2003A08 Describe the onset and offset of neuromuscular blockade at the diaphragm, larynx and adductor pollicis
 after administration of 2.5xED95 dose of vecuronium. Comment on the differences observed.
What are the clinical implications of these differences?

 

List:

·      Intro

·      Muscle location comparison

·      Implications

 

Intro:

ED95

·   Definition: dose that produces 95% ↓single twitch height in 50% population IN ADDUCTOR POLLICIS

·   2xED95 is classically the intubating dose

·   2.5xED95 Vecuronium = 0.125mg/kg

·   Intubating conditions achieved 2-3 mins

Graph

 

Muscle location comparison:

 

Diaphragm, larynx

Orbicularis oculi, pharynx

Adductor pollicis

Blood flow rate

Higher

Higher

Lower

ACh vesicle release

Higher

Lower

Lower

ACh receptor number

Higher

Lower

Lower

Rate of onset

Faster

Faster

Slower

Max depth

Lesser

Greater

Greater

Rate of recovery

Faster

Faster

Slower

 

Implications: (my thoughts only)

Induction and intubation

·   Orbicularis oculi mirrors larynx -> can intubate earlier

Maintenance

·   Orbicularis oculi mirrors larynx and diaphragm -> ensure adequate paralysis

Reversal and extubation

·   Adductor pollicis lags central muscles -> greater margin of safety at TOF 0.9

 

 

 

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