Post-Tetanic Count Monitoring — FRCA Final MCQ

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ModerateAnaesthetic Equipment & SafetyPost-Tetanic Count MonitoringFRCA Final

A 50-year-old man (ASA II) is undergoing a laparoscopic hernia repair. The surgeon requests that you maintain neuromuscular block at a deep level (PTC 1-2). Which neuromuscular monitoring technique is required to assess deep block?

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Correct answer: C — Post-tetanic count stimulation

When the TOF count is zero (no visible twitches), the depth of block cannot be further differentiated by TOF alone. Post-tetanic count (PTC) is required to assess deep neuromuscular block. PTC involves a 50 Hz tetanic stimulus for 5 seconds, followed 3 seconds later by single twitch stimuli at 1 Hz. The number of visible post-tetanic twitches indicates block depth: PTC 0 = intense block; PTC 1-5 = deep block; PTC >5 = recovery beginning (TOF twitches will reappear shortly). PTC guides timing for sugammadex reversal of deep block.

Reference: RCOA – 2023 – Neuromuscular monitoring; Naguib M – 2018 – Neuromuscular pharmacology