skip to main content

Post-Anaesthetic Shivering Mechanism — FRCA Final MCQ

Instant feedback + full explanation. One question, done properly.

ModerateGeneral AnaesthesiaPost-Anaesthetic Shivering MechanismFRCA Final

A 45-year-old man (ASA I) undergoes appendicectomy under general anaesthesia. In recovery he develops shivering with a core temperature of 35.8°C. What is the mechanism of post-anaesthetic shivering?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: ECombined thermoregulatory and non-thermoregulatory (post-anaesthetic tremor related to volatile agent washout)

Post-anaesthetic shivering has both thermoregulatory and non-thermoregulatory components. Thermoregulatory shivering occurs because general anaesthesia impairs the normal thermoregulatory threshold, causing peripheral vasodilation and heat redistribution from core to periphery. Approximately 40% of post-anaesthetic shivering occurs in normothermic patients, suggesting non-thermoregulatory mechanisms including: uninhibited spinal reflexes during emergence, pain, sympathetic activation, and volatile agent effects on the CNS thermoregulatory centres. This distinction is important because both components respond to pethidine/meperidine (kappa-opioid agonism).

Reference: RCOA – 2023 – Perioperative temperature management; Sessler DI – 2001 – Thermoregulation and anaesthesia