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Chapter 25
Neuromuscular Transmission MonitoringMuscle relaxants are employed in anesthesia to provide muscle relaxat ion and/orabol ish pat ient movement . Numerous s tudies have documented enormous var iat ion
in pat ients ' responses to muscle relaxants . Disease s tates and perioperat ive
medicat ions can also modify the responses of these medicat ions ( 1 ) . The depth of
neuromuscular block (NMB) should be monitored when muscle relaxants are used
to avoid drug overdosage or underdosage and residual NMB during recovery
(2 ,3 ,4 , 5 ,6 , 7 ).
EquipmentMonitor ing the magni tude of NMB is acco mplished by del iver ing an electr ical
s t imulus near a per ipheral motor nerve and evaluat ing the evoked response of the
muscle(s) innervated by that nerve.
S t i m u l a t o r
Several s t imulators are shown in Figure 25.1 . Desirable features include
compactness, l ight weight , and
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simplici ty. Most are bat tery-operated with a means to check the bat tery s tatus.
Mounting brackets for securing the device are desirable. A st imulator may be in a
module in a mult iparameter monitor. The abi l i ty to del iver information to an
automated record ( Chapter 28 ) should be considered when choosing a s t imulator.
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View Figure
Figure 25.1 Neuromuscular stimulators. A: This simpledevice has only two patterns of stimulation: tetanus andsingle twitch. The delivered current cannot be varied and isnot displayed. Note the metal ball electrodes. (Courtesy ofProfessional Instruments, a subsidiary of Life Tech, Inc.) B: This unit has three modes of stimulation: single stimulus(twitch), tetanus, and TOF. The current is varied by using arheostat at the side, but there is no display of the current
being delivered. C: This unit has four patterns ofstimulation: single twitch (available at 0.1 and 1 Hz), TOF(which can be repeated automatically every 12 seconds),50-Hz tetanus, and DBS. It also is capable of delivering thestimulus pattern for obtaining a PTC. The selected current isdisplayed in the window. Failure to deliver this current willcause a mark to be displayed to the right of the word ERROR . Note that the connections for the lead wires are ofdifferent colors. D: This unit has three modes ofstimulation: single stimulus (which can be delivered at 0.1,1, or 2 Hz), tetanus (which is available at a frequency of 50to 100 Hz), and TOF. Stimulus current is varied by using arheostat at the side. The delivered current is displayed in awindow, to the left of which is an indicator that lights whena stimulus is being delivered. A battery status check buttonis present.
CurrentCurrent , not vol tage, is the determining factor in nerve s t imulat ion. Because skin
resis tance may change, only a s t imulator that automatical ly adjusts i ts output to
maintain a constant direct c urrent can ensure unchanging st imulat ion with changes
in skin resis tance. Wiping the
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skin with alcohol wil l remove insulat ing skin oi ls and lower the resis tance.
The force of muscle c ontract ion is proportional to the number of act ivated muscle
f ibers . I f a motor nerve is s t imulated with suff icient current , a l l of the muscle f ibers
suppl ied by that nerve wil l contract . The current required for this is cal led the
maximal current . In the cl inical set t ing, s t imuli of g reater than maximal
(supramaximal) intensi ty are used to ensure that maximal s t imulat ion is del ivered i f
resis tance increases. In the majori ty of pat ients , a current of 30 mil l iamperes (mA)
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will produce a supramaximal response when the ulnar nerve is stimulated ( 8 ) . When
the poster ior t ibial nerve is s t imulated, higher currents are needed ( 9 ). A
supramaximal current is general ly 2.5 to 3 t imes higher than the lowest currentcapable of el ici t ing an evoked response ( threshold current) ( 10 ) . Higher currents
may be needed in pat ients with edema ( 11 ,12 ) or diabetes ( 13 ). Much lower
currents (5 to 8 mA) are needed when needle electrodes are used ( 14 ).
A curre nt display is us ef ul in al er ti ng th e user to th e pos sibi l i ty of a di sconne c ti on ,
broken lead, weak bat tery, or poorly conduct ing electrodes, because these
problems wil l cause the current to be reduced. Some st imulators have an alarm to
warn when the selected current is not being delivered.
A subma ximal cu rr ent ma y be bett er f or awa ke pa t ien ts o r for thos e re cov e ri ng f ro m
anesthesia, because patient discomfort increases with the intensity of the
st imulat ing current ( 15 ,16 , 17 , 18 ). Use of a submaximal current may result in more
rel iable detect ion of residual NMB when visual or t act i le monitoring is used ( 19 ). A
submaximal current is not rel iable for general NMB monitor ing.
FrequencyThe frequency of s t imuli is usual ly expressed in Hertz (Hz) , which is cycles/second.
One Hz is one cycle/ second, and 0.1 Hz is equal to 1 s t imulus every 10 seconds.
With a nondepolar izing block, increased st imulus frequency wil l s horten the onset
t ime and prolong the durat ion of act ion ( 20 ,21 ).
WaveformThe stimulus waveform should be rectangular (square wave) and monophasic.
Biphasic waves may produce repet i t ive s t imulat ion, which can lead to
underestimation of the depth of NMB present.
DurationThe durat ion should be 300 s or less ( 20 ) . I f the durat ion of the pulse is over 0 .5
msec, a second action potential may be triggered.Stimulation Patterns
S i n g l e Tw i t c h
Single- twitch (T 1 ) s t imuli are usual ly del ivered at a f requency of 0.1 or 1 Hz. A
frequency greater than every 10 seconds is associated with a progressively
diminished response and could resul t in overest imat ing the NMB.
The control response s t rength is noted ( Fig. 25.2A ). The s t rengths of subsequent
twitches are then compared with the control and expressed as a percentage of the
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control (s ingle-pulse or - twitch depression, T 1 %, T1%, T 1 :T c ) . With both a
nondepolar izing and a depolar izing block, there wil l be progressive depression of
the response as the block develops. A decrease in temperature wil l a lso cause areduced response ( 22 ,23 ,24 ,25 ,26 ).
The single s t imulus is useful in establ ishing a supramaximal s t imulus and for
ident i fying when condi t ions sat isfactory for intubat ion have been achieved. I t can
be used ( in conjunct ion with a tetanic s t imulus) to monitor deep levels of NMB (the
post- tetanic count , discussed below).
There are several disadvantages associated with using single twitch. There needs
to be a control . I t cannot dis t inguish between a depolar izing and nondepolar izing
block. Most important ly, the response 's return to control level does no t guarantee
that ful l recovery from NMB has occurred.
T r a i n - o f - f o u r
Train-of-four (TOF, T 4 , T 4 /T 1 ) consists of four s ingle pulses of equal intensi ty
del ivered at intervals of 0.5 seconds (2 Hz) ( Fig. 25.2B ) ( 27 ) . TOF should not be
repeated more frequent ly than every 10 to 12 seconds ( 4 ). Many modern
st imulators do not al low the T OF to be repeated more of ten. Use of TOF ev ery 10
seconds wil l resul t in a shorter onset t ime for NMB than i f i t i s used every 20
seconds ( 21 ,28 ).
With the control response (before any relaxant has been given) , a l l four responses
are the same. The pat tern seen with a depolar izing block differs f rom that of a
nondepolar izing block ( Fig. 25.2B ). With a par t ial depolar izing block, there is an
equal depression of al l four twitches. With a nondepolarizing block, there is
progressive depression of height with each twitch (fade) . As the block is deepened,
the fourth twitch wil l be el iminated f i rs t , then the third, and so on ( Fig. 25.3 ).
Counting the number of twitches (train-of-four-count or TOFC) permits quantitative
assessment of a nondepolar izing block. Wi th recovery or reversal of a
nondepolar izing block, the TOFC increases unt i l there are four responses, thenfade decreases.
The t rain-of-four rat io (T r , T 4 rat io, T 4 :T 1 , T r %, TR%, TOF rat io, TOFR) is the rat io
of the ampli tude of the fourth response to that of the f i rs t , expressed as a
percentage or a fraction. It provides an estimation of the degree of nondepolarizing
NMB. In the absence of nondepolar izing block, the TOFR is approximately 1
(100%). The deeper the block, the lower the TOFR ( Fig. 25.3 ) . Since determining
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the TOFR requires that four twitches be present , i t c annot be used to monitor a
deep block.
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View Figure
Figure 25.2 Patterns of stimulation and response. A: Single-stimulus stimulation at 1 Hz (1 stimulus/second).The height of the control twitches are noted. With either adepolarizing or a nondepolarizing block, twitch height isdecreased. B: Train-of-four stimulation. Four successivesingle stimuli are delivered with 0.5-second intervals. With
a nondepolarizing block, there will be progressivedepression of the response with each stimulus (fade). With adepolarizing block, the responses will be depressed equally.C, D: Double-burst stimulation. Three stimuli are deliveredat 50 Hz, followed 0.75 seconds later by two or threesimilar stimuli. There will be depression of the response tothe second burst with a nondepolarizing block. Note theincreased height of the response to the first burst comparedwith that seen with TOF stimulation. TW, time weight TOF,train of four; DBS, double-burst stimulation.
View Figure
Figure 25.3 Onset and progressive deepening ofnondepolarizing block using train-of-four stimulation.When there is no NMB present, all four responses are equal.With onset of the block, there is progressive depression oftwitch height with each twitch (fade). As the block
progresses, the last twitch is lost and the TOFC is less than4. TOFR, train-of-four ratio; TOFC, train-of-four count.
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Accurate as ses sme nt of th e TOFR ma y not requ i re a supra ma xima l s t imul us ( 15 ).
Test ing at 10 mA above the lowest current at which four responses can be el ici ted
may provide values that are consistent with those of s upramaximal test ing ( 29 ).The TOF pat tern has several advantages. I t i s a more sensi t ive indicator of residual
NMB than the s ingle twitch. A control is not necessary. I t can dis t inguish between a
depolar izing and a nondepolar izing block and is of v alue in detect ing and fol lowing
the development of a phase II block fol lowing succinylchol ine administ rat ion.
