Patient safety, human factors and systems thinking — branching viva

Opening (candidate)

My first priority is the child. I would assess and stabilise the airway and breathing using ABCDE, stop the morphine infusion, and give naloxone for opioid-induced respiratory depression while calling for senior and nursing help. Once the child is safe I would preserve the chart, infusion and pump as evidence, notify the consultant in charge and the safety lead, and begin the structured response — report, root cause analysis, open disclosure and support for the registrar. I can already see two problems here: a medication calculation error, and a failure of escalation, because the rising respiratory rate was documented but not acted on. [12]

Branch A — Framework

Examiner: What model do you use to explain how this happened, and why does it matter? [3]

Candidate: Reason's Swiss cheese model. An accident is a hazard passing through aligned holes across defensive layers — organisation, supervision, preconditions and the individual's acts. The active failure here is the calculation slip at the sharp end; the latent conditions include the handwritten chart with no dose-range checking, the missing independent double-check of a high-alert medicine, and the failure of the escalation pathway. The model matters because it points me to the system approach — rebuild the defences — rather than the person approach of blaming the registrar. [3] [8]

Branch B — Why children?

Examiner: Why is this error more likely in a child than in an adult? [6]

Candidate: Because every paediatric prescription is a weight-based calculation, which multiplies the chance of a tenfold error. Many paediatric medicines are off-label with no standard reference to catch a wrong dose, and a four-year-old's therapeutic margin is narrower than an adult's. Kaushal showed paediatric medication errors and preventable adverse drug events are higher than in adults, and highest in critical care. The structural fixes are computerised order entry with weight-based dose checking, standardised concentrations, and an independent double-check of high-alert medicines. [6] [8]

Branch C — Failure to rescue

Examiner: The respiratory rate was rising for two hours and nobody escalated. Talk me through that. [5]

Candidate: This is failure to rescue — the most lethal and most preventable pattern. The child's physiology wandered for hours before the collapse, the observations were written down, but no trigger fired and no one called for help. The defect is rarely one clinician missing one number; it is a failure of the escalation culture and the pathway. The defences are an early-warning score, a structured escalation tool such as SBAR, a rapid-response system, and — above all — a culture that makes calling for help easy and expected. [5]

Branch D — The response and disclosure

Examiner: How will you speak to the family? [12]

Candidate: Through a timely, honest, apologetic open disclosure — what happened, what is known so far, what is being done, and an expression of regret for the harm. I would provide a senior point of contact, avoid blame and premature speculation, and commit to feeding back the investigation and the changes. Done well, open disclosure supports the family and sustains trust; done poorly or avoided, it deepens the harm. [12]

Branch E — The second victim

Examiner: The registrar is tearful and withdrawn. What is this and what do you do? [4]

Candidate: This is the second victim — a clinician harmed by involvement in an adverse event, at risk of acute distress and of further error. I would provide immediate peer support, relieve them from front-line duties as appropriate, and arrange formal follow-up. In a just culture, an honest error is consoled and the system is fixed; an unsupported second victim is both unkind and unsafe, because a distressed clinician becomes a latent condition for the next event. [4] [3]

Close

Stabilise the child first, preserve the evidence, escalate to the consultant and safety lead, then run the full sequence — report, root cause analysis to the latent conditions, open disclosure, support for the second victim, and implement and measure corrective actions including dose-range checking, an independent double-check of high-alert medicines, and a structured escalation pathway. [3] [12] [13]