STIMPOD NMS 410 & 450 User Manual ver 5.0

• The Stimpod is designed to be compatible with a standard ECG electrode, however, for high currents the use of a dedicated NMBA electrode such as the Xavant XT45008 (-NA) 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.

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.

STIMPOD (NMS410/450) 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

ii

Guidance and manufacturers declaration – electromagnetic emissions– for all equipment and systems The STIMPOD NMS410/NMS450 is intended for use in electromagnetic environment specified below. The customer or user of the STIMPOD NMS410/NMS450 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 NMS410/NMS450 must emit electromagnetic energy in order to perform its intended function. Nearby electronic equipment may be affected. The STIMPOD NMS410/NMS450 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 re-orienting or re-locating the STIMPOD NMS410/ NMS450 or shielding the location

Guidance and manufacturers declaration – electromagnetic immunity- for all equipment and systems The STIMPOD NMS410/NMS450 is intended for use in the electromagnetic environment specified below. The customer or the user of the STIMPOD NMS410/NMS450 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 ± 8 kV air

± 6kV contact ± 8kV 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

3 A/m

50 Hz 3 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/NMS450 is intended for use in the electromagnetic environment specified below. The customer or the user of the STIMPOD NMS410/NMS450 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 NMS410/NMS450, 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

3 Vrms 150 kHz to 80 MHz

Not applicable

Radiated RF IEC 61000-4-3

3 V/m 80 MHz to 2,5 GHz

3 V/m

d = 1,2

80 MHz to 800 MHz

d = 2,3

800 MHz to 2,5 GHz

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 NMS410/NMS450 is used exceeds the applicable RF compliance level above, the STIMPOD NMS410/ NMS450 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 NMS410/NMS450.

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Recommended separation distances between portable and mobile RF communications equipment and the STIMPOD NMS410/NMS450 The STIMPOD NMS410/NMS450 is intended for use in an electromagnetic environment in which radiated RF disturbances are controlled. The customer or the user of the STIMPOD NMS410/ NMS450 can help prevent electromagnetic interference by maintaining a minimum distance between portable and mobile RF communications equipment (transmitters) and the STIMPOD NMS410/NMS450 as recommended below, according to the maximum output power of the communications equipment.

Rated maximum output power W

Separation distance according to frequency of transmitter m 150 kHz to 80 MHz

80 MHz to 800 MHz

800 MHz to 2,5 GHz

Not applicable

d = 1,2

d = 2,3

0,01

-

0,12

0,23

0,1

-

0,38

0,73

1

-

1,2

2,3

10

-

3,8

7,3

100

-

12

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 nonlife supporting The STIMPOD NMS410/NMS450 is intended for use in the electromagnetic environment specified below. The customer or the user of the STIMPOD NMS410/NMS450 should assure that it is used in such an environment Immunity Test

IEC 60601 test level

Compliance level

Electromagnetic environment - guidance

Radiated immunity 80MHz - 2.5GHz

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

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

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.

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Contents

Page

4.6) Train of Four Mode (TOF) 4.7) Double Burst Mode (DB) 4.8) Post Tetanic Count Mode (PTC) 4.9) Refractory Period Delay 4.10) Twitch Mode 4.11) Tetanus Mode 4.12) Single Stimulus vs. Repeated Stimulation

12 13 13 13 14 14 14

Page

1.

Getting to know the STIMPOD (NMS 410/450)

1

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 on device battery clip

1 2 3 4 5 6 6 6

2.

Operating Device in Nerve Locating Mode (NMS 410/450)

7

2.1) 2.2) 2.3) 2.4)

Proximity Indicator Adjusting the Current Adjusting the Pulse Width Adjusting the Twitch Frequency

7 8 8 8

3.

Operating Device in Nerve Mapping/Locating Mode (NMS 410/450)

9

3.1) 3.2) 3.3)

Adjusting the Current Adjusting the Pulse Width Adjusting the Twitch Frequency

10 10 10

4.

Operating Device in Neuromuscular Blocking Agent 11 (NMBA) Monitoring Mode (NMS 450) 7. Products & Accessories Electrode Placement 11

4.1) 4.2) 4.3) 4.4) 4.5)

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

5.