The main disadvantage of TOF is i ts poor performance at both ex tremes of NMB,
deep relaxat ion or near complete recovery ( 4 , 30 ,31 ,32 , 33 , 34 , 35 ) . Tact i le or visual
observat ion of the TOFR is of l i t t le value above a rat io of 0.40.5.
Te t a n u sTetanus is a rapidly repeated (e.g. , 50, 100 or even 200 Hz) stimulus. In the
absence of NMB, this c auses sustained contract ion of the s t imulated muscles . With
a depolar izing block, the response wil l be depressed in ampli tude but sus tained.
With a nondepolar izing block, the response is depressed in ampli tude and the
contract ion is not sustained (fade or decrement) . With profound NMB, there is no
response. Fade af ter 50 Hz tetanic s t imulat ion is a more sensi t ive index of NMB
than single twitch but not suff icient ly sensi t ive to be used for assessing adequate
recovery ( 36 ) . Studies differ on the s ignif icance of fade af ter 100 Hz ( 36 ,37 ) .
The most commonly used frequency is 50 Hz, because i t s t resses the
neuromuscular junct ion to the same extent as a maximal voluntary effor t . Fade may
not be seen a t lower frequencies when a s ignif icant nondepolar izing block is
present . Use of 100 Hz a l lows more s ensi t ivi ty in evaluat ing residual paralysis ( 37 )
and is more useful in monitor ing profound NMB ( 38 ) .
The durat ion of the tetanic s t imulus is important because i t affects fade. The
standard durat ion is 5 seconds. Tetanic s t imulat ion should not be repeated more
often than every 2 minutes ( 39 ,40 ). Some newer stimulators l imit how frequently it
can be used.Post- tetanic faci l i ta t ion (potent iat ion, PTF) is a temporary increase in response to
st imulat ion fol lowing a tetanic s t imulus. I t i s seen with a nondepolar izing, but not a
depolar izing, block ( 39 ,41 ) . I t i s maximal at around 3 seconds and lasts up to 2
minutes.
When the NMB is so profound that there is no response to s ingle twitch or TOF
st imulat ion, i t may be possible to est imate NMB by using the post- tetanic count
(PTC) ( 42 ) . This is performed by administer ing a tetanic s t imulus of 50 Hz for 5
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seconds. After a 3-second pause, s ingle- twitch s t imuli are appl ied at 1 Hz, and the
number of (post- tetanic) responses is counted. The number of twitches el ici ted
increases as the depth of NMB decreases. The t ime to appearance of the f i rs ttwitch in a TOF is inversely related to the number of post- tetanic twitches present
(43 ,44 ,45 , 46 , 47 ,48 ,49 ) . An ev en deeper block can be monitored by count ing the
number of responses fol lowing 100-Hz tetanus ( 38 ).
A s ign if icant di sadvan tage of te tan ic s t imul a ti on is tha t i t i s ver y painf ul and sho uld
be avoided in the conscious pat ient .
D o u b l e - b u r s t S t i m u l a t i o n
Double-burst s t imulat ion (DBS, mini tetanus) consists of two short sequences of 50
Hz tetanic stimuli separated by 750 msec. The two most commonly used are DBS 3 , 3 and DBS 3 , 2 . DBS 3 , 3 consis ts of three 0.2-msec impulses at 50 Hz, fol lowed 750
msec later by an ident ical burst ( Fig. 25.2C ). DBS 3 ,2 consis ts of three impulses
followed by two such impulses 750 msec later ( Fig. 25.2D ). Another permutation of
DBS is DBS 3 , 3 80-40, which is three s t imuli at 80 Hz fol lowed 750 msec later by
three s t imuli at 40 Hz. A modif ied DBS consist ing of f i rs t two st imuli of 0.3 ms
durat ion at 50 Hz and then two st imuli of 0.2 ms durat ion at 50 Hz has also been
used ( 50 ).
The pr imary use of DBS has been to detect residual NMB. Studies show that fade
(response to the second burst weaker than that to the f i rs t ) is more readi ly detected
with DBS than TOF using visual or tact i le monitor ing ( 19 ,30 , 31 , 32 , 33 , 51 ,52 ) . I t a lso
has been used for int raoperat ive assessment of NMB ( 53 ) . DBS and TOF have a
close relat ionship over a wide range of NMB ( 4 , 54 ,55 ) . Another use of DBS is to
assess deep block, s ince the f i rs t twi tch in double burst can be detected at deeper
block levels than the f i rs t twi tch in TOF ( 53 ,56 ,57 , 58 ) .
DBS causes more discomfort to the awake pat ient than TOF st imulat ion but less
than tetanic s t imulat ion ( 16 ) . I t can be used at submaximal currents . This causes
less discomfort in the a wake pat ient and, in most cases, is more rel iable thantest ing with supramaximal s t imuli ( 10 ).
DBS should not be repeated at intervals of less than 12 seconds ( 32 ) . Caut ion
should be used when switching between double-burst and TOF stimulation ( 59 ) . Up
to 92 seconds may be required before the responses are stabilized.
E l e c t r o d e s
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Stimulat ion is achieved by placing two electrodes along a nerve and passing a
current through them. St imulat ion can be carr ied out ei ther t ranscutaneously using
surface electrodes or percutaneously with needle electrodes.
Types
S u r f a c e E l e c t r o d e s
Surface (gel , patch, pad) electrodes have adhesive surrounding a gel led foam pad
in contact with a metal disc with a knob for at tachment to the electr ical lead. They
are readi ly avai lable, easi ly appl ied,
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disposable, self-adhering, and comfortable. The electrodes can be those usually
used to monitor the electrocardiographic tracing. The electrode-skin resistance
decreases with a large conduct ing area, as do sk in burns and pain. However, a
large conduct ing area may make i t di ff icul t to obtain supramaximal s t imulat ion and
may st imulate mult iple nerves, so i t may be bet ter to use pediatr ic electrodes. The
best resul ts are obtained i f the skin is properly c leansed and rubbed with a n
abrasive ( 20 ).
There are electrodes special ly designed for per ipheral nerve s t imulat ion. These
have a d ifferent thickness than electrocardiogram (ECG) electrodes and chemicalbuffers to maintain skin surface pH.
M e t a l E l e c t r o d e s
Some st imulators are suppl ied with two metal bal ls or plates s paced about 1 inch
apart, which attach directly to the stimulator ( Fig. 25.1A ). These are convenient to
use but may not make good contact. Burns have been reported with their use ( 60 ).
N e e d l e E l e c t r o d e s
Needle electrodes may be useful when supramaximal s t imulat ion cannot be
achieved by using surface electrodes. This usual ly occurs when the skin is
thickened, cold, or edematous and in obese, hypothyroid, diabet ic , or renal fai lure
pat ients ( 20 ,61 ).
Addi t io na l com pl ic at io ns (b rok en nee dles , in fec ti on , burn s , and ne rv e da ma ge) are
associated with their use. Needle electrodes carry a greater r isk of direct muscle
st imulat ion than surface electrodes ( 62 ).
Polarity
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View Figure
Figure 25.4 For tactile evaluation of thumb adduction, thehand is supine and a slight preload is applied. (Picturecourtesy of Biometer.)
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M e c h a n o m y o g r a p h y
The mechanomyogram (MMG) ut i l izes a force-displacement t ransducer, such as a
st rain gauge, at tached to a f inger or o ther par t of the body that can be rest rained
by a preload and wil l move when st imulated. The t ransducer converts the
contract i le force into an electr ical s ignal , which is amplif ied and displayed on a
monitor screen or recorded on a chart . Single- twitch h eight , response to tetanic
st imulat ion, and the T 4 ratio can be accurately measured by using an MMG ( 75 ) .
Using the MMG entai ls a n umber of diff icul t ies . These devices are cumbersome and
diff icul t to set up for s table and accurate measurements ( 76 ) . Proper t ransducer
orientat ion, isometr ic condi t ions, and appl icat ion of a s table preload are required
(77 ). Maintenance of muscle temperature within limits is important for accurateresul ts . Mechanomyography is rarely used cl inical ly but is regarded as the gold
standard for scient i f ic measurement of neuromuscular response ( 5 , 78 ) .
A c c e l e r o m y o g r a p h y
With acceleromyography (ACG, AMG), a thin piezoelectric transducer or a small
aluminum rod with electrodes on both s ides is f ixed to the moving part ( 79 , 80 ) ( Fig.
25.5 ). When the part moves, a voltage which is proportional to the acceleration of
the moving part is generated. This me thod requires unrestr icted movement of the
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muscle being st imulated. An elast ic preload can be appl ied to return the moving
part to i ts or iginal posi t ion.
ACG can be us ed to as ses s NMB at th e hand wi th the pati en t' s arm tuc ked a t th eside as long as the thumb can move freely. A protect ive device can be used to
allow thumb motion while protecting the hand and forearm ( 81 ).
Most s tudies show a fai r ly c lose relat ionship between TOFRs measured by ACG
and the MMG ( 29 ,80 , 82 , 83 ,84 ,85 ,86 ,87 ,88 ,89 ,90 , 91 ) or electromyography (EMG)
(75 ,85 ,92 , 93 ), although the results are not interchangeable. Some studies show
poor correlat ion ( 94 , 95 ). In awake patients, the results are affected by extra
movements to which the thumb may be subjected, leading to poor repeatabili ty ( 96 ).
Accelero metry is eas y and con venien t to us e, relat iv e inexpe ns ive, and can be
interfaced with a computer. I t does not require a preload. I t gives more accurate
resul ts than visual or tact i le evaluat ion ( 68 ,92 ).
K i n e m y o g r a p h y
Kinemyography (KMG) ut i l izes a bending sensor that is placed between the thumb
and foref inger ( Fig. 25.6 ) . The core of the sensor is a piezoelectr ic mater ial ( 97 ).
Movement is determined by the change in shape of the mater ial when i t i s bent by
adductor pol l icis muscle contract ion. When the piezoelectr ic mater ial changes
shape, the electr ical charge in the mater ial is redist r ibuted, and this leads to an
electron f low to balance the charges. This f low is measured as a potent ial change
that is proportional to the amount of dis tor t ion. The hand need not be immobil ized
since the position and direction of the thumb do not affect the measurement as long
as the thumb is able to move freely. This device is in a module that can be
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added to a multipurpose monitor ( Fig. 25.7 ). The results of the neuromuscular
test ing are displayed on the monitor screen. This technology can measure TOF,
double burst , and single twitch.
