STIMPOD NMS410-450X Quantitative NMT Monitor Precision Nerve Locator Ver10 User Manual

Manufacturer Xavant Technology PTY (LTD) Unit 102, The Tannery Industrial Park, 309 Derdepoort Rd Silverton, Pretoria, South Africa, 0184 Tel: +27 (0) 12 743 5959 Fax: +27 (0) 86 547 0026 E-mail: [email protected] Web: www.xavant.com

Legal Representative in the EU Emergo Europe Prinsessegracht 20, 2514 AP The Hague The Netherlands

Caution Federal (US) law restricts this device to sale by or on the order of a physician.

Warnings: • • • •

• •

•

• •

Indications for use: This product is a nerve stimulation device designed to be used by an anaesthetist during • General Anaesthesia, for the purpose of establishing the efficacy of a Neuromuscular Blocking Agent using non-invasive surface electrodes (not supplied) (NMS450X). • Regional Anaesthesia for the purpose of • Nerve mapping using the non-invasive Nerve Mapping Probe (supplied). • Nerve locating using invasive electrodes/needles (not supplied).

Contraindications: • • •

Infection of the puncture site. Known neurological disorders. Severe coagulation disorders.

• • • • •

Cautions: • • • •

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Read the entire User Manual before attempting to use the device. Use of cables or accessories other than those supplied with the STIMPOD may result in serious injury. Maintenance on this device may only be performed by the manufacturer or persons explicitly authorized by the manufacturer. Do not use the STIMPOD in close proximity to equipment that produces strong electromagnetic fields, such as high frequency surgical equipment. The cable leads could act as antennae and dangerous currents could be induced as a result. Do not apply the STIMPOD to patients with implanted electrical devices, such as cardiac pacemakers, without first consulting with an appropriate medical specialist. The device should not be used adjacent to or stacked with other equipment and that if adjacent or stacked use is necessary, the device should be observed to verify normal operation in the configuration in which it will be used. The patient should avoid contact with metallic objects that are grounded, produce an electrical conductive connection with other equipment and/or enable capacitive coupling. The cables should be positioned in such a way that they do not contact either the patient or other cables. Simultaneous connection of a patient to high frequency surgical ME equipment and the STIMPOD may result in burns and possible damage to the stimulator. Operation in close proximity (e.g. 1m) to a shortwave or microwave therapy ME equipment may produce instability in the stimulator output. Application of electrodes near the thorax may increase the risk of cardiac fibrillation. No modification of this equipment is allowed. Do not modify this equipment without authorization of the manufacturer. If this equipment is modified, appropriate inspection and testing must be conducted to ensure continued safe use of the equipment.

Prior to changing the batteries be sure to switch off the device and remove all the cables. Remove elements which may adversely affect the connection between the electrodes and the skin, e.g., dirt, hair, oil. Ensure that ECG electrodes are not damaged or dried out. Large current densities associated with failing ECG electrodes may cause superficial burns.

•

• • • • • •

•

The Stimpod is designed to be compatible with a standard ECG electrode, however, for high currents the use of a dedicated NMT electrode such as the Xavant XT45008 is recommended. Electrodes that have current densities exceeding 2mA/cm2 may require special attention of the operator. This product must be stored at 0 – 50°C. This product must be transported in the carry case provided. This product and all the accessories have been certified latex free. Inspect all parts for any damage or manipulation. Never use any damaged or manipulated part! If an electrically conductive surface of the Stimpod device or its cables are exposed, such electrically conductive surface may shock a person handling it. Do not use such a device or accessory, please contact the manufacturer for repair. The refractory period delay is set at a default value to prevent the user from repeating stimulation while the nerve synapse is recovering from effects of the previous stimulation. A refractory period of less than 12 seconds in TOF mode is not advisable as measurements might not represent the effect of blocking agents on the neuromuscular junction.

STIMPOD (NMS 410/450X) conforms to the following standards: • • •

IEC 60601-1, IEC 60601-2-10 IEC 60601-1-2: CISPR 11 Group1 class A; IEC 61000-4-2; IEC 61000-4-3 ISO 13485, Directive 93-42-EEC

Application Specification: • • • •

The patient population includes patients of all ages, weight and nationality. Patient health and state is described in contraindications, warnings and cautions. The user must be a medical professional with knowledge of anatomy. The use environment requirements of the device such as the medical practice and operating room is described in the guidance and manufacturers declaration. The device can be used on any part of the body except for limitation described in warnings and cautions or identified in section 3 for the NMT mode.

