Right dose, right monitoring, right rotation — paediatric opioid stewardship

Candidate brief

You are the paediatric registrar on the ward overnight. A nine-year-old girl, 30 kg, has just returned from theatre after internal fixation of a displaced femoral fracture. She is on a morphine patient-controlled analgesia device set up by the acute pain team, with a background infusion running. The ward nurse asks you to confirm the PCA parameters and the monitoring, and to set the plan for the night. Two hours later the nurse calls you urgently: the child is hard to rouse, with a respiratory rate of 8 per minute and a sedation score of 3. [1]

You have ten minutes to: confirm the PCA parameters and the multimodal opioid-sparing backbone; set the monitoring that gates every dose; respond to the over-sedation event with titrated naloxone and a plan for recurrence; and prepare the next-day rotation to an oral opioid with the cross-tolerance reduction and a safe discharge prescription. [1] [8]

The encounter

1. Confirm the device and the backbone

The candidate confirms a measured weight of 30 kg and a pain score. The PCA morphine device is set to a bolus of 10 to 20 microgram per kg — about 300 to 600 microgram per demand — with a lockout of 5 to 10 minutes and a background infusion of 0 to 4 microgram per kg per hour. She is nine and can use the device; the candidate states that an infant would receive nurse-controlled analgesia and that parent-controlled analgesia by proxy is not permitted outside an approved protocol. The candidate names the multimodal backbone: regular paracetamol and an NSAID where not contraindicated, a regional or local technique for the surgical site, an NMDA antagonist such as ketamine, and an alpha-2 agonist. [1] [11]

2. Set the monitoring that gates every dose

The candidate sets the three-number monitoring: the pain score (numeric scale), a structured sedation score, and the respiratory rate counted over a minute, taken together at each assessment. The candidate states that the next breakthrough dose is gated on the combination — a high pain score with a low sedation score supports the dose, a low pain score with a rising sedation score holds it. The candidate requests capnography for this child on a background infusion, because oximetry alone misses the hypercapnia of early opioid over-sedation, and keeps naloxone at the bedside. [8]

3. Respond to the over-sedation event

The candidate responds in order: assess and support the airway and breathing first, with stimulation, airway positioning and bag-valve-mask support with oxygen for the slow and shallow breathing; call for senior and intensive-care help; reduce the PCA demand doses and keep the device at the bedside; take a full set of observations including oxygen saturations, a bedside glucose and a temperature. Only then is naloxone prepared. The candidate gives naloxone intravenously in increments of 0.5 to 2 microgram per kg, repeated every two to three minutes, titrated to the respiratory rate — the endpoint is a breathing, rousable child, not a fully awake child in pain. [9]

4. Plan the next two hours

The candidate states the plan for recurrence: monitor continuously, because the opioid outlasts naloxone (naloxone half-life about 30 to 80 minutes against morphine's several hours), and keep repeat naloxone boluses or an infusion ready. The candidate reviews the PCA parameters and the opioid dose with the acute pain team, and excludes two non-opioid causes of an altered child in parallel — hypoxia (oxygen and capnography) and hypoglycaemia (the bedside glucose). The reasoning behind titration — preserve analgesia, avoid acute pain and withdrawal, plan for the shorter naloxone half-life — is stated. [8] [9]

5. Plan the rotation and the discharge

The candidate rotates to an oral opioid on day three using the equianalgesic principle — 10 mg intravenous morphine to 30 mg oral morphine — and applies the incomplete cross-tolerance reduction of 25 to 50 per cent to the calculated equianalgesic dose, splitting the reduced total into a regular and a breakthrough dose. The candidate names methadone as non-linear and specialist-only. At discharge the candidate prescribes the smallest effective quantity, writes the dose in milligrams with a leading zero and no trailing zero, provides a dosing schedule and a disposal plan for any leftover opioid, and teaches back to the family. The written safety-net names increasing drowsiness, slow or shallow breathing, unrousability and worsening pain as features that should bring the child back urgently. [7] [10]

Marking domains