BIS limitation — FRCA Primary MCQ

Correct answer: A — EMG activity can falsely raise the index

Processed EEG indices may be affected by electromyographic activity and artefact, so the value must be interpreted clinically. Airway laser fire risk is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Residual non-depolarising neuromuscular block is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Non-interchangeable screw thread is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Hydrostatic levelling error is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. In Primary FRCA physics and measurement, the safest answer is the one that follows the underlying physical principle and the limitations of the device.

Reference: Davis and Kenny Basic Physics and Measurement in Anaesthesia; RCoA Primary FRCA syllabus