Setting up Device Defaults

5.1) Languages 5.2) Current Mode 5.3) Pulse Width Options 5.4) Stimulating Frequency 5.5) Repeat Timer TOF, DB, PTC (NMS450) 5.6) Refractory Period Timer TOF, DB, PTC (NMS450) 5.7) Proximity Indicator 5.8) Speaker Volume 5.9) Backlight 5.10) User Information

11 12 12 12

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15 15 16 18 18 18 19 19 20 20 20

6.

Technical Notes

21

6.1) 6.2) 6.3)

Performance Testing Specifications Cleaning and Disinfecting STIMPOD

21 23 23

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1) Getting to know the STIMPOD (NMS 410/450) 1.1)

Device Description

The STIMPOD (NMS 410/450) is 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. The STIMPOD (NMS 450) includes Neuromuscular Blocking Agent Monitoring functionality with real-time feedback achieved by tri-axial accelerometry. CAUTION: This device should only be used by a qualified physician with appropriate knowledge in anaesthesia. CAUTION: 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.

1

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 Locating Cable: • This cable is used to activate the Nerve Locating mode on the STIMPOD. • The red (anode) connector is designed to clip on to a standard ECG electrode. • The 2mm needle connector will accommodate various makes of needles.

Nerve Mapping/ Nerve Locating Cable: • 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.

NMBA Monitoring Cable (NMS450): • This cable is used to activate the NMBA mode on the STIMPOD. • The red (anode) and black (cathode) connectors are designed to clip onto the Xavant NMBA electrode (XT45008) (-NA) 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).

Carry Case

Batteries: • This unit uses 4 x AAA penlight batteries. • Lithium batteries are recommended. • When the battery is depleted the unit will prompt the user to replace the battery and switch off. • Switch device off and remove all cables before replacing battery. • Remove battery if the device is not to be used for an extended period of time, to prevent leakage.

WARNING: If battery acid has leaked into the device essential circuitry may have been compromised. In the event of leakage the device must be returned to its manufacturer for safety checks and possible repairs. 2

1.3)

Device Layout

Cable Connector • Insert the Nerve Locating Cable, the combined Nerve Mapping / Locating Cable or the NMBA cable to activate the relevant mode.

Display

Multi Functional Clip

Enter / Frequency Button • Press to toggle between Frequencies. • Press to Enter in setup menu.

Menu / Pulse Width Button NMS410/450 (LOC/MAP Mode) • Press to toggle between Pulse Widths. • Press and hold to access Setup Menu. NMS 450 (NMBA Mode) • Press to toggle between Stimulation Modes.

Stimulating LED indicator • Flashing Green: Stimulus delivered. • Flashing Red: Open Circuit.

Pause Button NMS 410/450 (LOC/MAP Mode) • Press to Stop / Start Stimulation. NMS 450 (NMBA Mode) • Press and release to elicit a single stimulation. • Press and hold to activate a repeated stimulation.

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

Battery Compartment Cover

On / Off Button • Press to switch unit on / off. 3

1.4)

Screen Layout

Indicators Nerve locating mode

Nerve mapping mode NMBA mode (NMS450)

Non-Linear mode Linear mode

Speaker Volume

Battery Status

Warning

Main Screen

Notifies the user of a discrepancy between current setting and average current of actual stimulus.

• Current Setting Adjust using Wheel. • Diagnostic or Warning Screen

• Average current of actual stimulus

• Pulse Width Setting Adjust using Menu / Pulse Width button.

Warning Screens

• NMBA Mode (NMS 450) Stimulation Mode TOF, DB, PTC, TET, TWI.

• Stimulating Frequency Setting Adjust using Enter / Hz button.

Explained on Page 5.

Diagnostic Screen NMS 450 (NMBA Mode)

Diagnostic Screen NMS 410 / 450 (LOC / MAP Mode)

• Countdown timer • Real-time feedback of for repeat mode relative contraction strength measured with the accelerometer

• Calculated • Proximity indicator arrow Charge Setting • Indication of current setting • 0 mA • Graph indicating shape of actual current stimulus

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

• Average charge of actual stimulus 4

1.5)

Warning Screens 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.

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.

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

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: 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.

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

Refractory Delay Active

Press Enter To Confirm

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.

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

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1.6)

Open Circuit Detection

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:

Open 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.

• 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 shutdown after 10 minutes of no user or patient interaction.