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View Figure
Figure 25.5 Accelerography. The piezoelectric wafer isattached to the moving part-in this case, the thumb. Whenthe thumb moves, an electrical signal proportional to theacceleration is produced. The monitor allows determinationof single-twitch depression, TOF count or ratio and/or thePTC. Responses can be displayed by using the printer.(Courtesy of Biometer International A/S.)
View Figure
Figure 25.6 Sensor for kinemyography. The sensor issecured with tape.
KMG has been compared with mechanomyography ( 98 ,99 ) . There was a greement
as to the time to intubation and recovery, but KMG lagged behind the MMG in
determining recovery from NMB.
P i ez o e l ec t r i c F i lm
This method uses a disposable piezoelectr ic f i lm ( 10 0 ) . This is placed so that i t
spans a movable joint ( 10 1 ) . Muscle movement f rom evoked st imulat ion bends the
f i lm and generates a vol tage that is proport ional to the amount of bending. I t has
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record. Most have alarms for funct ioning errors , loose connect ions, increased skin
resis tance, absence of supramaximal s t imulat ion, and the l ike. Most show the EMG
waveform and automatical ly adjust the gain so that i t occupies the ful l s cale.
View Figure
Figure 25.7 The TOF count and ratio are shown on themonitor. The scale at the bottom shows the frequency ofstimulation (every 20 seconds) and how much time haselapsed since the last stimulus. This information comesfrom a Kinemyograph.
View Figure
Figure 25.8 Electromyography monitor. The T 1%, TOFR,and TOFC can be measured and are displayed in the boxes
to the right of the printer. Responses can be recorded byusing the printer. A T 1% high alarm is present. TOFstimulation is performed automatically every 20 seconds.(Courtesy of Datex Medical Instrumentation, Inc.)
With a nondepolarizing NMB, the action potential amplitude is decreased, and there
is fade with TOF. Frequently, the ampli tude does not return to 100% of control with
recovery, al though the TOFR wil l equal approximately 100%. Different hand
posi t ions may affect the resul ts ( 11 2 ) .
A num ber of s tu dies comp aring EMG an d MMG hav e bee n pu b lishe d
(86 ,113 , 114 ,115 ,116 ,117 ,118 ,119 ,120 ,121 ,122 ,123 , 124 ) . With a nondepolar izing
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superci l i i muscle can be monitored by placing the microphone above the medial
portion of the eyebrow ( 142 , 14 3 , 14 4 ,14 5 ) . The muscles of the larynx can be
monitored by placing the sensor in the vest ibular fold just la teral to the vocal cords(110 , 14 6 ,147 ).
Studies comparing phonomyography, ACG, and mechanomyography by using hand
and corrugator superci l i i muscles show some agreement , a l though the resul ts are
not interchangeable ( 99 , 14 0 ,14 1 ,14 3 ,14 4 ,145 ,146 ).
The phonomyogram is easy to use and can be used on a number of different
muscles . I t provides a s table basel ine with relat ively few dis turbances from ar t i facts
(145 ) . Data c an be t ransferred to an automated anesthesia record.
Since this method monitors lo w frequency sounds, ar t i facts are possible. Vessel
pulsat ions can cause small waves in the basel ine. Electrosurgery uni ts may cause
interference. The mic rophone may come off the ski n.
Choice of Monitoring SiteThe si te of s t imulat ion should be away from the surgical f ield. I f visual or tact i le
monitor ing is to be used, the locat ion must be accessible to the anesthesia
provider. I f a muscle in an arm or l eg is used, the blood pressure should be
measured on a different extremity. An ar ter iovenous shunt does not contraindicate
that arm being used to monitor NMB ( 14 8 ) . I f the pat ient has an upper-motor-
neuron lesion, a nerve in an affected (paret ic) extremity should not be used,
because i t may falsely show resis tance to nondepolar izing drugs ( 14 9 ,15 0 ) . I f
possible, the nerve s t imulator electrodes should be placed on a d ifferent extremity
from the pulse oximeter probe to avoid ar t i facts ( 15 1 ,152 ,153 ).
U l n a r N e r v e
The ulnar nerve is most commonly used, and the adductor pollicis (thumb) muscle
is most commonly monitored. Because this muscle is on the s ide of the arm
opposi te the s i te of s t imulat ion, there is l i t t le direct muscle s t imulat ion. However,residual NMB may be easier to detect tact i lely by using the index f inger ( 71 ) .
The ulnar nerve can be s t imulated at the elbow, wrist , or hand ( Figs. 25.9 , 25.10 ) .
St imulat ion at the wrist wi l l produce thumb adduct ion and f inger f lexion. St imulat ion
at the elbow produces hand adduction as well . If an MMG or electromyogram is
used for measuring the response, the s t imulat ing electrodes should be placed at
the wrist to l imit hand motion.
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View Figure
Figure 25.9 Placement of electrodes for ulnar nervestimulation. A: The electrodes are placed along the ulnaraspect of the distal forearm. B: The electrodes are placedover the sulcus of the medial epicondyle of the humerus.
At the wr is t , the two elec trode s s ho uld be plac ed a lo ng the me d ia l aspec t of th e
distal forearm, approximately 2 cm prox imal to the proximal wris t skin crease with
the negat ive electrode dis tal ( 18 ) ( Fig. 25.9A ). There, the ulnar nerve is superf icial .
Al te rn a te l y, the po si ti ve el ec tro de may be pl ac ed on the dors a l s ide of th e wr i s t
(Fig. 25.10 ) . At the elbow, the electrodes should be placed over the sulcus of the
medial epicondyle of the humerus ( Fig. 25.9B ). Caution must be exercised to
ensure that the electrodes do not cause ulnar nerve compression ( 15 4 ). The
electrodes may also be placed on the hand with the negative electrode on the palm
between the base of the thumb and the second finger and the positive electrode in
the same posi t ion on the dorsal s ide of the hand ( 15 5 ).
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View Figure
Figure 25.10 Alternate placement of electrodes for ulnarnerve stimulation. The negative electrode is placed alongthe ulnar aspect of the ventral side of the wrist. The positiveelectrode is placed on the dorsal side.
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View Figure
Figure 25.11 Sites for electrodes for electromyographymonitoring with ulnar nerve stimulation and recording fromthe dorsal interosseous muscle. The active receivingelectrode is placed in the web between the index finger andthe thumb and the reference electrode, at the base of thesecond finger. Ref, reference electrode; AR, activereceiving electrode; G, grounding electrode; N, negative-stimulating electrode; P, positive-stimulating electrode.
When EMG monitor ing is used, the recording electrodes can be placed over the
hypothenar, thenar, or dorsal interosseous muscle. The electr ical resis tance of the
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palm skin may v ary because of sweat product ion and may be increased in manual
workers ( 156 ) . The dorsum of the hand is less affected than the palm in both
respects , so the dorsal interosseous muscle may be preferred. To record thereact ion of the dorsal interosseous muscle, the act ive receiving electrode is placed
in the web between the index finger and the thumb and the other electrode at the
base of the second finger ( Fig. 25.11 ) . Surface electrodes are s imple to f ix here,
easy to maintain in position, and seldom are disturbed by hand movements ( 15 7 ).
For the hypothenar EMG, both electrodes are placed on the palmar side over the
hypothenar eminence or the act ive electrode is placed on the hypothenar eminence
and the other below the second l ine on the r ing f inger or at the base of the dorsum
of the f i f th f inger ( Fig. 25.12 ) ( 15 8 ,159 ). If the thenar muscle EMG is recorded,
electrodes are placed on the thenar eminence and the proximal phalanx of the
middle or index f inger or the lateral s ide of the base of the thumb ( Fig. 25.13 ) .
Abduct io n of th e thu mb wi th a cons ta nt p re tensio n wi l l br in g th e mu scl es closer to
the skin and minimize movement ( 14 ,109 ).
View Figure
Figure 25.12 Placement of electrodes for electromyographymonitoring from the hypothenar eminence. The activeelectrode is placed over the hypothenar eminence. Thereference electrode may be placed more distally on thehypothenar eminence, below the second line on the ringfinger or at the base of the fifth finger as shown. Ref,reference electrode; AR, active receiving electrode; G,grounding electrode; N, negative-stimulating electrode; P,
positive-stimulating electrode.
For tact i le assessment , the thumb should be held in s l ight abduct ion and the
observer 's f ingert ips placed over the dis tal phalanx in the direct ion of movement
(160 ) ( Fig. 25.4 ) . Preloading the thumb with a rubber band may i mprove visual
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the lateral head of the gastrocnemius muscle ( 166 ) . The use of this muscle may
cause significant leg movement, which may distract the surgeon ( 78 ) .
P o s t e r i o r T i b i a l N er v eTo stimulate the posterior t ibial nerve, electrodes are placed behind the medial
maleolus and anter ior to the Achi l les tendon at the ankle ( Fig. 25.14 ). Stimulation
causes plantar f lexion of the foot and big toe. ACG can be used at this s i te
(9 ,167 ,168 , 16 9 ) . I f EMG monitor ing is used, the receiving electrodes are placed on
the f lexor hal lucis brevis on the plantar surface of the foot or on the intermetatarsal
muscles with the reference electrode on the big toe ( Fig. 25.15 ) .
The poster ior t ibial nerve s i te offers many advantages. I t i s especial ly useful in
chi ldren, when i t i s di ff icul t to f ind room on the arm because of other monitors orinvasive l ines, and when the hand is inaccessible or for o ther reasons such as
amputation, burns, infection, or head and neck procedures ( 170 ).
View Figure
Figure 25.14 Placement of electrodes for stimulating the posterior tibial nerve. The negative electrode is placed behind the medial malleolus, anterior to the Achilles tendon.The positive electrode is placed just proximal to thenegative electrode. Stimulation causes plantar flexion of thegreat toe.