Warranty: • • •

The Stimpod (device only) carries a 24 Month Warranty against defects, provided that the device was used in accordance with the operating instructions. The cables included in the Stimpod Kit carry a 6 Month Warranty against defects, provided that they were used in accordance with the operating instructions. The Stimpod enclosure should not be opened under any circumstances. Opening the unit will void the warranty.

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Guidance and manufacturers declaration – electromagnetic emissions– for all equipment and systems The STIMPOD NMS 410/450X is intended for use in electromagnetic environment specified below. The customer or user of the STIMPOD NMS 410/450X should assure that it is used in such an environment Emission Test

Compliance

Electromagnetic Environment – Guidance

RF Emissions CISPR 11

Group 2 – Class A

The STIMPOD NMS 410/450X must emit electromagnetic energy in order to perform its intended function. Nearby electronic equipment may be affected. The STIMPOD NMS 410/450X is suitable for use in all establishments, other than domestic establishments and may be used in domestic establishments and those directly connected to the public low voltage power supply network that supplies buildings used for domestic purposes, provided the following warning is heeded: WARNING: This equipment/system is intended to be used by healthcare professional only. This equipment/system may cause radio interference or disrupt the operation of nearby equipment. It may be necessary to take mitigation measures, such as reorienting or re-locating the STIMPOD NMS 410/450X or shielding the location

Guidance and manufacturers declaration – electromagnetic immunity- for all equipment and systems The STIMPOD NMS 410/450X is intended for use in the electromagnetic environment specified below. The customer or the user of the STIMPOD NMS 410/450X should assure that it is used in such an environment Immunity Test

IEC 60601 test level

Compliance level

Electromagnetic environment - guidance

Electrostatic discharge (ESD) IEC 61000-4-2

± 6 kV contact ± 15 kV air

± 6 kV contact ± 15 kV Air

Floors should be wood, concrete or ceramic tile. If the floors are covered with synthetic material, the relative humidity should be at least 30%

Power frequency (50/60 Hz) magnetic field IEC 61000-4-8

30 A/m

50 Hz 30 A/m (Effective)

Power frequency magnetic fields should be at levels characteristic of a typical location in a typical commercial or hospital environment.

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Guidance and manufacturer’s declaration – electromagnetic immunity The STIMPOD NMS410/NMS450X is intended for use in the electromagnetic environment specified below. The customer or the user of the STIMPOD NMS 410/450X should assure that it is used in such an environment. Immunity test

IEC 60601 test level

Compliance level

Electromagnetic environment – guidance Portable and mobile RF communications equipment should be used no closer to any part of the STIMPOD NMS 410/450X, including cables, than the recommended separation distance calculated from the equation applicable to the frequency of the transmitter. Recommended separation distance

Conducted RF IEC 61000-4-6

Radiated RF IEC 61000-4-3

3V at 0.15 - 80MHz and 6V at ISM Frequency. Home Healthcare: 3V at 0.15-80MHz, and 6V at ISM and Radio Amateur Frequency.

3V at 0.15 - 80MHz and 6V at ISM Frequency. Home Healthcare: 3V at 0.15-80MHz, and 6V at ISM and Radio Amateur Frequency.

3 V/m (10V/m Home Healthcare) at 80-2,700MHz, AM Modulation. And 9-28V/m at 385-6000MHz, Pulse Mode and other Modulation (upon Risk Analysis).

3 V/m (10V/m Home Healthcare) at d = 1,2 80 MHz to 800 MHz 80-2,700MHz, AM Modulation. And 9-28V/m at 385-6000MHz, Pulse d = 2,3 800 MHz to 2,5 GHz Mode and other Modulation (upon Risk Analysis). where P is the maximum output power rating of the transmitter in watts (W) according to the transmitter manufacturer and d is the recommended separation distance in metres (m). Field strengths from fixed RF transmitters, as determined by an electromagnetic site survey,a should be less than the compliance level in each frequency range. Interference may occur in the vicinity of equipment marked with the following symbol:

NOTE 1 NOTE 2 a

At 80 MHz and 800 MHz, the higher frequency range applies. These guidelines may not apply in all situations. Electromagnetic propagation is affected by absorption and reflection from structures, objects and people.

