Technical SeminarTEC-5500 Series Defibrillator

Contents

Features Board/Unit location and Block Diagram Screens for Maintenance Troubleshooting Case StudyNihon Kohden 2008

FeaturesAC and battery power (Ni-MH) operation 5.7 inch color TFT-LCD Synchronized cardioversion AED (Automated External Defibrillation) 50 mm width thermal array recorder External pacing (TEC-5531) External paddles, internal paddles disposable pads Options: 5 lead-ECG, SpO2, etCO2 or AUX out, TEC-5500: Voice prompt/Sound recording in SD card2/36

Board/Unit Location

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Block Diagram - General

Patient ECG signal Peripheral controls Defibrillation energy path

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Block Diagram - OverallMain key board

CPU board

Mother board

Key board

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Parameters Signal Processing

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ECG Signal ProcessingECG signals are input through either the Electrodes or Paddles. Through ECG connection cordPatient ECG signal from ECG electrodes

LEAD ECG floating circuit

ECG signals from the electrodes are input through the LEAD ECG floating circuit. ECG signals are selected in the ECG MPX as lead signals. The lead signal (Lead I, II, III, aVR, aVL, aVF to V) is selected by the user. This lead information is sent from the Main CPU to the Sub CPU.

ECG MPXSelected Lead ECG signal

The ECG Amplifier circuit consists of the following.i)

Differential amplifiers - This circuit amplifies differential (biological) signals and reduces common mode signals (AC interference)High-cut and Low-cut filter - The frequency response is from 0.05 to 150 Hz for input through ECG connection cable 0.05 to 30 Hz when High-cut filter (System Maintenance screen Configuration) and AC filter are set to ON Notch filter - To check if noise is caused by AC interference Signal generator To generate test and calibration waveforms

ECG Amplifier TC, Reset, AC Filter, Test wave, Cal

ii)

iii)

Analog ECG signals

iv)

SUB CPU

The Sub-CPU receives the signals from the ECG Amplifier. The Sub-CPU converts the analog ECG data to digital data and sends it to Main CPU as parallel data through the Main FPGA. The QRS detection, Heart rate count, VF analysis for AED are performed by the Main CPU.

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ECG Signal ProcessingThrough PaddlePatient ECG signal from Paddle

Paddle ECG floating circuit

ECG signals from the paddles are input through the Paddle ECG floating circuit.

The lead signal in this case is fixed to the paddle lead (Apex to Sternum) . ECG MPXPaddle Lead ECG

The Amplifier circuit consists of the following.i)

ECG Amplifier TC, Reset, AC Filter, Test wave, Caliii) iv) ii)

Differential amplifiers This circuit only amplifies potential difference between two electrode. High-cut and Low-cut filter The frequency response is from 0.5 to 20Hz for input through external paddle Notch filter To check if noise is caused by AC interference Signal generator To generate test and calibration waveforms

Analog ECG signal

SUB CPU

The Sub-CPU receives the signals from the ECG Amplifier. The Sub-CPU converts the analog ECG data to digital data and sends it to Main CPU as parallel data through the Main FPGA. The QRS detection, Heart rate count, VF analysis for AED are performed by the Main CPU.

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SpO2 Signal ProcessingSpO2 signals are input through the SpO2 probes

SpO2SpO2 signal from patient

probe/adapter

The Red and Infrared signals are detected through the detector and are sent to the DSI Interface Unit/DSI/AUX Out Interface unit as serial data

Serial data

DSI Interface Unit /DSI/AUX Out Interface UnitSerial data

Sends the serial data (SpO2 value, PR (Pulse Rate) and pulse waveform data) to the FPGA.

FPGA

Converts the received serial data to parallel data and sends it Main CPU.

MAIN CPU

Displays the SpO2 value, PR and pulse waveform data.