Compared with the ulnar nerve, the poster ior t ibial nerve displays a lag t ime with aslower onset of relaxat ion ( 16 9 ,171 , 17 2 ) . Most s tudies show l i t t le difference in the
time to recovery from the neuromuscular relaxation ( 170 , 17 1 ,17 2 ,173 , 174 , 17 5 ). The
probabi l i ty of tact i le detect ion of fade in response to TOF or DBS is less at the
great toe than at the thumb ( 73 ).
P e r o n e a l N e r v e
To st imulate the peroneal ( lateral popl i teal) nerve, electrodes are placed on the
lateral aspect of the knee ( Fig. 25.16 ) . I t may be necessary to t ry different posi t ions
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to achieve the best response ( 17 6 ,17 7 ) . St imulat ion causes dorsi f lexion of the foot .
Compared with the ulnar nerve, the peroneal nerve shows a s lower onset of
relaxat ion and the muscles show greater resis tance to NMB ( 177 ) .
View Figure
Figure 25.15 Electromyography monitoring using the posterior tibial nerve. The active receiving electrode is placed over the flexor hallucis brevis and the referenceelectrode, on the big toe. Ref, reference electrode; AR,active receiving electrode; G, grounding electrode; N,negative-stimulating electrode; P, positive-stimulatingelectrode.
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View Figure
Figure 25.16 Electrode placement for stimulating the peroneal (lateral popliteal) nerve. The electrodes are placed lateral to the neck of thefibula. Stimulation causes dorsiflexion of the foot.
M u s c u l ar B r a n c h o f t h e F em o r a l Ne r v eThe muscular branch of the femoral nerve can be stimulated and movement in the
vastus medial is muscle evaluated. This muscle can be used to monitor
neuromuscular funct ion in the prone pat ient . When compared with the adductor
pol l icis muscle, the onset of NMB and recovery were qu icker ( 17 8 ) .
F a c i a l N er v e
The facial nerve, which enervates the muscles around the eye, is one of the easier
muscles to s t imulate and observe. I t i s most useful for detect ing the onset of
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should not be used to assess recovery from NMB because the responses may show
complete recovery while s ignif icant NMB is s t i l l present ( 18 2 ,18 3 , 184 , 18 7 ,188 ,189 ) .
M a n d i b u l a r N er v eThe mandibular nerve, a branch of the trigeminal, supplies the masseter muscle. It
can be s t imulated by placing the negat ive electrode anter ior and infer ior to the
zygomatic arch and by placing the posi t ive electrode on the forehead. St imulat ion
causes the jaw to close. The onset of NMB in this muscle is faster than in the hand
muscles ( 19 0 ,191 ) . In adul ts , this muscle is more sensi t ive to both depolar izing and
nondepolarizing drugs than the hand muscles ( 19 0 ,192 ) . In chi ldren, the sensi t ivi ty
may be equal ( 19 1 ).
S p i n a l A c c e s s o r y N er v eThe spinal accessory nerve can be s t imulated by p lacing the electrodes over the
depression between the ramus of the mandible and the mastoid process/
s ternocleidomastoid muscle ( 19 3 ). Stimulation causes the sternomastoid and
trapezius muscles to contract .
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This can cause shoulder and thorax movement with transmission to the abdomen
(194 ) .
R e c u r r e n t L a r y n g e al N er v e
The recurrent laryngeal nerve innervates most of the intr insic muscles of the larynx
(110 ) . I t c an be s t imulated percutaneously by using two electrodes between the
notch between the thyroid and the cr icoid car t i lages ( 11 0 , 195 ). The response can
be measured by placing the t racheal tube cuff between the vocal cords and
measuring pressure changes within the cuff ( 195 ) or by using phonomyography with
the microphone placed in the vest ibular fold lateral to the vocal cords ( 14 6 ). EMG
in the larynx can be accomplished by using a special ized t racheal tube with
incorporated wire electrodes ( 196 ) or an electrode attached to the tube and placed
between the vocal cords ( 13 0 ).
Use
B e f o r e In d u c t i o n
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Prior to anesthesia induction, the stimulator should be connected to electrodes that
are posi t ioned over the selected nerve. I f EMG monitor ing is to be used, the
receiving electrodes should be placed at least 15 minutes before induct ion.Electrode s i tes should be dry and free of excessive hair or scar t issue or other
lesions. The skin should be thoroughly cleansed by using a so lvent such as alcohol ,
then completely dr ied and rubbed br iskly with a gauze pad u nt i l a s l ight redness is
vis ible .
The electrodes should be checked to ver i fy that the gel is moist . I t i s important to
avoid spreading the gel or ov erlapping adhesive while placing the electrodes. A gel
br idge between the electrodes can short-ci rcui t them and lead to poor s t imulat ion.
Af ter th e lea ds a re at tache d to th e e le c tr od e , a pie ce of ta pe shoul d be pl aced ov er
the leads to p revent movement . I t i s good pract ice to create a loop to prevent
electrode displacement ( Fig. 25.18 ).
I n d u c t i o n
During induct ion, the neuromuscular s t imulator can be used to determine the onset
time of NMB, detect unusual sensitivity to relaxants, and determine whether or not
the pat ient is suff icient ly relaxed for t racheal intubat ion.
Af ter in duc ti on of an es the si a bu t bef ore ad mi nis te r ing any mu sc le re la xan ts , the
st imulator should be turned ON and set to del iver s ingle- twitch s t imuli a t 0.1 Hz.
Applyin g s ti mu lati on mo re freq uentl y wi ll ma ke i t ap pear as i f th e t ime of on set of
NMB is shorter ( 197 , 19 8 , 19 9 ) . The output of the s t imulator should be increased
unt i l the response does not increase with increasing current , then increased 10% to
20%. If maximal s t imulat ion is not achieved with a current of 50 to 70 mA, the
electrodes should be checked for proper placement. I f maximal s t imulat ion s t i l l
cannot be achieved, needle electrodes should be used.
Special needle electrodes are avai lable commercial ly, but ordinary inject ion
needles can be used. They should be short and thin. The needles should be placed
subcutaneously. Inserting them deeper may produce direct muscle excitation and/or
cause damage to the nerve. The angle of inser t ion should be paral lel to the nerve.
There should be at least a few cent imeters between the needles. They should be
fixed in place with tape. The lead should be attached to the shaft of the needle
unless the needle has a metal hub.
Correct EMG electrode placement should be ver i f ied by observing the qual i ty of the
evoked waveform, which should approximate a s ine wave. The gain control should
be adjusted so that the waveform occupies the ful l s cale.
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I n t u b a t i o n
Complete relaxat ion of the jaw, laryngeal and pharyngeal muscles , and diaphragm
is needed for excel lent intubat ing condi t ions and to reduce the r isk of t rauma. I t
should be kept in mind that the response to intubat ion is a funct ion of both
muscular block and the level of anesthesia . I t
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is possible to intubate a pat ient with less- than-complete paralysis i f a suff icient
depth of anesthesia is present ( 200 ) .
View Figure
Figure 25.18 Electrodes in place. Creating loops andsecuring the wires with tape will decrease the likelihood thatthe wires will be pulled off the electrodes.
The onset of NMB wil l be faster in central ly located muscles such as the
diaphragm, facial , laryngeal , and jaw muscles than per ipheral muscles such as the
adductor pol l icis ( 11 0 ,19 0 , 201 , 20 2 ,20 3 ,204 , 205 ,206 ,207 ,20 8 , 20 9 ,210 ).
The diaphragm, eye muscles , and most laryngeal muscles are more resis tant to
nondepolar izing relaxants than are per ipheral muscles ( 211 , 21 2 ). The diaphragm isresis tant to succinylchol ine, though the laryngeal muscles are sensi t ive to i t . The
masseter muscle is relat ively sensi t ive to both nondepolar izing and depolar izing
relaxants ( 192 ,21 3 ). It often reacts with increased tone instead of relaxation to
succinylchol ine, par t icular ly in chi ldren.
Monitoring the response of the eye muscles will reflect the time of onset and the
level of NMB at the ai rway musculature more closely than monitor ing per ipheral
muscles , which wil l underest imate the rate of onset of NMB in the ai rway
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musculature and may overest imate the degree of block
(163 , 17 9 ,202 , 214 , 21 5 , 21 6 ,217 , 218 ).
If the facial nerve cannot be used, a per ipheral nerve wil l suff ice in most cases. Inthe majori ty of pat ients , disappearance of the adductor pol l icis response is
associated with good to excellent intubating conditions. If the electromyographic
responses are being monitored, monitor ing at the hypothenar eminence may be
preferable ( 157 ).
Whatever nerve is used, i t i s recommended that s ingle twitch at 0.1 Hz be used and
that the cl inician wai t unt i l a response is barely percept ible before at tempting
laryngoscopy and intubation. More rapid stimulation may accelerate the onset of
block at the s t imulated s i te ( 198 ,19 9 ) . Double burst has been used as a n indicator
of opt imal condi t ions for t racheal intubat ion ( 219 ).
The response to s t imulat ion wil l usual ly disappear for a v ar iable per iod of t ime,
then appear and increase progressively to ful l recovery. Addi t ional relaxants should
not be given unt i l there is evidence of some recovery to make sure that the pat ient
does not have an abnormal response. However, i t i s not necessary to wai t for
complete recovery before giving addi t ional relaxants .
E le c t r o c o n v u l s i v e T h e r ap y
A comm on erro r in elec tr oc onv ul s ive therap y is del iv eri ng the el ec tri cal s timu lus
prematurely ( 220 ) . I t i s recommended that a s ingle s t imulus be appl ied at 1 Hz to
the poster ior t ibial nerve ( 22 1 ) . When there is c omplete abol i t ion of response, the
electroconvulsive therapy should be appl ied.
M a i n t e n a n c e
During maintenance, the stimulator can be used to ti trate the relaxant dosage to the
needs of the operat ive procedure so both under- and overdosage are avoided. Too
deep an NMB may make i t di ff icul t to reverse the relaxant at the terminat ion of the
anesthet ic . Underdosage may resul t in inadequate relaxat ion or undesirable pat ientmovement . In a s tudy of closed c laims against anesthesiologists , eye injur ies
const i tuted 3% of claims ( 22 2 ). Patient movement during anesthesia was the
mechanism of injury in 30% of those cases. Peripheral nerve stimulators were not
used in any pat ients who made claims for movement under anesthesia .