Field strengths from fixed transmitters, such as base stations for radio (cellular/cordless) telephones and land mobile radios, amateur radio, AM and FM radio broadcast and TV broadcast cannot be predicted theoretically with accuracy. To assess the electromagnetic environment due to fixed RF transmitters, an electromagnetic site survey should be considered. If the measured field strength in the location in which the STIMPOD NMS 410/450X is used exceeds the applicable RF compliance level above, the STIMPOD NMS 410/450X should be observed to verify normal operation. If abnormal performance is observed, additional measures may be necessary, such as re-orienting or relocating the STIMPOD NMS 410/450X. 5

Recommended separation distances between portable and mobile RF communications equipment and the STIMPOD NMS410/450X The STIMPOD NMS 410/450X is intended for use in an electromagnetic environment in which radiated RF disturbances are controlled. The customer or the user of the STIMPOD NMS 410/450X can help prevent electromagnetic interference by maintaining a minimum distance between portable and mobile RF communications equipment (transmitters) and the STIMPOD NMS 410/450X as recommended below, according to the maximum output power of the communications equipment. Rated maximum output power W

150 kHz to 80 MHz

Separation distance according to frequency of transmitter m 80 MHz to 800 MHz

Not applicable 0,01 0,1 1 10 100

-

d = 1,2 0,12 0,38 1,2 3,8 12

800 MHz to 2,5 GHz d = 2,3

0,23 0,73 2,3 7,3 23

For transmitters rated at a maximum output power not listed above, the recommended separation distance d in metres (m) can be estimated using the equation applicable to the frequency of the transmitter, where P is the maximum output power rating of the transmitter in watts (W) according to the transmitter manufacturer. NOTE 1 NOTE 2

At 80 MHz and 800 MHz, the separation distance for the higher frequency range applies. These guidelines may not apply in all situations. Electromagnetic propagation is affected by absorption and reflection from structures, objects and people.

Guidance and manufacturers declaration – electromagnetic immunity – for equipment and systems that are non- life supporting The STIMPOD NMS 410/450X is intended for use in the electromagnetic environment specified below. The customer or the user of the STIMPOD NMS 410/450X should assure that it is used in such an environment Immunity Test

IEC 60601 test level

Radiated immunity 80MHz - 2.5GHz

80MHz – 1GHz @ 3V/m & 10V/m 80MHz – 1GHz @ 3V/m & 10V/m 1GHz – 2.5GHz @ 10V/m 1GHz – 2.5GHz @ 10V/m

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Compliance level

Electromagnetic environment - guidance Portable and mobile RF communications equipment can affect MEDICAL ELECTRICAL EQUIPMENT and should be used no closer to any part of the equipment, including cables, than the recommended separation distance.

Contents 1.

Getting to know the STIMPOD (NMS 410/450X)

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1.1) 1.2) 1.3) 1.4) 1.5) 1.6) 1.7) 1.8)

Device Description Accessories Device Layout Screen Layout Warning Screens Open Circuit Detection Auto Shutdown Symbols

8 9 10 11 12 14 14 14

2.

Nerve Locating/Mapping Mode (NMS 410/450X)

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2.1a) 2.1b) 2.2) 2.3) 2.4)

Adjusting the Current in LOC mode Adjusting the Current in MAP mode Adjusting the Pulse Width Proximity Indicator Adjusting the Twitch Frequency

16 17 18 18 18

3.

Neuromuscular Transmission (NMT) Monitoring Mode (NMS 450X)

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3.1) 3.2) 3.3)

Adjusting the Current Adjusting Stimulation Mode Adjusting the Twitch/ Tetanus Frequency

21 21 21

3.4) 3.5) 3.6) 3.7) 3.8) 3.9) 3.10)

Train of Four Mode (TOF) Double Burst Mode (DB) Post Tetanic Count Mode (PTC) Supra Maximal Current Mode (SMC) Auto Mode Twitch Mode Tetanus Mode

22 22 23 23 24 25 25

4.