1.8)

Symbols on device battery clip

Manufacturer

Type BF Applied Part

Caution

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

Consult instructions for use

6

Manufacturing Date (Year)

Serial Number

Representative in the EU

2) Operating Device in Nerve Locating Mode (NMS 410/450) 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 cable. • The STIMPOD will automatically default to the Nerve Locating current range (0.00 - 5.00 mA) and display the ‘ LOC ’ indicator.

2.1)

Proximity Indicator

The proximity indicator is activated when the combination of current and pulse width settings result in a charge which is within the range as selected in the SETUP MENU, section 5.7.

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. 77

2.2)

Adjusting the Current

Current Mode Options:

Sound:

Options in the Setup Menu: Linear Mode, Non-Linear Mode Default: Linear

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.

Linear Mode:

Non-Linear Mode:

The Linear Mode is called linear because one ‘click’ on the Wheel will correspond with one increment as set in the specific current range. The Linear Mode allows the user to select 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 terms of Current (mA) and Pulse Width (ms). If correctly implemented each adjustment position should afford the user with a relatively linear progression in terms of the distance from needle tip to the nerve.

Default Current range: 0.00 - 5.00mA adjustable in the following default increments: 0.0 - 0.6mA Default 0.1mA 0.6 - 2.0mA Default 0.2mA 2.0 - 5.0mA Default 0.5mA

Default Current and Pulse Width Range: As shown in table 5.1 in section 5.2 circle the Wheel to select the predetermined current and pulse width positions sequentially.

Increments can be adjusted in the Setup Menus (refer to 5.2)

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.

Circle the Wheel to adjust current. Warning Notifies the user of a discrepancy between current setting and average current of actual stimulus. Average of actual current delivered.

2.3)

Adjusting the Pulse Width

2.4)

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

Adjusting the Twitch Frequency

Options in the Setup Menu: 1Hz, 2Hz, 5Hz Default: 2Hz Press Enter/Hz button to toggle between different stimulating frequencies. 8

3) Operating Device in Nerve Mapping/Locating Mode (NMS 410/450) 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. 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 (0-20mA). 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 and behave as described in chapter 2. 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. • This mode is selected when the Nerve Mapping / Locating cable is inserted. 99

When using the Nerve Mapping Probe (NMS 410/450): Sound:

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

3.1)

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.

Adjusting the Current Average of actual current delivered.

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

3.2)

Warning Notifies the user of a discrepancy between current setting and average current of actual stimulus.

Adjusting the Pulse Width

3.3)

Options in the Setup Menu: 0.05ms, 0.1ms, 0.3ms, 0.5ms, 1ms Default: 0.1ms, 0.3ms Press Menu/Pulse Width button to toggle between different pulse widths.

Adjusting the Twitch Frequency

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

When using the Nerve Locating Needle: • Connect the needle to the Nerve Mapping/Locating cable. The moment that the needle penetrates the skin the cable will communicate this to the STIMPOD, switch to nerve locating mode, and switch the stimulation to the needle. The current in locating mode will default to 0.00mA. • The STIMPOD will now function exactly as described in Chapter 2. • 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. Mapping mode will default back to 0mA. • Whenever the nerve mapping probe and the nerve locating needle simultaneously make contact with the patient the needle will have first priority.

10

4) Operating Device in Neuromuscular Blocking Agent Monitoring Mode (NMS 450) Monitoring Neuromuscular Blocking Agents 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 NMBA cable is inserted.

4.1)

4.2)

Electrode Placement

4.1.1) 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

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. The accelerometer is only used in the Train-of-Four, Double Burst and Post Tetanic Count Modes, to facilitate monitoring of the efficacy of the Neuromuscular Blocking Agent.

4.1.2) Anatomically ideal stimulation sites: Targeted Nerve

Affected Muscle

Contracting Appendage

Ulnar nerve

adductor pollicis muscle

Thumb

Posterior tibial nerve

flexor halluces brevis muscle

Big toe

Facial nerve (Zygomatic Branch)

orbicularis oculi muscle

Eye lid

Facial nerve (Temporal Branch)

corrugator supercili muscle

Eye brow

Accelerometer Placement

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. 11 11

When using the Neuromuscular Blocking Agent Monitoring Mode (NMS 450): 4.3)

Adjusting the Current

Sound: 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.

When attempting to adjust the current in NMBA mode the Stimpod will show a message requesting to confirm the adjustment of current. When this message appears, press the ‘enter’ button. This will cause the current intensity to flash on and off, which means that the current can now be adjusted.