The degree of NMB required during a surgical procedure depends on many factors,
including the type of surgery, the anesthet ic technique, and the depth of
anesthesia . I t i s important to prevent cool ing of the monitor ing si te to avoid
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impaired nerve conduct ion or increased skin resis tance, which may resul t in
overestimation of the degree of NMB ( 26 , 223 , 22 4 ) .
I t i s important to correlate the react ion to nerve s t imulat ion with the pat ient 'scl inical condi t ion because there may be a discrepancy between the degree of
relaxat ion of the monitored muscles and that of the muscles at the s i te of surgery.
If the surgeon bel ieves that relaxat ion is inadequate, the anesthesia provider
should confirm that the depth of anesthesia is s uff icient and the degree of NMB is
adequate. I t should be confirmed that the s t imulator is working properly. I f i t does
not display the del ivered current , e lectrodes may be placed on the user 's arm and a
low current used to confirm proper funct ion.
TOF is c ommonly regarded as the most useful pat tern for monitor ing NMB during
maintenance. Supramaximal currents are t radi t ional ly used. A submaximal current
may be used, but this is controversial ( 15 , 18 , 19 , 30 ,10 4 ,225 ,22 6 ) . The goal for most
cases in which abdominal muscle relaxat ion is required should be to maintain at
least one response to TOF st imulat ion in a per ipheral nerve ( 227 ,228 ) . I f no
response is present , fur ther administ rat ion of relaxants is not indicated. I f two
responses are present , abdominal relaxat ion may be adequate using balanced
anesthesia ( 229 ). Presence of three twitches is usually associated with adequate
relaxat ion i f a volat i le anesthet ic agent is used. Deeper levels of NMB may be
required for upper abdominal or chest surgery or i f diaphragmatic paralysis isneeded. I f the facial muscles are used, a t least one twitch should be added to the
mentioned recommendations.
Muscle relaxants are sometimes administered in cases such as eye surgery or laser
surgery on the vocal co rds to guarantee that movement does not occur. To ensure
total diaphragmatic paralysis , the NMB should be so intense that there is no
response to post- tetanic
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st imulat ion ( i .e . , the PTC is 0) ( 230 ,231 ) . One approach is to give a bolus of a
short-act ing muscle relaxant when the PTC is 1 ( 23 2 ) . Al ternat ively, the twitch
response at a resis tant muscle such as the orbicular is ocul i may be monitored and
a dose of relaxant given as soon as there is any response.
R e c o v e r y a n d R ev e r s a l
At the end of a p ro cedu re, a s t imul ato r al lows the an es th es ia prov ider to de termi ne
whether or not the block is reversible and adjust the dose of reve rsal agent , i f
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required, to the pat ient 's requirements ( 233 ) . Numerous s tudies have shown that
some pat ients enter ing the postanesthesia care uni t have an unacceptable lev el of
block(69 ,234 , 235 ,236 ,237 ,238 ,239 ,240 ,241 ,242 ,243 ,244 , 245 ,246 ,24 7 ,248 ,24 9 , 25 0 ,25 1 ,2
52 ,253 ) . A nerve s t imulator may detect residual NMB, which could lead to l i fe-
threatening c omplicat ions ( 74 , 254 , 25 5 , 25 6 ,257 , 258 ).
When relaxat ion is no longer required, administ rat ion of NMB drugs should be
discont inued. As recovery progresses, the responses to TOF wil l progressively
appear, then fade wil l disappear. The ease of reversing a nondepolar izing block is
inversely related to the degree of block at the t ime of reversal ( 6 ,259 ) . I f the f i rs t
twitch (T 1 ) is present , i t can be est imated how quickly the block can be reversed.
The t ime depends on the relaxant that has been used.
Recovery is governed by the sensi t ivi ty of the muscle and rate that the drug
disappears f rom the plasma. I t i s best to use a per ipheral muscle to monitor
recovery, because i ts complete recovery would indicate that residual muscular
weakness contr ibuting to problems with ai rway patency or respirat ion is u nl ikely
(110 , 18 8 ,202 , 205 , 26 0 , 26 1 ,262 ) . The probabi l i ty of detect ing fade by using the
index f inger is greater than i f the thumb or great toe is used ( 71 , 73 ).
In the past , many invest igators thought that a T OFR of 0.7 was adequate ( 4 , 26 3 ).
However, a normal response to hypoxemia, protect ion from pulmonarycomplicat ions, and absence of heaviness of the eyel ids, visual dis turbances,
diff icul ty swal lowing, or pat ient anxiety may require a higher rat io
(4 ,264 ,265 , 26 6 ,267 ,26 8 ,26 9 ,27 0 ,271 ,27 2 ,27 3 ). Most investigators now recommend
that the TOFR at the adductor pol l icis be at least 90% measured by
mechanomyography before extubation ( 24 8 ,266 ,275 , 276 ) . This is probably most
rel iably accomplished by using ACG and achieving a TOFR at least 90% of the
basel ine ( 68 ,91 , 92 ,254 , 257 , 27 7 ,278 ,279 , 280 ) . I f EMG monitor ing is being used,
residual anesthet ic effects usual ly p revent the return of T 1 to the preanesthetic
reference level, but the TOFR should exceed 90% ( 281 ).
Residual NMB cannot be rel iably detected by using TOF st imulat ion i f visual and/or
tact i le monitor ing is used ( 19 ) . Detect ion may be somewhat bet ter when using DBS
(30 ,31 ,52 , 28 2 ) . Both may be more rel iable at detect ing fade at lower currents ( 19 ).
Cl inical cr i ter ia in an awake pat ient have been used to ascer tain whether the return
of muscle s t rength is adequate. These include the abi l i ty to (a) open the eyes for 5
seconds and not experience diplopia, (b) sustain tongue protrusion, (c) sustain
head l i f t for at least 5 s econds, (d) sustain hand gr ip, (e) sustain leg l i f t ing in
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chi ldren, ( f ) cough effect ively, and (g) swal low. A more sensi t ive test may be the
abi l i ty to resis t removing a tongue blade from clenched teeth ( 268 ) . Cl inical cr i ter ia
in an asleep pat ient include an adequate t idal volume and an inspiratory force of atleast 25 cm H 2 O negat ive pressure. Subject ing the pat ient to negat ive inspiratory
pressure can cause pulmonary edema. These cl inical c r i ter ia do not exclude
cl inical ly s ignif icant residual paralysis ( 24 8 ,272 ,283 ).
P o s t o p e r at i v e Pe r i o d
Even i f a nerve s t imulator has not been used during an operat ion, i t can be used
postoperatively. I f the pat ient is not ful ly anesthet ized, i t i s preferable to use less
than supramaximal s t imulat ion ( 15 ,29 ,284 ). This decreases the discomfort
associated with s t imulat ion and may improve the visual assessment accuracy ( 30 ).
L o n g - t er m M u s c l e Re la x an t In f u s i o n s
Long-term muscle relaxants infusions are sometimes used in cr i t ical care areas.
NMB monitoring should be used to avoid overdosage
(285 , 28 6 ,287 , 288 , 28 9 , 29 0 ,291 , 292 ) . A number of factors unique to the cr i t ical care
set t ing affect the response to NMB drugs ( 12 , 28 6 ) . Prolonged paralysis is
sometimes se en despi te monitor ing ( 293 , 29 4 ) .
N er v e L o c a t i o n
A perip he ral nerv e s timu la to r may be us ed to lo cate nerv es f or re gional b lo ck ( 295 ).
The current needed is far below that needed for monitoring NMB. Stimulators with
different current outputs for both funct ions are avai lable ( 296 , 297 ).
Hazards
B u r n s
Burns have been reported when using a s t imulator with metal bal l e lectrodes ( 29 8 ) .
Needle electrodes may be associated with local t issue burns from electrosurgical
uni ts because they provide good contact with minimal resis tance for exi t of high-
frequency current over a smal l area of sk in ( 299 ) . Severe burns resul t ing in
permanent loss of hand funct ion caused by a nerve s t imulator have been reported
(300 ) .
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N e r v e D am a g e
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The pressure of an electrode on a nerve can resul t in palsy ( 154 ). Thumb
paresthesias were reported in pat ients whose muscular funct ion was monitored by
using an MMG ( 301 ) . Nerve damage can resul t f rom intraneural placement of aneedle electrode.
C o m p l i c a t i o n s A s s o c i a t ed w i t h N ee d l e E l ec t r o d e s
Complicat ions associated with needle electrodes include infect ion, bleeding, and
pain.
P a i n
Pat ient discomfort wil l be reduced by using lower currents and avoiding tetanic or
double-burst stimulation when the patient is not fully anesthetized ( 16 ,18 ).
E l ec t r i c a l I n t e r f e r e n c e
The use of a nerve s t imulator may cause changes in the ECG tracing or interfere
with an implanted pacemaker ( 302 ,303 , 30 4 ,305 ).
In c o r r e c t In f o r m a t io n
With some st imulators , when the bat ter ies are low, only three pulses are generated
during TOF st imulat ion ( 306 ) . This could lead to incorrect interpretat ion of the
degree of NMB.
A pote nt iall y con fus in g user interfac e on a neu rom uscular tr ans mis sion mod ule ha s
been reported ( 307 ) . The module provided a bar graph visual indicat ion of the four
responses to TOF stimulation. However, if the responses were greater than 120% of
the control response, the bar graph representat ions were chopped off . As a resul t ,
a l l four t witches could appear to be of the same height when the TOF rat io was
below 100%.
References1. Viby-Mogensen J . Monitoring of neuromuscular blockade: technology and cl inical
methods. In: Agoston S, Bowman WC, eds. Muscle relaxants . New York: Elsevier,
1 990 :14 1 162 .
2. Viby-Mogensen J . Postoperat ive residual curar izat ion and evidence-based
anaes thes ia . Br J Anaes th 2000;84:301303.
