Description

Train-of-Four (TOF) stimulation of the peripheral nerve results in muscle twitching that can be used to quantify the degree of neuromuscular blockade in a patient. The test is quick and easy to do using inexpensive equipment. It can help guide administration of blocking agents during anesthesia or in the intensive care unit (ICU).


 

Device: TOF stimulating unit

 

Monitoring:

(1) electromyogram (EMG)

(2) muscle twitches (for example, thumb movements if the radial nerve is stimulated)

Number of Twitches After Stimulation

Amplitude

Corresponding Level of Neuromuscular Blockade

4

all 4 equal

0% (no blockade)

4

declining

< 75%

3

declining

75 – 85%

2

declining

85 – 90%

1

single weak

91 – 99%

0

none

100%

from MKSAP Figure 4 page 68

 


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