Setting up Device Defaults

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4.1) 4.2) 4.3) 4.4)

Setup Menu User Settings NMT Settings Locate Settings

27 27 28 29

5.

Technical Notes

31

5.1) 5.2) 5.3)

Performance Testing Specifications Cleaning and Disinfecting STIMPOD

31 34 34

Products & Accessories

35

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1

Getting to Know the STIMPOD (NMS 410/450)

1.1) Device Description The STIMPOD NMS 450X is quantitative Neuromuscular Transmission (NMT) Monitor which provides real-time quantitative feedback utilizing tri-axial accelerometry. The Stimpod NMS 410 as well as Stimpod NMS 450X is also a precision nerve locating tool used for localizing specific neural pathways. Localization of nerves by electrical stimulation involves connecting the nerve stimulator to a conducting needle through which local anaesthetics can be injected. The distance of the needle (cathode) from the nerve can be estimated by establishing the minimum threshold current required, to facilitate a neuromuscular response. CAUTION: This device should only be used by a qualified physician with appropriate knowledge in anaesthesia. The sale or purchase of the device is restricted to licensed medical practitioners, as governed by the law of the country/state in which he/she practices, or where the device is to be used.

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1.2) Accessories WARNING: Use of cables or other accessories other than those supplied with the STIMPOD may result in serious injury. NOTE: Electrodes and Nerve Locating needles are not included in this package. CAUTION: A sterile wipe should be applied to the Nerve Mapping Probe prior to use. Nerve Mapping/ Nerve Locating Cable (XT-41014): • This cable is used to activate the Nerve Mapping/ Nerve Locating mode on the STIMPOD. • The red (anode) connector is designed to clip on to a standard ECG electrode. • The ergonomically designed cutaneous Nerve Mapping Probe presents the user with a simple and reliable Nerve Mapping solution. • The 2mm needle connector will accommodate various makes of needles.

NMT Monitoring Cable (NMS 450X) (XT-45025): • This cable is used to activate the NMT mode on the STIMPOD. • The red (anode) and black (cathode) connectors are designed to clip onto the Xavant NMT electrode (XT-45008) or onto a standard ECG electrode. • The accelerometer is designed to attach to the contracted appendage (in the case of the ulnar nerve, this will be the thumb).

NMT Electrode (XT-45008): • The colour coded connections indicate the polarity for the NMT cable connections • The larger surface area of the red (anode) electrode reduces the current density of the anode and prevents hyperpolarization • The proprietary gel and gel interface was specifically designed for transmission of large currents.

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1.3) Device Layout

2

3

5

Enter / Frequency Button Press to toggle between Frequencies. Press to Enter in setup menu. Menu / Pulse Width Button NMS 410/450X (LOC/MAP Mode) Press to toggle between Pulse Widths. Press and hold to access Setup Menu. NMS 450X (NMT Mode) Press to toggle between Stimulation Modes. Stimulating LED indicator Flashing Green: Stimulus delivered. Flashing Red: Open Circuit.

Display

The Wheel Adjust current in the main operating mode. Navigate the Setup Menus.

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On / Off Button Press to switch unit on / off.

10

30mA Aut o

NM T

30.21mA 00:15 T O F

Minima l

2 u

3 4

Pause Button 5 NMS 410/450X (LOC/MAP Mode) Press to Stop / Start Stimulation. 6 NMS 450X (NMT Mode) Press and release to elicit a single stimulation. Press and hold to activate a repeated stimulation. 7

6

Multi Functional Clip

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Cable Connector Insert the combined Nerve Mapping / Locating Cable or the NMT cable to activate the relevant 1 mode.

men

1

NMS 450X

Battery Compartment Cover

1.4) Screen Layout Linear mode Non-Linear mode

6 Current Mode Nerve locating mode Nerve mapping mode NMT mode (NMS450X)

1

Data Cable 2

7 Speaker Volume 8 Battery Status

Current Setting 3 Adjust using wheel

9 Average current of actual stimulus 10 Warning: Notifies the user of a discrepancy

between current setting and average current of actual stimulus. 11 Diagnostic or Warning screens 12 Stimulating Frequency Setting Adjust using Enter / Hz width button