[Medline Link]
3. Mart in R, Bourdua I , Theriaul t S, et a l . Neuromuscular monitor ing: does i t make a
di ffe rence? Can J Anaes th 1996;43:585588.
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
33/74
4. Donat i F. Neuromuscular monitor ing: useless , opt ional or mandatory? Can J
Anaes th 19 98;45 :R1 06-R 11 1.
5. Torda TA. Monitoring neuromuscular transmission. Anaesth Intens Care 2002;30:123133.
[Medline Link]
6. Kopman AF, Zank LM, Ng J, et al . Antagonism of cisatracurium and rocuronium
at a tact i le t rain-of-four of 2: should quant i tat ive assessment of neuromuscular
func tion be mandatory? Anes th Analg 2004;98:1026.
7. Bai l lard C, Clec 'h C, Cat ineau J , e t a l . Postoperat ive residual neuromuscular
b lock: a survey of management . Br J Anaes th 2005;95:622626.
[Ful l text Link]
[CrossRef]
[Medline Link]
8. Kopman AF, Lawson D. Milliamperage requirements for supramaximal stimulation
of the ulnar nerve with surface electrodes. Anesthesiology 1984;61:8385.
[Medline Link]
9. Sai toh Y, Narumi Y, Fuj i i Y, et a l . Relat ionship between st imulat ing current and
accelographic train-of-four response at the great toe. Anaesthesia 1999;54:1097
1099.
10. Brul l SJ. Muscle relaxants: what should I monitor and what does i t te l l me?(ASA Ref resher Course). Park Ridge , IL: ASA, 1999.
11. Harper NJN, Greer R, Conway D. Neuromuscular monitoring in intensive care
pat ients: mil l iamperage requirements for supramaximal s t imulat ion. Br J Anaesth
2 00 1; 87 :6 25 6 27 .
[Ful l text Link]
[CrossRef]
[Medline Link]
12. Harper NJN. Neuromuscular blocking drugs: pract ical aspects of research in the
in tens ive care uni t . In tens ive Care Med 1993;19:580585.
13. Saitoh Y, Kamneda K, Hattori H, et al . Monitoring of neuromuscular block after
administ rat ion of vecuronium in pat ients with diabetes mel l i tus . Br J Anaesth
2 00 3; 90 :4 80 4 86 .
[Ful l text Link]
[CrossRef]
[Medline Link]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
34/74
14. Edmonds HL Jr, Paloheimo M, Wauquier A. Computerized EMG monitoring in
anesthesia and intensive care. Schoutlaan, The Netherlands: Instrumentarium
Sc ience Foundat ion , 1988 .15. Brul l SJ, Ehrenwerth J , Si lverman DG. St imulat ion with submaximal current for
t ra in-of -four moni tor ing . Anes thes io logy 1990;72:629632.
[Ful l text Link]
[CrossRef]
[Medline Link]
16. Connel ly NR, Si lverman DG, O'Conner TZ, et al . Subject ive responses to t rain-
of-four and double burst stimulation in awake patients. Anesth Analg 1990;70:650
653.
[CrossRef]
[Medline Link]
17. Sai toh Y, Toyooka H. Optimal s t imulat ing current for t rain-of-four s t imulat ion in
consc ious subjec ts . Can J Anaes th 1995;42:992995.
[Medline Link]
18. Brul l SJ, Si lverman DG. Pulse width, s t imulus intensi ty, e lectrode placement ,
and polar i ty during assessment of neuromuscular block. Anesthesiology
1 99 5; 83 :7 02 7 09 .
[Ful l text Link] [CrossRef]
[Medline Link]
19. Brul l SJ, Si lverman DG. Visual and tact i le assessment of neuromuscular fade.
Anes th Anal g 1993 ;77:35 23 55 .
[Medline Link]
20. Viby-Mogensen J , Engbaek J , Eriksson LI , et a l . Good cl inical research pract ice
(GCRP) in pharmacodynamic studies of neuromuscular blocking agents. Acta
Anaes th es io l Sc and 199 6;40 :5 9 74.
[Medline Link]
21. Meretoja OA, Taivainen T, Brandom BW, et al . Frequency of train-of-four
st imulat ion inf luences neuromuscular response. Br J Anaesth 1994;72:686687.
[CrossRef]
[Medline Link]
22. Heier T, Caldwell JE, Sessler KL, et al . The relat ionship between adductor
pol l icis twi tch tension and core, skin and muscle temperature during ni t rous oxide-
i sof lurane anes thes ia in humans . Anes thes io logy 1989;71:381384.
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
35/74
[Ful l text Link]
[CrossRef]
[Medline Link] 23. Heier T, Caldwell JE, Sessler DI, et a l . The effect of local surface and central
cool ing on adductor pol l icis twi tch tension using ni t rous oxide/ isof lurane and
ni t rous oxide/fentanyl anesthesia in humans. Anesthesiology 1990;72:807811.
[Medline Link]
24. England AJ, Wu X, Feldman SA. Effect of temperature on the sensi t ivi ty of
t ransducers used on human volunteers during neuromuscular s t imulat ing
experiments? Anaes thesia 1994;49:554.
25. Eriksson LI, Lennmarken C, Jensen E, et al . Twitch tension and train-of-four
rat io during prolonged neuromuscular monitor ing at different per ipheral
t empera tures . Acta Anaes thes io l Scand 1991;35:247252.
[Medline Link]
26. Heier T, Caldwell JE. Impact of hypothermia on the response to neuromuscular
b locking drugs . Anes thes io logy 2006;104:10701080.
[Ful l text Link]
[CrossRef]
[Medline Link]
27. Ali HH, Utt ing JE, Gray C. St imulus frequency in the detect ion of neuromuscularb lock in humans . Br J Anaes th 1970;42:967978.
[CrossRef]
[Medline Link]
28. Bayly PJM. Frequency of repeated neuromuscular s t imulat ion. Anaesthesia
1 990 ;45 :1 71 .
[CrossRef]
[Medline Link]
29. Si lverman DG, Connel ly NR, O'Connor TZ, et al . Accelographic t rain-of-four at
near- threshold cur rents . Anes thes io logy 1992;76:3438.
[Ful l text Link]
[CrossRef]
[Medline Link]
30. Brul l SJ, Si lverman DG. Visual assessment of t rain-of-four and double burst
induced fade a t submaximal s t imula t ing cur rent s . Anes th Analg 1991;73:627632.
[Ful l text Link]
[CrossRef]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
36/74
[Medline Link]
31. Drenck NE, Ueda N, Olsen V, et al . Manual evaluat ion of residual curar izat ion
using double burst s t imulat ion. A comparison with t rain-of-four. Anesthesiology1 98 9; 70 :5 78 5 81 .
[Ful l text Link]
[CrossRef]
[Medline Link]
32. Gil l SS, Donat i F, Bevan DR. Cl inical evaluat ion of double-burst s t imulat ion. I ts
re la t ionship to t rain-of- four s t imula t ion . Anaes thesia 1990;45:543548.
[CrossRef]
[Medline Link]
33. Saddler JM, Bevan JC, Donat i F, et a l . Comparison of double-burst and t rain-of-
four s t imulat ion to assess neuromuscular blockade in chi ldren. Anesthesiology
1 99 0; 73 :4 01 4 03 .
[Ful l text Link]
[CrossRef]
[Medline Link]
34. Tammisto I , W irtavouri K, Linko K. Assessment of neuromuscular block:
comparison of three cl inical me thods and evoked electromyography. Eur J Anaesth
1 988 ;5 :1 8 .[Medline Link]
35. Brul l SJ, Si lverman DC. Real t ime versus s l ow-motion t rain-of-four monitor ing: a
theory to explain the inaccuracy of visual assessment . Anesth Analg 1995;80:548
551.
[Ful l text Link]
[CrossRef]
[Medline Link]
36. Dupuis Y, Tessonnier JM. Clinical assessment of the muscular response to
te tanic nerve s t imula t ion . Can J Anaes th 1990;37:397400.
[Medline Link]
37. Baurain MJ, Hennart DA, Godschalx A, et al . Visual evaluat ion of residual
curar izat ion in anesthetized pat ients using one hundred-Hertz, f ive-second tetanic
s t imula t ion a t the adductor pol l i c is musc le . Anes th Analg 1998;87:185189.
[Ful l text Link]
[CrossRef]
[Medline Link]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
37/74
38. Fernandes LA, Stout RG, Silverman DG, et al . Comparative recovery of 50-Hz
and 100-Hz post tetanic twitch fol lowing profound neuromuscular block. J Cl in
Anes th 199 7;9:48 5 1.[CrossRef]
[Medline Link]
39. Brul l SJ, Connel ly NR, O'Connor TZ, et al . Effect of tetanus on subsequent
neuromuscular monitoring in patients receiving vecuronium. Anesthesiology
1 991 ;7 4:6 47 0.
[Ful l text Link]
[CrossRef]
[Medline Link]
40. Si lverman DG, Brul l SJ. The effect of a tetanic s t imulus on the response to
subsequent t e tan ic s t imula t ion . Anes th Analg 1993;76:12841287.
[Medline Link]
41. Sai toh Y, Masuda A, Toyooka H, et al . Effect of tetanic s t imulat ion on
subsequent t rain-of-four responses at var ious levels of vecuronium-induced
neuromuscular b lock . Br J Anaes th 1994;73:416417.
[CrossRef]
[Medline Link]
42. Viby-Mogensen J , Howardy-Hansen P, Chraemmer-Jorgensen B, e t a l .Posttetanic count (PTC). A new method of evaluating intense nondepolarizing
neuromuscular b lockade. Anes thes io logy 1981;55:458461.
[Ful l text Link]
[CrossRef]
[Medline Link]
43. Viby-Mogensen J , Bonsu AK, Muchhal FK, et al . Monitor ing of intense
neuromuscular b lockade caused by a t racurium. Br J Anaes th 1986;58:68S.
44. Gwinnut t CL, Meakin G. Use of the post- tetanic count to monitor recovery from
intense neuromuscular b lockade in chi ldren. Br J Anaes th 1988;61:547550.
