Neuromuscular Monitoring, Depth of Anaesthesia Measurement, and Neuro-Electrophysiology — WACS Viva & Clinical Scenarios (Clinical Measurement and Equipment)

Exam-style neuromuscular monitoring, depth of anaesthesia measurement, and neuro-electrophysiology viva scenarios with examiner probes and model answers for…

Scenarios covered

• SCENARIO 1: A 45-year-old female is undergoing a 4-hour laparoscopic hysterectomy. Muscle relaxation is maintained with intermittent rocuronium boluses. At the conclusion of surgery, you place an acceleromyographic (AMG) neuromuscular monitor on the ulnar nerve to stimulate the adductor pollicis. The qualitative peripheral nerve stimulator shows 4 twitches on Train-of-Four (TOF), but the quantitative monitor displays a TOFR of 0.60. Explain the physical mechanics of acceleromyography, the risks of residual neuromuscular blockade at a TOFR of 0.60, and your pharmacological reversal strategy.
• SCENARIO 2: A 35-year-old male with severe traumatic brain injury is undergoing an emergency decompressive craniectomy. An intraparenchymal fiberoptic intracranial pressure (ICP) transducer and a processed EEG (BIS) monitor are placed. Mid-surgery, the ICP increases to 28 mmHg, and the BIS monitor reads 18 with a Burst Suppression Ratio (BSR) of 65%. Detail the physical instrumentation and zeroing of ICP transducers, analyze the electrophysiological significance of the BIS/BSR readouts, and outline your neuro-anaesthetic management.
• SCENARIO 3: A 16-year-old female is undergoing corrective spinal surgery for adolescent idiopathic scoliosis. The neurophysiology team utilizes combined Somatosensory Evoked Potentials (SSEPs) and Transcranial Motor Evoked Potentials (tc-MEPs). Thirty minutes after pedicle screw placement, there is a sudden 60% loss of MEP amplitude in the right lower extremity. Explain the neurophysiological differences between SSEPs and MEPs, the impact of volatile vs. intravenous anaesthetics on these signals, and your emergency response protocol.
• SCENARIO 4: A 52-year-old male with end-stage renal disease receives rocuronium (0.6 mg/kg) for rapid sequence induction during an emergency repair of a strangulated inguinal hernia. After 90 minutes, neuromuscular stimulation of the adductor pollicis reveals a TOF count of 0, but a Post-Tetanic Count (PTC) of 2. Explain the physiological and physical mechanism of post-tetanic potentiation, interpret this level of block, and detail your reversal and airway extubation timeline.
• SCENARIO 5: You are administering Total Intravenous Anaesthesia (TIVA) with propofol and remifentanil to an 82-year-old frail female undergoing a total hip replacement. You apply a frontotemporal Bispectral Index (BIS) sensor. During electrocautery activation, the BIS reading jumps from 42 to 78, accompanied by high-frequency EMG artifacts. Detail the mathematical and algorithmic architecture of BIS (Fast Fourier Transform, bispectral analysis, sub-parameters), explain electrocautery and EMG interference, and formulate your titration plan.