Facial Mode 4 Pulse Width Setting 5 Adjust using Menu / Pulse width button

13 men

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Diagnostic Screen NMS 410/450X (LOC / MAP Mode) • Indication of current setting

NMT Mode (NMS450X) Stimulation mode TOF, DB, PTC, TET, TWI, SMC and Auto

Diagnostic Screen NMS 450X (NMT Mode) • Real-time feedback of relative contraction strength measured with the accelerometer • Countdown timer for repeat mode

• Proximity indicator arrow • Calculated Charge Setting • Average charge of actual stimulus

• 0 mA

• Graph indicating shape of actual current stimulus

NMS 450X

• Calculated percentage in TOF and DB mode • Twitch Count in PTC and TOF if less than 4 contractions were identified

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1.5) Warning Screens

Insert Cable

Insert Cable: This is the first prompt which the user will encounter as the unit is switched on, and signals that the unit is waiting for the cable to be inserted.

Cable Not Recognised

Cable not recognised: This warning informs the user that the inserted cable is not compatible with the NMS 410/450X.

Pause

Pause: This warning informs the user that the PAUSE button was pressed. The STIMPOD will pause all its activities and wait for the PAUSE button to be pressed again.

Replace Batteries

Replace Batteries: This warning informs the user that the batteries are depleted beyond an acceptable level. Continuing to operate the device thus will make it unreliable. To prevent this the STIMPOD flashes this warning for 4 seconds before switching off.

Open Circuit Detected

Open Circuit Detected: This warning informs the user that the two electrodes (i.e. ECG electrode and needle or mapping device) do not form a closed circuit. This warning will be accompanied by a red flashing LED, every time the unit attempts to stimulate.

Refractory Delay Active

Refractory Delay Active: Once a TOF, DB, or PTC stimulation is performed, the refractory period timer is initiated. During the countdown time it will not be possible to perform another stimulation. If another stimulation is attempted, this warning screen will appear.

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Press Enter To Confirm

Current Adjustment in NMT Mode: When attempting to adjust the current while in NMT mode the device will show this message, requesting the user to confirm the adjustment of the current.

Stimulation In Progress

Stimulation in Progress: Warning shown when the play button is pressed during stimulation.

EMI Warning

EMI Warning: Warning shown when a high level of electromagnetic interference is detected.

Component Error: The STIMPOD has detected a component failure. Please send the device back to the manufacturer for repair!

Incorrect Electrode Placement

Incorrect/Check electrode placement: Warning shown when SMC is unable to find a supramaximal current value.

No Accelerometer Data Received

No Accelerometer data received: Warning shown when the accelerometer didn’t respond.

Stimulation aborted

Stimulation aborted: This warning is shown when: • SMC: measured current is more than 10% less or more than the set current. • NMT: Stimulation is interrupted by user input.

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1.6) Open Circuit Detection

1.8) Symbols

The Stimpod performs impedance measurements at regular intervals to detect whether the connection between the STIMPOD and the patient comprises a closed circuit. Closed Circuit Detected: • Stimulation will take place. • Stimulating sound will be heard (Single or multiple beeps depending on proximity indicator setting. Sound pitch will follow the current intensity). • The LED stimulus indicator will pulse green with every successful stimulus attempt. • The diagnostic screen will provide active feedback on every pulse delivered.

Manufacturer

Manufacturing Date (Year)

Caution

Separate collection for electrical and electronic equipment (Applicable to EU community only)

Serial Number

Representative in the EU

Catalogue Number

Prescription use only

Open Circuit Detected

Open Circuit Detected: • No stimulation will take place. • No stimulating sound will be heard. • The LED stimulus indicator will pulse red with every unsuccessful stimulus attempt. • A warning screen will appear in the diagnostics screen indicating that an open circuit was detected.

1.7) Auto Shutdown STIMPOD will shut down after 10 minutes of no user or patient interaction.