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CO2 Signal ProcessingCO2 signals are input through the CO2 sensorCO2CO2 signal from patient

Sensor kitSerial data

The Infrared signals are detected through the detector and are sent to the DSI Interface Unit/DSI/AUX Out Interface Unit as serial data

DSI Interface Unit /DSI/AUX Out Interface UnitSerial data

Sends the serial data (etCO2 value, PR and CO2 waveform data) to the FPGA.

FPGA

Converts the received serial data to parallel data and sends it to the MAIN CPU.

MAIN CPU

Displays the etCO2 value, PR and CO2 waveform data.

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Status Control ProcessStatus signals are fed back to the Main CPU via the Main input port The status are then output to the LEDs through the Main output port

Legends : Input signals Output signals

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Leads Off DetectorPatient ECG signal from Electrodes

Lead ECGfloating circuit

ECG signals from patient are fed through the ECG electrodes to the Lead ECG floating circuit

Leads off detector

This circuit continuously detects if any ECG leads have come off

Leads Detection status

Main Input port

The ECG leads status are sent to the Main Input port

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Paddle Contact IndicatorPatient ECG signal from Paddle

Paddle ECGfloating circuit

ECG signals from patient are fed through the Paddles electrode to the Lead ECG floating circuit

Paddle contactDetector When both Discharge buttons are not pressed, the paddles electrodes pick up the patients physiological signal. From this picked up signal, Main Input the electrode-to-skin contact resistance can be determined

port to Main CPU

Main Output portPaddle contact status

The paddle contact status is sent from Main Output port to the LED status on the External paddle

LED status onExternal Paddle

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Peripheral Control ProcessPeripherals are controlled from the FPGA. These include LCD unit, Audio and Recorder controls

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LCD control process

Main CPU

Sends the waveform data and measurement data to the FPGA.

FPGA

Converts the data to display data and sends it to the LCD.

RGB output to the LCD unit

LCD Unit

Displays the display data on LCD.

LCD Inverter

Converts the DC power to AC power to light the LCD backlight.

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Audio control processMain CPU Requests the voice prompt or sound to to the FPGA.

FPGA

Sends the sound signal to the Voice CPU.

Voice CPU

Sends the voice data to the Sound Amplifier as an analog signal.

Sound Amplifier

Amplifies the voice signal or sound signal and sends it to the Speaker.

Speaker

Outputs the voice signal or sound signal.

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Recorder control processMain CPU Sends the waveform data or measurement data to the FPGA.

FPGA

Converts the waveform data and measurement data to the recording data and sends to the thermal head. Generates the motor driving signal (pulse) for the Motor Driver.

Motor Driver

Drives the Stepping Motor.

Stepping Motor

Fees the recording paper. A stepping motor rotates by an exactly angle with a pulse from the motor driver IC.

Thermal head

Records the recording data.

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Defibrillation Control Process

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HV Circuit Charging/Discharging

External relay Opens and closes the connection between the Paddle ECG input circuit and pacing output circuit, and the HV charging circuit. When the Charge button is pressed, the set of relay switches closes to the connection between the DC/DC converter and HV capacitor for charging. When the Discharge buttons are pressed simultaneously, the set of relay switches closes the connection between the HV capacitor and Patient

Step-up transformer - DC/DC converter that provides the voltage charge the HV capacitor. This block receives the start charging signal from the Sub CPU, and outputs the control signal to the switching FET that switches on or off the HV stepup transformer

Internal relay Used to disarm the capacitor when a fault is detected, the capacitor is in charged condition for more than 40 seconds (default setting, can be changed in Charge hold time), or when the rotary switch is set to Disarm. In this situation, the internal relay closes the circuit to discharge the stored energy of the HV capacitor

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High Voltage CircuitThe energy charging is controlled by the HV circuit. It has the following functions.1. Generates a high voltage to charge the energy in the high voltage capacitor 2. Controls energy charging and discharging 3. HV Fail Safe Circuit- Monitors the voltage of the HV Capacitor comparing with the selected energy to avoid overcharging. - Attenuates the voltage of the HV Capacitor. - Outputs the voltage reading to the Main CPU via the Main PLD. Main CPU in turn halts the HV process via the HV Fail Safe Circuit.

