Procedural sedation medicines — branching viva

Opening (candidate)

I would treat this as a procedural sedation for a painful reduction, planned against four questions: which agent, what dose, what to do about the recent snack, and how I keep the airway safe. My plan is dissociative ketamine by the intravenous route at roughly 1 to 2 milligrams per kilogram, dosed from his measured weight, with a dedicated sedationist and continuous capnography. The recent snack does not delay an urgent reduction, because the evidence shows fasting does not reduce adverse events in emergency sedation. [1] [4]

Branch A — Why ketamine, and what dose

Examiner: Why ketamine rather than midazolam or propofol for this child, and what dose would you give? [1]

Candidate: Ketamine is a non-competitive NMDA receptor antagonist that gives dissociative sedation with genuine analgesia, which midazolam and propofol do not, because both are GABA-A sedatives with no analgesia and sedating a painful procedure without analgesia is the cardinal sedation error. Ketamine also preserves airway reflexes and cardiovascular tone through sympathetic stimulation, tolerable outside theatre, where propofol has a narrow margin to apnoea and hypotension. For a 16 kg child I would give intravenous ketamine at 1 to 2 milligrams per kilogram, about 16 to 32 milligrams, titrated to the dissociative state, and I would use the intramuscular route at 4 to 5 milligrams per kilogram only if intravenous access proved infeasible. [1] [2]

Branch B — The fasting question

Examiner: He ate 45 minutes ago. Does that change your plan? [4]

Candidate: It informs but does not delay the plan. The traditional elective fasting windows were built for general anaesthesia, and the procedural sedation literature repeatedly shows that fasting duration does not reduce the risk of adverse events in the emergency setting; Bhatt's multicentre cohort in JAMA Pediatrics found no association between fasting and desaturation, vomiting, or aspiration. For an urgent painful fracture reduction I would therefore proceed, document the decision, and manage the small aspiration risk with suction readiness, lateral recovery positioning, and a vigilant team. I would reconsider only if the procedure were elective and safely postponable, in which case I would apply the usual fasting windows. [4]

Branch C — Monitoring and the independent sedationist

Examiner: What monitoring would you set up, and why is capnography not optional? [5]

Candidate: Continuous pulse oximetry, ECG, and intermittent non-invasive blood pressure with alarm limits set, and continuous capnography. Capnography is not optional because it detects hypoventilation within seconds; once supplemental oxygen is running, pulse oximetry can read normal while the child becomes dangerously hypercapnic, so oximetry alone is insufficient for moderate and deep sedation. Equally important is the team: a dedicated, trained sedationist whose sole task is the airway and the monitor, distinct from the proceduralist, who cannot watch the drug and the wound at once, and a checked SOAP-ME setup of suction, oxygen, airway adjuncts, drawn-up reversal agents, and emergency equipment. [5]

Branch D — Laryngospasm

Examiner: He becomes stridulous during reduction. Talk me through your management. [2]

Candidate: That is laryngospasm, and I manage it in a ladder. I stop the procedure and the sedative, call for help, and apply a firm jaw thrust with continuous positive airway pressure and one hundred per cent oxygen, and I suction secretions; many episodes resolve here. If spasm persists I deepen with a propofol bolus or give a small dose of a rapid-acting neuromuscular blocker by skilled hands, with the difficult-airway pathway and a supraglottic device ready, because a child who cannot be ventilated is seconds from harm. I would also reflect on the predictors that should have been screened: young age, an active upper respiratory infection, and airway or head-and-neck procedures, and I would screen the next child more deliberately. [2] [1]

Branch E — Alternatives and recovery

Examiner: When would you choose nitrous oxide or dexmedetomidine instead, and when is this child safe to go home? [3]

Candidate: Nitrous oxide I would choose for a brief, moderately painful procedure such as venepuncture or a minor laceration, where its rapid onset and recovery and preserved airway suit it, and I would avoid it in pneumothorax, bowel obstruction, or vitamin B12 deficiency. Dexmedetomidine I would choose when sparing respiratory drive matters, such as in a neurodevelopmentally complex child or for imaging, accepting its bradycardia and hypotension and a slower recovery. For discharge, I would watch him in a monitored area until his consciousness, airway, breathing, and circulation return to baseline and a validated discharge score is met, typically thirty minutes to an hour after ketamine, and I would safety-net the family on emergence phenomena, oral intake, and the features that should prompt return. [3] [5]

Close

I would document the agent, dose, route, depth achieved, the monitors in use, any adverse event and its management, and the recovery time, and report any significant event for review so the learning returns to protocol and screening. The family receives a clear explanation of the procedure, the expected recovery phenomena, and the safety-net before discharge. [1] [4]