90% 90% 10% 10% Type BF Applied Part

Consult instructions for use 14

Non-sterile

Humidity limitation

50°C 50°C 0°C0°C Temperature limit

Nerve Locating/Mapping Mode (NMS 410/450X) Locating mode (LOC) Localisation of nerves by electrical stimulation involves connecting the nerve stimulator to a conducting, locating needle (not supplied) through which local anaesthetics can be administered. This procedures involves subcutaneous stimulation of the motor component of the relevant peripheral nerve, to ‘locate’ the nerve. • •

Select this mode by inserting the Nerve Locating / Mapping cable. The STIMPOD will automatically default to the Nerve Locating current range (0.00 5.00 mA) and display the ‘ LOC ’ indicator.

2

This mode offers the user the means to do nerve mapping and locating without having to switch or unplug cables. When inserting the Nerve Mapping / Locating Cable, the STIMPOD will default to the Nerve Mapping current range (0-5mA). Current will be directed to the Nerve Mapping probe and the STIMPOD will attempt to stimulate. The moment that the needle penetrates the skin the cable will sense it and inform the STIMPOD. The stimpod will switch to Nerve locating mode. If contact between the needle and patient is broken, and the nerve mapping probe touches the patient, STIMPOD will switch back to the nerve mapping mode and start monitoring the needle - patient connection again. Whenever the nerve mapping probe and the nerve locating needle simultaneously make contact with the patient the needle will have first priority.

Mapping Mode (MAP) •

This mode is selected when the Nerve Mapping / Locating cable is inserted.

Percutaneous nerve mapping enables the anaesthesiologist to map out a particular superficial nerve prior to nerve location with the needle. This is accomplished by stimulating the motor component of the relevant peripheral nerve percutaneously with the nerve mapping probe. This technique ensures a higher success rate for directing the needle to the correct nerve.

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When using the Nerve Locating / Mapping Cable 3 Warning: Notifies the user of a discrepancy between current setting and average current of actual stimulus. 4 If sound is enabled: STIMPOD will beep every time that a stimulus was delivered. The pitch of the sound will follow the current intensity level. 5 Average current of actual stimulus

Current Setting 1 Adjust using wheel

6 Proximity Indicator 7 Stimulating Frequency Setting Adjust using Enter / Hz width button

Pulse Width Setting 2 Adjust using Menu / Pulse width button

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2.1a) Adjusting the Current in LOC mode 1

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0.6 - 2.0mA Default 0.2mA 2.0 - 5.0mA Default 0.5mA

Current Mode Options: Linear Mode, Non-Linear Mode Default: Linear

Increments can be adjusted in the Setup Menus

Linear Mode:

Circle the Wheel to adjust current.

The Linear Mode is called linear because one ‘click’ on the Wheel will correspond with one Non-Linear Mode: increment as set in the specific current range. The Linear Mode allows the user to selectNMS 450X individual incrementing options for the three different current ranges. The Non-Linear Mode facilitates the non-linear nature of the current intensity versus the distance from the nerve. This mode allows the user to define 20 adjustment positions in Default Current range: terms of Current (mA) and Pulse Width (ms). If correctly implemented each adjustment 0.00 - 5.00mA adjustable in the following default increments: position should afford the user with a relatively linear progression in terms of the distance 0.0 - 0.6mA Default 0.1mA from needle tip to the nerve. 16

Default Current and Pulse Width Range: As shown in table 1 in section 4.4 circle the Wheel to select the predetermined current and pulse width positions sequentially.

NOTE: Because the 20 definable positions include both current and pulse width settings, pulse width cannot be adjusted independently in this mode. This is indicated on the screen by the fact that pulse width is not highlighted.

When using the Nerve Mapping Probe (NMS 410/450X): 3 Warning: Notifies the user of a discrepancy between current setting and average current of actual stimulus. 4 If sound is enabled: STIMPOD will beep every time that a stimulus was delivered. The pitch of the sound will follow the current intensity level. 5 Average current of actual stimulus

Current Setting 1 Adjust using wheel

6 Proximity Indicator 7 Stimulating Frequency Setting Adjust using Enter / Hz width button

Pulse Width Setting 2 Adjust using Menu / Pulse width button

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2.1b) Adjusting the Current in MAP mode 1

NOTE: The STIMPOD will automatically default to the Nerve Mapping current range (0-20mA) and display the ‘ MAP ’ indicator.

