Neuromuscular Block Management

Question 1

Define complete, deep, moderate, shallow, minimal and recovery in terms of neuromuscular blockade

Answer 1

Complete- Train of four (TOF) count = 0 post-tetanic count (PTC) = 0
Deep- TOF 0 PTC >1
Moderate- TOF 1-3
Shallow- TOF 4 with fade (ratio <0.4)
Minimal- TOF 4 with minimal fade (ratio 0.4-0.9)
Recovery- TOF 4 with ratio >0.9

Question 2

Complications of minimal neuromuscular block in the extubated patient

Answer 2

• Reduced VC
• Reduced grip strength
• Impaired swallowing- aspiration risk
• Upper airway obstruction
• Subjective feeling of weakness
• Reduced chemoreceptor response to hypoxia

Question 3

Qualitative measures of neuromuscular block

Answer 3

• Grip strength
• Able to sustain a head lift
• Qualitative peripheral nerve stimulators

Question 4

Quantitative measures of neuromuscular block

Answer 4

• Acceleromyography: A piezoelectric sensor is placed on the thumb and the nerve is stimulated. The sensor is able to compare the acceleration of the twitches and give a ratio.
• Electromyography: The ulnar nerve is stimulated and an electrode will measure the motor-evoked potential peak amplitude and compare.

Question 5

Sites for monitoring neuromuscular block

Answer 5

• Adductor pollicis- ulnar nerve, gold standard
• Flexor hallucis- post tibial n
• Occularis occuli- facial n, not recommended

Question 6

Neostigmine doses

Answer 6

• If TOF 4 and ratio >0.4 then 30mcg/kg, requires 10 min for peak effect
• If TOF 4 and ratio <0.4 then 50mcg/kg may require 20-30mins for peak effect
• If TOF <4 then wait

Question 7

Suggamadex doses

Answer 7

• Complete block: 16mg/kg
• Deep Block: 4mg/kg
• Moderate and above: 2mg/kg

Question 8

Adverse drug events with suggamadex

Answer 8

• Interaction with progesterone containing contraceptions
• ? high risk of anaphylaxis
• ? bradycardia