NURSING PATIENT CARE POLICY & PROCEDURE
October 28, 2016
Nursing Manual (Red)
Policy #: 8.36AP
Title: Peripheral Nerve Stimulation (Adult &
To provide a nursing standard of care for patients receiving neuromuscular blocking
agents and to assure minimal number of skeletal muscle inhibition is blocked to
prevent neuropathy of the critically ill.
ξ Peripheral nerve stimulators (PNSs) are used to assess neuromuscular
transmission when neuromuscular blocking agents (NMBAs) are given to
block skeletal muscle activity.
ξ The muscle twitch response to an electrical stimulus delivered by the PNS
corresponds to the degree of nerve receptors blocked by NMBAs and assists
the clinician in the assessment and titration of medication dosage.
ξ The train of four (TOF) method of stimulation is most commonly used for
ongoing monitoring in the critical care unit.
A. A physician’s order must be obtained for all NMBAs. The PNS lead wires
connected to electrodes will be placed on all patients who receive continuous
infusions of NMBAs unless they are children less than 10 years of age.
1. < 1 year of age: Peripheral nerve stimulation is not reliable or
2. For age > 1 – 10 years of age: It may be reliable and you could try
peripheral nerve stimulation. If it does not work, stop using peripheral
nerve stimulation and use clinical exam. Do not increase the milliamps
on the PNS greater than 40.
C. All patients on NMBAs need concurrent sedation and pain control because
NMBAs cause sensation of being “paralyzed”. Patients need sedation and pain
control for the duration of these NMBAs to counteract this effect.
D. NMBA and PNS should only be performed in a critical care area.
A. PNS with two (2) lead wires
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B. Two (2) pre-gelled electrode pads (the same as those used for electrocardiography
C. Scissors for hair removal (if applicable)
A. Patient preparation/assessment
1. Clip hair at the electrode placement sites if necessary.
2. Assess the patient for the best location for electrode placement. Avoid
areas with edema, hair, diaphoresis, wounds, burns, topical ointments,
dressings, and arterial and venous catheters.
3. Assess the patient for a history of the presence of hemiplegia,
hemiparesis, or peripheral neuropathy.
B. Before initiation of NMBA and TOF
1. Perform hand hygiene according to UWHC Hospital Administrative
Policy 13.08, Hand Hygiene.
2. Cleanse and thoroughly dry the skin before applying electrodes.
3. Apply two (2) pre-gelled electrodes over the path of the nerve selected.
4. Use caution in selecting the site of the electrode placement in order to
avoid direct stimulation of the muscle rather than the nerve.
Nerve Electrode placement Assessment (visual/tactile)
Distal: (Black) Place electrode on the skin at the
flexor crease of the ulnar surface of the wrist, as
close to the nerve as possible.
Proximal: (Red) Place electrode approximately 1-
2cm proximal to the distal electrode; parallel to the
flexor carpi ulnaris tendon.
Determine twitching of the
Do not count finger
movements, only the thumb.
Distal: (Black) Place electrode approximately 2cm
posterior to the medial malleolus of the foot.
Proximal: (Red) Place the second electrode
approximately 2cm above the distal electrode.
Determine twitching of the
plantar flexion of the great toe
Distal (Black) Place electrode parallel with tragus
of the ear.
Proximal: (Red) Place electrode on the face at the
outer canthus of the eye.
Determine twitching of the
muscle above the eyebrow.
5. Plug in the lead wires to the nerve stimulator, matching the negative
(black) and positive (red) leads to the black and red connection sites.
The lead wires then should be connected to the electrodes. Connect the
negative (black) lead to the distal electrode. Connect the positive (red)
lead to the proximal electrode.
C. Always test TOF before initiating NMBAs to determine the supramaximal
stimulus (SMS), which is the baseline voltage needed to obtain four (4) twitches.
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To determine the SMS:
1. Turn ON the PNS and select a low mA (milliamperes) (10-20 mA is
typical). NOTE: Excessive current results in overstimulation and can
cause repetitive nerve firing.
2. Press the TOF key and through visual and tactile assessment, determine
3. Increase the mA dial in increments of one (1) and repeat TOF until four
(4) vigorous twitches are observed. (Allow 10 seconds before repeating.)
4. If an increase in intensity is observed, raise the mA again until no further
increase is observed. The SMS is the number previous to the one that
yielded no change.