Current Range: 0 - 20mA adjustable in 1mA increments. Circle the Wheel to adjust current.

NMS 450X

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2.2) Adjusting the Pulse Width 2

2.4) Adjusting the Twitch Frequency 7

Options: 0.05ms, 0.1ms, 0.3ms, 0.5ms, 1ms Default: 0.05ms Press Menu/Pulse Width button to toggle between different Pulse Widths.

Options: 1Hz, 2Hz, 5Hz Default: 2Hz Press Enter/Hz button to toggle between different stimulating frequencies.

2.3) Proximity Indicator 6 This is only relevant for Locating Mode The proximity indicator notifies the user that the target charge range has been reached. This function allows the user to set up an upper and lower limit of charge. When contraction is elicited at the set charge, this indicator should indicate to the user that the needle has reached the desired proximity to the nerve. This proximity is indicated both visually and audibly. Visual Indication: • Visually indicated in the diagnostics screen by two arrowheads. • Arrowhead indicating the lower threshold points upwards. • Arrowhead indicating the upper threshold points downwards. • The dotted line representing the selected current will be positioned between the two arrowheads if the target charge range is entered. Audible Indication: • A successful stimulus above the proximity range will make a single beep. • A successful stimulus within the proximity range will make a double beep. • A successful stimulus below the proximity range will make a triple beep.

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Neuromuscular Transmission(NMT) Monitoring Mode (NMS 450X) Monitoring Neuromuscular Blocking Agent involves stimulating a neural pathway which facilitates the contraction of an appendage. Based on the relative strength of contraction which is the result of a stimulus of specific intensity or waveform, it is possible to draw conclusions about the efficacy of an injected Neuromuscular Blocking Agent. •

This mode is selected when the NMT cable is inserted.

Electrode Placement Anatomical stimulation sites are chosen based on • their accessibility during surgery • the ability to observe the neuromuscular response • the nerve should be a suitable distance from the responding muscle to prevent direct muscle stimulation Anatomically ideal stimulation sites Targeted Nerve Ulnar nerve Posterior tibial nerve

Affected Muscle Contracting Appendage adductor pollicis muscle Thumb flexor halluces brevis muscle Big toe

Targeted Nerve Affected Muscle Facial nerve (Zygomatic orbicularis oculi muscle Branch) Facial nerve (Temporal Branch) corrugator supercili muscle

3 Contracting Appendage Eye lid Eye brow

Electrode placement relies on the cathode (black electrode clip) to be as close to the targeted nerve as possible in order to effectively depolarize the nerve. The anode (red electrode clip) should be away from the targeted nerve.

Accelerometer Placement The tri-axial accelerometer should be attached to the contracting appendage of the patient, to measure the strength of the contraction resulting from the applied electrical stimulus. Accelerometer is used in Train-of-Four, Double Burst, Post Tetanic Count, Supra Maximal Current and Auto modes, to facilitate monitoring of the efficacy of the Neuromuscular Blocking Agent. 19

Refractory Period Delay The three modes: TOF, DB and PTC are subject to refractory period delays, providing a safety period which prevents the user from repeating stimulation while the nerve synapse is recovering from the effects of the previous stimulation. Immediately after stimulation in one of these modes, the countdown timer is activated and shown on the screen. If repeat mode is activated, only the repeat timer will be displayed on the screen because the repeat period for the repeat timer will always be larger than the refractory period timer. If an attempt is made to stimulate while the refractory timer is active a warning screen will be displayed reminding the user that the refractory period is active. Default refractory period delays are as follows for the three modes: TOF: 15 seconds DB: 1 minute PTC: 2 minutes

Single Stimulus vs. Repeated Stimulation • • • • •

Start the automatic repeat mode by holding the play/pause button down for longer than 2 seconds. The device will automatically start a countdown according to the ‘repeat timer’ setting as specified in the main menu for each respective mode’s timer. The countdown will be indicated next to the clock symbol shown in the diagnostic screen. Disable the automatic repeat mode by pressing and holding the play/pause button again. The Repeat Timer for each mode can be changed in the menu.

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