J. Ross Renew MD FASA FASE

Associate Professor of Anesthesiology

Vice Chair of Research

Mayo Clinic Florida

@rossrenew

HOW TO IMPLEMENT QUANTITATIVE

NEUROMUSCULAR MONITORING

INTO YOUR PRACTICE

• Merck-funded research (funds to Mayo Clinic)

• Speaker for Senzime AB

Disclosures

To Do…

• Why should I care about monitoring?

• Recent advances in objective neuromuscular monitoring modalities

• Anesthesia 101: Monitoring Sites/ Patterns of Neurostimulation

• Practical considerations for introducing objective neuromuscular

monitors into practice

Consequences of Residual NMB

• Subjectively worse recovery

Murphy Anesthesiology 2011, Murphy A&A 2013, Murphy A&A 2021

• Hypoxemia

Murphy A&A 2008

• Impaired Pulmonary Function

Eikermann Chest 2005

• Upper airway obstruction

Sundman Anesthesiology 2000, Murphy A&A 2008

• Postop pneumonia

Berg Acta Anaesthesiol Scand 1997

• Respiratory failure

McLean Anesthesiology 2015

https://www.istockphoto.com/photo/large-stack-of-papers-gm184881173-18349926

Nomenclature

• Clinical assessment = 5 –sec head lift, grip strength, etc…

• Subjective evaluation = Peripheral nerve stimulator (PNS)

• Quantitative (objective) monitoring = monitor that

stimulates a peripheral nerve, measures the response to

stimulation, and converts this signal to objective data

Clinical Assessment

Cammu G, et al. Anesth Analg. 2006 Feb;102(2):426-9.

Peripheral Nerve Stimulator

Cannot reliably detect fade when TOFR > 0.4

• RD Miller Anesthesiology 1985

• SJ Brull A&A 1993

• Capron A&A 2006

Trouble counting twitches

• 50 patients, 666 neurostimulations

• Overestimated twitch count 47%

of the time

• Subjective evaluations were

higher than objective 92% of the

time

(95% CI, 87 to 95; P <

0.001)

Renew JR, et al. Can J Anaesth. 2023 May;70(5):878-885.

The Ideal Monitor

• Easy to setup/intuitive

• Cost effective

• Portable

• Integrates into EMR

• Adds value during all phases of

perioperative care

• Works in a variety of settings (ICU)

Mechanomyography

• Historic gold standard

• Measures force of isometric

contractions

• Force is converted to electrical

signal

Brull SJ, Murphy GS. Anesth Analg 111; 129-40, 2010

.

Acceleromyography (AMG)

• Most frequently studied

• Measures acceleration (requires freely

moving thumb)

• Can use ECG leads

• “Reverse fade”- baseline TOFR > 100%

• “Staircase phenomenon” – repetitive

stimulation increases amplitude of

muscle contraction (ST stimulation)

AMG

• 3D transducers can measure complex movement of thumb

• First modality to incorporate Bluetooth connectivity

• Recent efforts demonstrated good level of agreements

• Calibration, normalization, and preload application improved

agreement

Murphy GS, et al. Anesthesiology. 2018 Nov;129(5):880-888.

AMERICAN

SOCIETY

OF

ANESTHES

IOLOGIST

18

Can I still tuck the

arms?

AMERICAN

SOCIETY

OF

ANESTHES

IOLOGIST

19

Do I have to calibrate?

AMERICAN

SOCIETY

OF

ANESTHES

IOLOGIST

20

What about

normalization?

@ Extubation 90%

@ Baseline 119%

≈74%

119% X 0.9 ≈108%

Normalization Matters

• Bias between AMG devices is less with normalization

• Bias between AMG and EMG is less with normalization

• POPULAR study

• Utilized mostly uncalibrated, non-normalized AMG

• Post hoc analysis demonstrated raising threshold for

recovery to TOFR > 0.95 did reduce PPC

AMERICAN

SOCIETY

OF

ANESTHES

IOLOGIST

22

Murphy GS, et al. Anesthesiology. 2018 Nov;129(5):880-888.

Nemes R, et al. Anesthesiology 2021 Oct 1;135(4):597-611.

Kirmeier E, et al. Lancet Respir Med. 2019 Feb;7(2):129-140.

Blobner M, et al. Br J Anaesth. 2020 Jan;124(1):63-72.

Kinemyography (KMG)

• Similar to AMG

• Measures degree of bend of

piezoelectric sensor

• Large bias and wide limits of

agreement

• Not associated with reverse

fade

Khandkar C,et al. Anaesth Intensive Care. 2016;44:745–751.

Motamed C, et al. Eur J Anaesthesiol. 2003;20:467–469.

Electromyography (EMG)

• Measures action potentials (electrical

activity) of muscle after neurostimulation

• Does not require freely moving limbs

• Consistent responses over time and not

susceptible to changes in myofibril

contractility like AMG

• Results comparable to MMG

Hemmerling TM. Can J Anesth 54;58-72, 2007.

Modified Cuff Technique

• Integrated into BP cuff

• Stimulates brachial plexus and integrated sensors quantifies pressure changes of the cuff

Monitoring Sites

• Diaphragm

• Hand (AP, ADM, FDI)

• Face (CS, OO)

• Foot (FHB)

The Diaphragm

Sheiner LB, et al. Clin Pharmacol Ther. 1979 Mar;25(3):358-71

Plasma

Diaphragm

Adductor pollicis

Diaphragm Adductor pollicis

Diaphragm

Adductor

pollicis

The Hand

Renew JR, et al. Anesth Analg. 2021 May 1;132(5):1421-1428.

Bowdle A, et al. Anaesthesia. 2020 Feb;75(2):187-195

Patterns of Neurostimulation

• Single Twitch

• Train-of-four

• Double burst stimulation

• Post-tetanic count

Train of Four

Naguib M, et al. Anaesthesia. 2017 Jan;72 Suppl 1:16-37

Post-Tetanic Count

Naguib M, Brull SJ, Johnson KB. 2017 Jan;72 Suppl 1:16-37.

Dhonneur G, et al. Br J Anaesth. 2007 Sep;99(3):376-9.

• SGX without monitoring resulted in up to 9.4% of patients with

residual weakness after extubation

• “We found that reversal with sugammadex failed to eliminate the

occurrence of postoperative residual weakness”

Kotake Y, et al. Anesth Analg. 2013 Aug;117(2):345-51.

NMBA Antagonism

Monitoring

Optimal NMB Management

Your Practice

AMERICAN

SOCIETY

OF

ANESTHES

IOLOGIST

35

Introducing monitoring into practice

Todd MM, et al. Anesth Analg. 2014 Aug;119(2):323-331.

Weigel WA, et al. Anesthesiology. 2022 Jun 1;136(6):901-915

Path to success

• Local champions

• EMR Integration

• Demonstrate value

• Accountability

• Continued education

• Picking the right monitor(s)

Impact on Sugammadex Usage

• 87% required less than the manufacturer recommendations

• 13% required more

Bowdle TA, et al. Anesthesiology. 2023 Jul 1;139(1):6-15.

Take home points

• Monitoring + reversal = best practice

• Place the monitor pre-induction

• Normalize AMG, try to keep thumb free

• EMG for tucked arms

• PTC for deep blockade

• Muscle groups respond differently to NMB

• Changing the practice is work but monitoring can add value

Questions?

@rossrenew

Renew.j@mayo.edu