an unsafe lumbar puncture.
• Continues fluid boluses past the ceiling despite signs of fluid intolerance.
• Waits for refractory shock before starting vasoactives.
• Omits source control or retrieval planning.

Model performance

"This child has suspected infection with life-threatening organ dysfunction — a Phoenix cardiovascular score from her impaired perfusion, oliguria and lactate — so she has septic shock. I call for help, take cultures before antibiotics only if it does not delay the dose, give a broad-spectrum weight-based antibiotic within one hour, and give a 10 mL/kg aliquot with immediate reassessment. When she shows hepatomegaly and crackles with a rising lactate, I stop fluids, start adrenaline for cold shock, involve PICU early, and consider hydrocortisone for catecholamine-resistant shock. I control the source by imaging and draining any empyema, de-escalate antibiotics to the organism, retrieve before local capability is exceeded, and hand over the diagnosis, timed interventions, pending cultures and deterioration plan." [1] [3] [12]