[CrossRef]
[Medline Link]
45. Eriksson LI , Lennmarken C, Staun P, et a l . Use of post- tetanic count in
assessment of a repet i t ive vecuronium-induced neuromuscular block. Br J Anaesth
1 99 0; 65 :4 87 4 93 .
[CrossRef]
[Medline Link]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
38/74
46. Bonsu AK, Viby-Mogensen J , Fernando PUE, et al . Relat ionship of post- tetanic
count and t rain-of-four response during intense neuromuscular blockade caused by
a t racur ium. Br J Anaes th 1987;59:10891092.[CrossRef]
[Medline Link]
P.822
47. El-Orbany MJ, Joseph NJ, Salem MR. The relationship of posttetanic count and
train-of-four responses during recovery from intense c isatracurium-induced
neuromuscular b lockade . Anes th Analg 2003;97:8084.
[Ful l text Link]
[CrossRef]
[Medline Link]
48. Muchhal KK, Viby-Mogensen J, Fernando PUE, et al . Evaluation of intense
neuromuscular blockade caused by vecuronium using posttetanic count (PTC).
Anes th es iolog y 1987 ;66 :8 46 84 9 .
[Ful l text Link]
[CrossRef]
[Medline Link] 49. Baykara N, Solak M, Toker K. Predict ing recovery f rom deep neuromuscular
b lock by rocuronium in the e lder ly. J Cl in Anes th 2003;15:328333.
[CrossRef]
[Medline Link]
50. Saitoh Y, Nakazawa K, Makita K, et al . Evaluation of residual neuromuscular
blockade using modif ied double burst s t imulat ion. Acta Anaesthesiol Scand
1 997 ;4 1: 7 4 17 45 .
[Medline Link]
51. Ueda N, Viby-Mogensen J , Viby-Olsen N, et al . The best c hoice of double burst
s t imulat ion pat tern for manual ev aluat ion of neuromuscular t ransmission. J Anesth
1 989 ;3 :9 499 .
[Medline Link]
52. Engbaek J , Os tergaard D, Viby-Mogensen J . Double burst s t imulat ion (DBS). A
new pat tern of nerve s t imulat ion to ident i fy residual neuromuscular block. Br J
Anaes th 19 89;62 :27 4 27 8.
[CrossRef]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
39/74
[Medline Link]
53. Braude N, Vyvyan HAL, Jordan MJ. Intraoperative assessment of atracurium-
induced neuromuscular block using double burst s t imulat ion. Br J Anaesth 1991;67:574578.
[CrossRef]
[Medline Link]
54. Si lverman DG, Sorin I , Brul l J . Pat terns of s t imulat ion in neuromuscular block in
perioperat ive and intensive care. Phi ladelphia: JB Lippincot t , 1994:3750.
55. Saitoh Y, Nakazawa K, Tanaka H, et al . Double burst stimulation 2 , 3 : a new
stimulating pattern for residual neuromuscular block. Can J Anaesth 1996;43:1001
1005.
[Medline Link]
56. Kirkegaard-Nielsen H, Helbo-Hansen HS, Lindholm P, et a l . Double burst
monitor ing during surgical degrees of neuromuscular blockade: a comparison with
t ra in-of -four. In t J Cl in Moni t Comput 1995;12:191196.
[CrossRef]
[Medline Link]
57. Kirkegaard-Nielsen H, Helbo-Hansen H, S everinsen I , e t a l . Response to double
burst appears before response to t rain-of-four s t imulat ion during recovery from non-
depolar izing neuromuscular blockade. Acta Anaesthesiol Scand 1996;40:719723.[Medline Link]
58. Kirkegaard-Nielsen H, Helbo-Hanses HS, Severinsen IK, et al . Comparison of
tactile and mechanomyographical assessment of response to double burst and
train-of-four stimulation during moderate and profound neuromuscular blockade.
Can J Anaes t h 1995 ;42 :2127 .
[Medline Link]
59. Kirkegaard-Nielsen H, Helbo-Hansen HS, Lindholm P, et a l . Stabi l izat ion of the
neuromuscular response when switching between different modes of nerve
st imulat ion at surgical degrees of neuromuscular blockade. J Cl in Monit
1 99 5; 11 :3 17 3 23 .
[CrossRef]
[Medline Link]
60. Lippmann M, Fields WA. Burns of the skin caused by a per ipheral-nerve
s t imula tor. Anes thes io logy 1974;40:8284.
[Ful l text Link]
[CrossRef]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
40/74
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
41/74
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
42/74
[Medline Link]
79. Jensen E, Viby-Mogensen, Bang U. The accelograph: a new neuromuscular
t ransmiss ion moni tor. Acta Anaes thes io l Scand 1988;32:4952.[Medline Link]
80. Viby-Mogensen, Jensen E, Werner M, et al . Measurement of acceleration; a
new method of monitoring neuromuscular function. Acta Anaesth Scand
1 988 ;3 2:4 54 8.
[Medline Link]
81. Dubois PE, Broka SM, Joucken KL. TOF-tube. Anesth Analg 2000;90:232233.
[Ful l text Link]
[CrossRef]
[Medline Link]
82. Ueda N, Muteki T, Poulsen A, et al . Clinical assessment of a new
neuromuscular t ransmission monitor ing system (Accelerograph) . Jpn J Anesth
1 989 ;3 :9 093 .
83. Werner MU, Nielsen HK, May O, e t al . Assessment of neuromuscular
t ransmission by the evoked accelerat ion response. Acta Anaesthesiol Scand
1 98 8; 32 :3 95 4 00 .
[Medline Link]
84. May O, Nielsen HK, Werner MU. The acceleration transduceran assessmentof i ts precis ion in comparison with a force displacement t ransducer. Acta
Anaes th es io l Sc and 198 8;32 :2 39 243.
[Medline Link]
85. Meretoja OA, Brown WA, Cass NM. Simultaneous monitoring of force,
acceleration and electromyogram during computer-controlled infusion of atracurium
in sheep. Anaes th In tens Care 1990;18:486489.
[Medline Link]
86. I tagaki T, Tai K, Katsumata N, et al . Comparison between a new accelerat ion
transducer and a convent ional force t ransducer in the evaluat ion of twitch
responses . Acta Anaes thes iol Scand 1988;32:347349.
[Medline Link]
87. Loan PB, Paxton LD, Mirakhur RK, et al . The TOF-Guard neuromuscular
transmission monitor. A comparison with the Myograph 2000. Anaesthesia
1 99 5; 50 :6 99 7 02 .
[CrossRef]
[Medline Link]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
43/74
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
44/74
95. Nakata Y, Goto T, Saito H, et al . Comparison of acceleromyography and
electromyography in vecuronium-induced neuromuscular blockade with xenon or
sevoflurane anes thes ia . J Cl in Anes th 1998;10:200203.[CrossRef]
[Medline Link]
96. Chris tophe B, Sylvie B, Phi l ippe LT, et al . Assessing residual neuromuscular
blockade using acceleromyography can be d ecept ive in postoperat ive awake
pat ien t s . Anes th Analg 2004;98:854857.
[Ful l text Link]
[CrossRef]
[Medline Link]
97. Brul l SJ, Paloheimo M. A pract ical guide to monitor ing neuromuscular
func tion.
98. Dahaba AA, von Klubucar F , Rehak PH, et al . The n euromuscular t ransmission
module versus the Relaxometer mechanomyograph for neuromuscular block
moni tor ing . Anes th Analg 2002;94:591596.
[Ful l text Link]
[CrossRef]
[Medline Link]
99. Trager G, Michaud G, Deschamps S, et al . Comparison of phonomyography,kinemyography and mechanomyography for neuromuscular monitoring. Can J
Anes th 200 6;53 :1 30 1 35 .
100. Kern SE, Johnson JO, Westenskow DR, et al . An effective study of a new
piezoelectric sensor for train-of-four measurement. Anesth Analg 1994;78:978
982.
[Ful l text Link]
[CrossRef]
[Medline Link]
101. Johnson JO. A piezoelectr ic neuromuscular monitor in response. Anesth Analg
1 99 4; 79 :1 21 0 12 11 .
[Ful l text Link]
[CrossRef]
[Medline Link]
102. Roberts C, Dorsch JA. ParaGraph muscle stimulator: new approach to
placement . Anes thes io logy 1996;85:12181219.
[Ful l text Link]
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
45/74
[CrossRef]
[Medline Link]
103. Brandom BW, Lloyd ME, Woelfel SK, et al . Comparison of the Datex E MG andParagraph monitors during recovery from pancuronium in anesthet ized pediatr ic
pa ti ent s . Anes th Ana lg 1997 ;84 :S228 .
104. Kern SE, Johnson JO, Westenkow DR, et al . A comparison of dynamic and
isometr ic force sensors for t rain-of-four measurement using submaximal s t imulat ion
cur rent . J Cl in Moni t 1995;11:1822.
[CrossRef]
[Medline Link]
105. Dahaba AA, Klobucar FV, Rehak PH, et al . Comparison of a new piezoelectric
train-of-four neuromuscular monitor, the ParaGraph, and the Relaxometer
mechanomyograph. Br J Anaes th 1999;82:780782.
[Medline Link]
106. Lekowski RW, Johnston JF. Cl inical use of the Relaxograph NMT-100.
Anes th es iol Rev 19 94 ;21 :2 226 .
[Medline Link]
107. Paloheimo M. Quant i tat ive surface electromyography (qEMG): appl icat ions in
anaesthesiology and crit ical care. Acta Anaesthesiol Scand 1990;34[Suppl 93]:3
51.108. Sakabe T, Nakashima K. The Datex Relaxograph NMT-100. Anesthesiol Rev
1 990 ;1 7: 4 551 .
[Medline Link]
109. Paloheimo M, Edmonds HL Jr. Minimizing movement-induced changes in
twitch response during integrated electromyography. In reply. Anesthesiology
1 988 ;69 : 1 43 .