Average of actual current delivered. Warning Notifies the user of a discrepancy between current setting and average current of actual stimulus.

If current has not been adjusted for more than 2 seconds, the current will be set. Default Current range: 0 - 80 mA adjustable in 5mA increments. Circle the Wheel to adjust current.

4.4)

4.6)

Adjusting Stimulation Mode

The TOF stimulation comprises four, square waves with a pulse width of 200 microseconds, 500 milliseconds apart.

Options: TOF, DB, PTC, TET, TWI Default: TOF Press Menu/Mode button to toggle between different Stimulation Modes.

4.5)

Train of Four Mode (TOF)

Selecting TOF Mode: • Insert the NMBA cable with the red and black electrode clips as well as the tri-axial accelerometer. • Press the ‘Mode’ button until ‘TOF’ is shown on the display.

Adjusting Twitch/Tetanus Frequency

Twitch Mode:

Real-time Accelerometry: • The relative contraction strength caused by each stimulus is indicated graphically in the diagnostic screen as shown in the picture. • In the case that all four contractions could be measured, the percentage of measured contraction strength of the fourth stimulus compared to the first stimulus will be displayed in the diagnostic screen. • If less than four contractions were measurable, the number of contractions that could be identified by the accelerometer will be displayed, e.g., 2/4.

Options in the Setup Menu (Stimulating Frequency): 1Hz, 2Hz, 5Hz Default: 2 Hz Press Enter/Hz button to toggle between different stimulation frequencies.

Tetanus Mode: Options: 50Hz, 100Hz Default: 50Hz Press Enter/Hz button to toggle between different stimulating frequencies. 12

4.7)

Double Burst Mode (DB)

4.8)

Post Tetanic Count (PTC)

The DB stimulation comprises a burst of three square waves of 200 microseconds pulse width, 20 milliseconds apart, followed by another burst of three square waves, 750 milliseconds later.

Defaults: Tetanus: 50Hz for 5 seconds Delay: 3 seconds Twitch: 20 twitches at 1Hz

Selecting DB Mode: • Insert the NMBA cable with the red and black electrode clips as well as the tri-axial accelerometer. • Press the ‘Mode’ button until ‘DB’ is shown on the display.

The PTC stimulation comprises a tetanus stimulation followed by a delay and a number of twitches. (Default settings are as shown above) Selecting PTC Mode: • Insert the NMBA cable with the red and black electrode clips as well as the tri-axial accelerometer. • Press the ‘Mode’ button until ‘PTC’ is shown on the display.

Real-time Accelerometry: • The relative contraction strength caused by each stimulus is indicated graphically in the diagnostic screen as shown in the picture. • The percentage of the measured contraction strength of the second contraction compared to the first contraction will be displayed in the diagnostic screen.

4.9)

Real-time Accelerometry: • Each counted twitch is indicated graphically in the diagnostic screen as shown in the picture. The number of twitches counted are displayed in the diagnostic screen.

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 minute

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4.10) Twitch (TWI)

4.11) Tetanus (TET)

Defaults: Repeat at 2Hz Adjustable:1Hz, 2Hz and 5Hz

Defaults: 50Hz (adjustable to 100Hz) The Tetanus stimulation comprises series of 200 microseconds square wave pulses repeated at a 50Hz or 100Hz repetition rate or frequency.

The Twitch stimulation comprises a 200 microseconds square wave pulse. If the ‘Play/Pause’ button is pressed the twitch will repeat at the selected frequency.

Selecting TET Mode: • Insert the NMBA cable with the red and black electrode clips as well as the tri-axial accelerometer. • Press the ‘Mode’ button until ‘TET’ is shown on the display.

Selecting TWI Mode: • Insert the NMBA cable with the red and black electrode clips as well as the tri-axial accelerometer. • Press the ‘Mode’ button until ‘TWI’ is shown on the display.

Stimulate/Stop: Start stimulation by holding the ‘Play/Pause’ button down. Stop stimulation by releasing the ‘Play/Pause’ button.

Stimulate/Stop: Start stimulation by pressing the ‘Play/Pause’ button. Stop stimulation by pressing the ‘Play/Pause’ button again. Frequency adjustment: Press the ‘Hz’ button to toggle through the frequencies.

4.12) 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 defaults at 2 minutes and can be changed in the menu.

14