Opioid stewardship and complex analgesia — formative SAQs · Paeds SAQs

Prompt

SAQ 1 tests the weight-based morphine dose and the patient- and nurse-controlled analgesia setup with the sedation-score monitoring, the multimodal opioid-sparing backbone, and the opioid-rotation principle with the incomplete cross-tolerance reduction. SAQ 2 tests the recognition and titrated management of opioid-induced respiratory depression in a postoperative child, including the naloxone dose, the reasoning behind titration, and the plan for recurrence.

SAQ 1 — Postoperative opioid stewardship in a school-age child

Question 1 — 10 formative marks; suggested time 15 minutes [1]

A 7-year-old boy weighing 23 kg is admitted overnight after open appendicectomy for perforated appendicitis. He is in moderate-to-severe pain and is started on a morphine patient-controlled analgesia device by the acute pain team. [1]

State the weight-based intravenous and oral morphine doses, with the maximum and the monitoring. (2 marks)
State the patient-controlled analgesia morphine bolus, lockout and background infusion parameters, and the age and understanding criteria for a PCA. (3 marks)
State the non-opioid multimodal backbone that surrounds the opioid and the stewardship goal it serves. (2 marks)
After 36 hours the team rotates him to oral morphine. State the equianalgesic principle and the incomplete cross-tolerance reduction, and name one agent whose conversion is specialist-only and why. (3 marks) [7] [11]

Full-credit answer — SAQ 1

Reveal full-credit answer for SAQ 1

1. Morphine dose

Morphine is dosed at 0.1 to 0.2 mg per kg intravenously, titrated to the pain score and monitored with a sedation score and a respiratory rate; for this 23 kg child one intravenous bolus is about 2.3 to 4.6 mg. The oral dose is 0.2 to 0.5 mg per kg every four hours, capped at the adult maximum, with a double-check and a leading zero on the prescription. [1]

2. PCA parameters

A PCA morphine device delivers a bolus of 10 to 20 microgram per kg (about 230 to 460 microgram for this child), with a lockout of 5 to 10 minutes that prevents re-dosing within the window, and an optional low background infusion of 0 to 4 microgram per kg per hour. PCA is used for a child who can understand the device and press the button, commonly from about six or seven years; an infant or a child who cannot use a PCA receives nurse-controlled analgesia, and parent-controlled analgesia by proxy is not permitted outside an approved protocol. [1]

3. Multimodal backbone

The non-opioid multimodal backbone is regular paracetamol and an NSAID (where not contraindicated), a regional or local anaesthetic technique, an NMDA antagonist such as ketamine, and an alpha-2 agonist such as dexmedetomidine or clonidine, with a gabapentinoid for neuropathic pain. The stewardship goal is to minimise total opioid exposure, which both improves recovery and reduces opioid-related adverse effects, and it is the single most evidence-based stewardship move. [11]

4. Rotation and cross-tolerance

The equianalgesic principle is that 10 mg of intravenous morphine is approximately equianalgesic to 30 mg of oral morphine. The crucial safety step is that the calculated equianalgesic dose of the new opioid is then reduced by 25 to 50 per cent for incomplete cross-tolerance, because a child tolerant to one opioid is not fully tolerant to another and a straight equianalgesic conversion over-doses them. Methadone is the specialist-only exception: its conversion ratio to morphine is non-linear (it steepens as the prior opioid dose rises) and its long and variable half-life accumulates, so methadone rotation is undertaken only by the specialist pain or palliative team with a written protocol. [7]

SAQ 2 — Opioid-induced respiratory depression on the ward

Question 2 — 10 formative marks; suggested time 15 minutes [8]

A 9-year-old girl on a morphine PCA after orthopaedic surgery is found by the nurse to be hard to rouse, with a respiratory rate of 8 per minute and a sedation score of 3. The pain score is low. The registrar is called. [8]

Give the immediate actions in the first two minutes, in order. (3 marks)
State the naloxone dose, route and dosing strategy, and the specific endpoint you are titrating to. (3 marks)
Explain why naloxone is titrated rather than given as a single wake-up dose. (2 marks)
State the plan for the next two hours, and two non-opioid causes of an altered child you must exclude in parallel. (2 marks) [8] [9]

Full-credit answer — SAQ 2

Reveal full-credit answer for SAQ 2

1. Immediate actions

Assess and support the airway and breathing first: stimulate the child, position the airway, give bag-valve-mask support with oxygen for the slow and shallow breathing, and call for senior and intensive-care help for a child this sedated. Reduce or stop the PCA demand doses, keep the device at the bedside, and take a full set of observations including oxygen saturations, a bedside glucose and a temperature. Only after the airway and breathing are supported is naloxone prepared. [8]

2. Naloxone dose and endpoint

Naloxone is given 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 child who is breathing adequately and is rousable, not a child who is fully awake and in pain. For this 30 kg child a starting increment is about 15 to 60 microgram. Intramuscular naloxone is used only if intravenous access is unavailable. For a true opioid overdose (rather than therapeutic over-sedation) the dose is larger, 0.1 mg per kg intravenously repeated as needed. [9]

3. Why titrate

Naloxone is titrated because the goal is to restore the drive to breathe while leaving the analgesia intact. A large wake-up bolus displaces the opioid all at once, throws the child into acute pain and withdrawal, and — because naloxone's half-life (about 30 to 80 minutes) is shorter than morphine's several hours — wears off before the opioid, so the child is over-sedated again, now in a worse state. The titrated approach gives the smallest dose that restores breathing, preserves analgesia, and pairs the reversal with a plan to reduce the opioid and address the cause. [9]

4. The next two hours and the differential

Monitor the child continuously for recurrence, because the opioid outlasts naloxone; have repeat naloxone boluses or an infusion ready, and review the PCA parameters and the opioid dose with the acute pain team. In parallel, exclude two non-opioid causes of an altered child: hypoxia (check oxygen and consider capnography, because oximetry alone misses early hypercapnia) and hypoglycaemia (a bedside glucose, because hypoglycaemia mimics and compounds opioid sedation and is rapidly reversible). Septic encephalopathy and residual anaesthetic are kept on the differential. [8] [9]

References

[1]Donado C, Solodiuk J, Rangel SJ, et al. Patient- and Nurse-Controlled Analgesia: 22-Year Experience in a Pediatric Hospital Hospital Pediatrics, 2019.PMID 30655310
[7]Quigley C Opioid switching to improve pain relief and drug tolerability Cochrane Database of Systematic Reviews, 2004.PMID 15266542
[8]Bateman JT, Saunders SE, Levitt ES, et al. Understanding and countering opioid-induced respiratory depression British Journal of Pharmacology, 2023.PMID 34089181
[9]Saari TI, Strang J, Dale O, et al. Clinical Pharmacokinetics and Pharmacodynamics of Naloxone Clinical Pharmacokinetics, 2024.PMID 38485851
[10]Hadland SE, Agarwal R, Raman SR, et al. Opioid Prescribing for Acute Pain Management in Children and Adolescents in Outpatient Settings: Clinical Practice Guideline Pediatrics, 2024.PMID 39344439
[11]Chou R, Gordon DB, de Leon-Casasola OA, et al. Management of Postoperative Pain: A Clinical Practice Guideline From the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists' Committee on Regional Anesthesia, Executive Committee, and Administrative Council The Journal of Pain, 2016.PMID 26827847