[Ful l text Link]
[CrossRef]
110. Hemmerling TM, Donati F. Neuromuscular blockade at the larynx, the
diaphragm and the corrugator superci l i i muscle: a review. Can J Anesth
2 00 3; 50 :7 79 7 94 .
111. Clancy E. A PC-based workstat ion for real- t ime acquisi t ion, processing and
display of e lec t romyogram s igna l s . Biomed Ins t rum Technol 1998;32:123134.
[Medline Link]
112. Smith DC, Booth JV. Influence of muscle temperature and forearm position on
evoked e lec t romyography in the hand. Br J Anaes th 1994;72:407410.
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
46/74
[CrossRef]
[Medline Link]
113. Ast ley BA, Katz RL, Payne JP. Electr ical and mechanical responses af terneuromuscular blockade with vecuronium, and subsequent antagonism with
neos tigmine or edrophonium. Br J Anaes th 1987;59:983988.
[CrossRef]
[Medline Link]
114. Carter JA, Arnold R, Yate PM, et al . Assessment of the Datex relaxograph
during anaesthesia and atracurium-induced neuromuscular blockade. Br J Anaesth
1 98 6; 58 :1 44 7 14 52 .
[CrossRef]
[Medline Link]
115. Engboek J , Ostergaard D, Viby-Mogensen J , e t a l . Cl inical recovery and t rain-
of-four rat io measured mechanical ly and electromyographical ly fol lowing
at racur ium. Anes thes iology 1989;71:391395.
[Ful l text Link]
[CrossRef]
[Medline Link]
116. Kopman AF. The effect of rest ing muscle tension on the dose-effect
relat ionship of d- tubocurar ine; does p reload inf luence the evoked EMG? Anes th es iolog y 1988 ;69 :1 00 31 005.
117. Kopman AF. The dose-effect relationship of metocurine. The integrated
electromyogram of the first dorsal interosseous muscle and the mechanomyogram
of the adductor pol l i ci s compared . Anes thes io logy 1988;68:604607.
[Ful l text Link]
[CrossRef]
[Medline Link]
118. Harper NJN, Bradshaw EG, Healy TEJ. Evoked electromyographic and
mechanical responses of the adductor pol l icis compared during the onset of
neuromuscular blockade by atracurium or alcuronium, and during a ntagonism by
neos tigmine . Br J Anaes th 1986;58:12781284.
[CrossRef]
[Medline Link]
P.823
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
47/74
119. Weber S, Muravchick S. Electrical and mechanical train-of-four responses
during depolar izing and nondepolar izing neuromuscular blockade. Anesth Analg
1 98 6; 65 :7 71 7 76 .[Ful l text Link]
[CrossRef]
[Medline Link]
120. Engbaek J , Roed J . Different ial effect of pancuronium at the adductor pol l icis ,
the f i rs t dorsal interosseous and the hypothenar muscles . An electromyographic
and mechanomyographic dose-response s tudy. Acta Anaesthesiol Scand
1 99 2; 36 :6 64 6 69 .
[Medline Link]
121. Engbaek J, Roes J, Hangaard N, et al . The agreement between adductor
pol l icis mechanomyogram and f i rs t dorsal interosseous electromyogram. A
pharmacodynamic study of rocuronium and vecuronium. Acta Anaesthesiol Scand
1 99 4; 38 :8 69 8 78 .
[Medline Link]
122. Engbaek J , Skovgaard LT, Fries B, et a l . Monitor ing of neuromuscular
transmission by electromyography (II). Evoked compound EMG area, amplitude and
durat ion compared t o mechanical twi tch recording during onset and recovery of
pancuronium-induced blockade in the cat. Acta Anaesthesiol Scand 1993;37:788798.
[Medline Link]
123. Engback J , Skovgaard LT, Fri is B, et a l . Monitor ing of the neuromuscular
transmission by electromyograph (I). Stabili ty and temperature dependence of
evoked EMG response compared to mechanical twi tch recordings in the c at . Acta
Anaes th es io l Sc and 199 2;36 :4 95 504.
124. Mort ier E, Moulaer t P, de Somer A, et al . Comparison of evoked
electromyography and mechanical act ivi ty during vecuronium-induced
neuromuscular b lockade . Eur J Anaes thes 1988;5 :131141.
125. Weber S, Muravchick S. Monitoring technique affects measurement of
recovery f rom succ inylchol ine . J Cl in Moni t 1987;3 :15.
[Medline Link]
126. Meretoja OA, Theroux M. Can final EMG baseline be used as a reference to
calculate neuromuscular recovery? Acta Anaesthesiol Scand 1997;41:492496.
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
48/74
127. Polhi l l S, Clewlow F, Smith D. Are changes in the evoked electromyogram
during anaesthesia without neuromuscular blocking agents caused by failure of
supramaximal nerve s t imula tion . Br J Anaes th 1998;81:902904.[Medline Link]
128. Gyermek L, Henderson G. Electromyographic monitoring of profound surgical
musc le re laxa t ion dur ing card iac anes thes ia . J Cl in Moni t 1992;8 :131135.
[CrossRef]
[Medline Link]
129. Hemmerl ing TM, Schmidt J , Wolf T, et a l . Surface vs intramuscular laryngeal
e lec tromyography. Can J Anaes th 2000;47:860865.
[Medline Link]
130. Hemmerling TM, Schurr C, Walter S, et al . A new method of monitoring the
effect of muscle relaxants on la ryngeal muscles using surface laryngeal
e lec tromyography. Anes th Analg 2000;90:494497.
[Ful l text Link]
[CrossRef]
[Medline Link]
131. Hemmerling TM, Schmidt J, Hanusa C, et al . Simultaneous determination of
neuromuscular block at the larynx, diaphragm, adductor pol l icis , orbicular is ocul i
and cor ruga ted superc i l i i musc les . Br J Anaes th 2000;85:856860.[CrossRef]
[Medline Link]
132. Hemmerling TM, Schmidt J, Hanusa C, et al . The lumbar paravertebral region
provides a novel s i te to assess neuromuscular block at the diaphragm. Can J
Anaes th 20 01;48 :35 6 36 0.
[Medline Link]
133. Hemmerl ing TM, Schmidt J , Wolf T, et a l . Intramuscular versus surface
electromyography of the diaphragm for determining neuromuscular blockade.
Anes th Anal g 2001 ;92:10 61 11 .
[Ful l text Link]
[CrossRef]
[Medline Link]
134. Hemmerl ing TM, Wolf T, Hanusa C, et a l . Intramuscular versus skin
electromyography (EMG) of the diaphragm: determination of the neuromuscular
b lock (NMB) af te r mivacurium. Anes thes io logy 2001;95:A1014.
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
49/74
135. Hemmerl ing TM, Schmidt J , Wolf T, et a l . Comparison of onset of
succinylchol ine vs. two doses of rocuronium with a new method of monitor ing
neuromuscular block at the laryngeal muscles using surface laryngeale lec tromyography. Br J Anaes th 2000;85:251255.
[CrossRef]
[Medline Link]
136. Atanassoff PG, Kel ly DJ, Ayoub CM, et a l . Electromyographic assessment of
u lnar nerve motor b lock induced by l idoca ine . J Cl in Anes th 1998;10:641645.
[CrossRef]
[Medline Link]
137. Dascalu A, Geller E, Moalem Y, et al . Acoustic monitoring of intraoperative
neuromuscular b lock . Br J Anaes th 1999;83:405409.
[Medline Link]
138. Michaud G, Trager G, Deschamps S, et al . Dominance of the hand does not
change the phonomyographic measurement of neuromuscular block at the adductor
pol l ic i s musc le . Anes th Analg 2005;100:718721.
[Ful l text Link]
[CrossRef]
[Medline Link]
139. Bel lemare F, Couture J , Donat i F, et a l . Temporal relat ion between acoust icand force responses at the adductor pol l icis d uring nondepolar izing neuromuscular
b lock . Anes thes iology 2000;93:646652.
[Ful l text Link]
[CrossRef]
[Medline Link]
140. Hemmerling TM, Michaud G, Trager G, et al . Phonomyography and
mechanomyography can be used interchangeably to measure neuromuscular block
a t the adductor pol l i c is musc le . Anes th Analg 2004;98:377381.
[Ful l text Link]
[CrossRef]
[Medline Link]
141. Hemmerling TM, Michaud G, Trager G, et al . Phonomyographic measurements
of neuromuscular blockade are similar to mechanomyography for hand muscles.
Can J Anes th 2004; 51 :795800 .
8/11/2019 Chapter 25. Neuromuscular Transmission Monitoring
50/74
142. Schmidt J , I ruschek A, Birkholz T, et a l . Comparison of phonomyography and
acceleromyography for neuromuscular monitoring in children. Anesthesiology
2 005 ;1 03 :A 112 7.143. Hemmerling TM, Michaud G, Babin D, et al . Comparison of phonomyography
with bal loon pressure mechanomyography to measure contract i le force at the
cor ruga tor superc i l i i muscle . Can J Anes th 2004;51:116121.
144. Hemmerling TM, Michaud G, Trager G, et al . Phonomyographic measurements
of neuromuscular blockade are similar to mechanomyography for hand muscles.
Can J Anes th 2004; 51 :795800 .
145. Hemmerling TM, Donati F, Beaulieu P, et al . Phonomyography of the
corrugator superci l i i muscle: s ignal character is t ics , best recording si te and
compar ison wi th acce le romyography. Br J Anaes th 2002;88:389393.
[Ful l text Link]
[CrossRef]
[Medline Link]
146. Hemmerling TM, Babin D, Donati F. Phonomyography as a novel method to
determine neuromuscular blockade at the laryngeal adductor muscles.
Anes th es iolog y 2003 ;98 :3 59 36 3 .
[Ful l text Link]
[CrossRef] [Medline Link]
147. Hemmerling TM, Michaud G, Deschamps S, et al . An external monitoring site
at the neck cannot be used to measure neuromuscular blockade of the larynx.
Anes th Anal g 2005 ;100 :1 718 172 2.
[Ful l text Link]
[CrossRef]
[Medline Link]
148. Iwasaki H, Yamauchi M, Narimatsu E, et al . Onset of vecuronium
neuromuscular blocka