Post-Anaesthetic Shivering — FRCA Final MCQ

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ModerateDay SurgeryPost-Anaesthetic ShiveringFRCA Final

A 40-year-old ASA I man develops marked generalised shivering in recovery after day-case knee arthroscopy. His core temperature is 35.2°C and active forced-air warming has been commenced. His medication history is unremarkable. Which intravenous drug is the best-established treatment for rapidly suppressing the shivering while rewarming continues?

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Correct answer: D — Pethidine 25 mg

Pethidine is the best answer. It has a disproportionately strong antishivering effect compared with its analgesic potency and is better established for terminating post-anaesthetic shivering than conventional mu-opioid doses. Its precise mechanism is incompletely defined but includes opioid-mediated lowering of the shivering threshold, with mu- and kappa-receptor activity implicated. Active forced-air warming must continue because suppressing shivering does not correct the underlying core hypothermia. Morphine and fentanyl may reduce shivering but are less reliably effective; paracetamol does not rapidly alter thermoregulatory shivering. Ondansetron has evidence mainly for prophylaxis and is less established for treating active shivering. Pethidine should be given slowly with monitoring for sedation, respiratory depression, nausea and vomiting, and avoided with monoamine oxidase inhibitors.

Reference: Lopez MB. Postanaesthetic shivering - from pathophysiology to prevention. Romanian Journal of Anaesthesia and Intensive Care. 2018;25(1):73-81. https://pubmed.ncbi.nlm.nih.gov/29756066/