5. Document the mA that corresponds to four vigorous twitches on nursing
D. Determine the TOF response during the NMBA infusion
1. The provider will prescribe the level of paralysis goal needed as
reflected by the number of twitches present. Ensure clinical exam
correlates with TOF.
a. Administer lowest dose NMBA dose possible to obtain goal
twitches or prescribed clinical goal.
b. If the number of twitches or level of paralysis is less than ordered,
increase the infusion rate as prescribed and retest every 10 -15
minutes until clinical goal is reached. Usual goal for therapy is one
to two (1-2) twitches or goal met as determined by provider.
c. Re-test every one to two (1-2) hours until the patient achieves
desired level of blockade and maintains it for 2 hours, and every
four to eight (4-8) hours thereafter.
d. Receptors and twitches:
i. Four (4) twitches signify that 70 percent or less are
blocked. Three (3) twitches correspond to approximately 75
ii. Two twitches corresponds to approximately 80 percent
iii. One twitch correlate with approximately -90 percent
blockade of receptors.
iv. Zero twitches indicates 100 percent blockade or PNS
failure which requires troubleshooting (see below)
E. Patient monitoring and care
1. Change the electrodes every 24 hours or when loose or when the gel
becomes dry. All patients receiving NMBA and PNS should receive
frequent eye, oral and skin care to avoid tissue injury.
2. Consider electrode site change if skin breakdown occurs.
3. All patients receiving NMBA should receive careful passive range of
motion minimally twice daily as patient tolerates and based upon
type/location of central line.
4. Never use the “single twitch,” “tetany,” or “double burst” settings if
available on the PNS.
5. Assess the patient’s oxygenation and ventilation, neurologic function,
and tissue perfusion prior to increasing the rate of the NMBA infusion.
6. Extreme caution must be exercised to prevent the PNS lead wires from
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contacting an external pacing catheter or pacing lead wires.
7. Upon discontinuation of NMBAs, PNS will be performed until complete
return of 4 twitches. Document time in the patient’s clinical record.
F. Troubleshooting when zero twitches present (after assessing the patient) and there
is indication that there is failure of the PNS
1. Change the battery in PNS.
2. Check the lead connections and the PNS for mechanical failure.
3. Change the electrodes and ensure that the patient’s skin is clean and dry.
4. Increase the stimulating current.
5. Re-test another nerve.
6. Assess the patient for edema, if the there is significant edema there could
be failure of the nerve to be stimulated.
7. If there are no other explanations for a zero response, check the NMBA
infusion for the rate, dose, and concentration. Reduce the infusion rate of
the NMBA as prescribed.
8. If the patient is a child less than 10 years of age report findings to
provider to decide if PNS is appropriate for this patient.
VI. UWHC CROSS REFERENCES
A. Continuous Infusion Neuromuscular Blocking Agents (NMBAs) -Adult –
Inpatient Clinical Practice Guideline
B. UW Health Adult ICU and ED Neuromuscular Blocking Agent Continuous
Infusion Delegation Protocol
C. Hospital Administrative Policy 13.08, Hand Hygiene
A. Alhazani, W>, Alsharani, M., Jaeschke, R., Forel, J.M., Papazian, L., Sevransky,
J., & Meade, M.O. (2013). Neuromuscular blocking agents in acute respiratory
distress syndrome: a systematic review and meta-analysis of randomized
controlled trials. Critical Care, 17(2): R43.
B. Chulay, M., & Burns, S. (2006). AACN Essentials of Critical Care Nursing. New
York, NY: McGraw Hill.
C. Corso, L (2008). Train-of-four results and observed muscle movement in children
during continuous neuromuscular blockade. Critical Care Nurse, 28(3), 30-38.
D. Greenberg, S.B. & Vender, J. (2013). The use of neuromuscular blocking agents
in the ICU: where are we now? Critical Care Medicine, 41(5):1332-44.
E. Lynn-McHale Wiegand, D. J., & Carlson, K. K. (2011). AACN procedure manual
for critical care (6th Ed.). St. Louis, MO: Elsevier Saunders Co.
F. Price, D.R., Mikkelsen, M.E., Umscheid, C.A., & Armstrong, E.J. (2016).
Neuromuscular blocking agents and neuromuscular dysfunction acquired in
critical care illness: a systematic review and meta-analysis. Critical Care
G. Puthucheary, Z., Rawal, J., Ratnayake, G. Harridge, S., Montgomery, H., & Hart,
N. (2012). Neuromuscular blockade and skeletal muscle weakness in critically ill
patients: time to rethink the evidence. American Journal of Respiratory Critical
Care Medicine, 185(9): 911-7.
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VIII. REVIEWED BY
Nurse Education Specialist, Critical Care
Clinical Nurse Specialist, Cardiac Surgery and Transplant
Clinical Nurse Specialist, Burn
Clinical Nurse Specialist, Trauma Life Support Center (TLC)
Clinical Nurse Specialist, Pediatric Intensive Care
Nursing Patient Care Policy and Procedure Committee, October 2016
Beth Houlahan, DNP, RN, CENP
Senior Vice President Patient Care Services, Chief Nursing Officer