Bier's Block Minimum Tourniquet Time — FRCA Final MCQ

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EasyRegional AnaesthesiaBier's Block Minimum Tourniquet TimeFRCA Final

A 55-year-old man (ASA II) has a wrist fracture reduced in the emergency department under a Bier's block (intravenous regional anaesthesia). The tourniquet has been inflated for 15 minutes. The surgeon has completed the reduction. The tourniquet must remain inflated for a minimum of how long after injection?

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Correct answer: B — 20 minutes

The tourniquet during Bier's block must remain inflated for a MINIMUM of 20 minutes after injection of local anaesthetic, regardless of whether the procedure is complete. This allows sufficient tissue fixation of the local anaesthetic. Deflation before 20 minutes risks rapid systemic absorption of large quantities of LA, potentially causing severe LAST (seizures, cardiovascular collapse). After 20 minutes, the tourniquet should be deflated gradually (cycled deflation: deflate for 10 seconds, reinflate for 1 minute, then fully deflate) to slow the rate of LA release into the systemic circulation.

Reference: RCOA – 2023 – Regional anaesthesia: Bier's block; AAGBI – 2020 – IV regional anaesthesia guidelines