4. Calculates TTR (Transthoracic Resistance) from integration of discharge current change - The change of magnetic flux in the primary winding induces the voltage in thepickup coil (secondary winding). - The voltage at the secondary winding is integrated. Sub CPU calculates the TTR and delivered energy according to the integrated value.

ActiBiphasic Innovation - TEC-5500

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High-voltage Capacitor

Protection from sudden failure of capacitor by segmentation of dielectrics and thin lead connection of cell capacitors Dielectrics

Thin Lead

Electrode (metal)

4,530 small cells21/36

Damage protection by self cutoff

Screens for Maintenance

Basic ChecksSetup

Report Setup - Defibrillation Report/Event List Report Battery Test HV Capacitor Test Recorder Test Report History (Instrumnt Report) Check Hardware22/36

System Setup

System Maintenance

Battery Test Screen

Press the Reset key to delete the previous battery test history when the battery is replaced.Test result Description Action

Battery OK XXX% (Capacity XXX%:100%, 80% 70%) Battery WEAK XXX% Capacity XXX%: 60%, 50%)

Capacity is enough.

Battery operation is available anytime. When the defibrillator is not used, always do trickle charging. Battery operation is available only when the battery is fully charged. The time to replace the battery is coming soon. It is recommended that the battery be replaced with a new one. Only AC operation is available. Immediately replace the battery with a new one.

Capacity has decreased under 70%.

Replace battery XXX% (Capacity XXX%: 40%, 0%)

Capacity has decreased under 50%.

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TroubleshootingThe following repots are useful for troubleshooting.

Defibrillation report (Setup screen Report Setup Defib) Setting and waveforms when discharge operation is performed. Event list report (Setup screen Report Setup Event List) Instrument operation history Instrument report (System Setup screen Report History Instrument report) Error code, battery test and HV capacitor test result We can know what error occurred and what the operator was doing from the reports.24/36

Case StudyPower on problem

Problem: The defibrillator does not turn on when the Energy/Mode Select control (rotary knob) is set to the position other than the OFF position.

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Power on problem

Cause: When the AC power cord is connected to AC outlet on the wall, if the AC power lamp and battery charge lamp are lit, the power unit is operative. Check if you can hear the click sound by pressing any of the key switches on the front panel. There is the click sound: LCD or LCD inverter is faulty. No click sound: Faulty power circuit on the mother board. Solution: Replace the faulty board or unit.26/36

Battery Test Stops

Problem: Battery test stops. Battery was too hot.

Normal example

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Battery Charge Time-out

Cause: The battery temperature exceeds 60C. When the battery temperature exceeds 60C, the battery test stops and the battery check result appears on the screen. Then, the message appears to prompt you to fully charge the battery by tuning the Energy/Mode select control to OFF position. This is normal operation.

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A512 HV Error

Problem: A512 error is displayed and energy cannot be charged. The sub CPU monitors the output of the HV unit. When the output of HV unit does not match the control signal, this error is displayed. Block diagram Error code

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A512 HV Error

Possible Causes:Connection cable between Biphasic HV unit and HV capacitor. Connection cable between Biphasic HV unit and CPU board. HV capacitor Biphasic HV unit

Solution: Replace any of the above failed parts.

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Energy Discharge Test Failure 1

Problem 1: When discharge test is performed in the paddle holder, the Test fail message appears. Problem 2: When the paddle is placed in the paddle holder, paddle contact LED turns red.

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Energy Discharge Test Failure 1

Cause:Resistance of the resistor in the Test Load Board is changed or the resistor is damaged due to test discharge.

Solution:Replace resistors. Test Load Photo

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Energy Discharge Test Failure 2

Cause: Test electrode plate is rusted. Solution: Clean or replace the plate.

Rusted paddle electrode due to remaining paste

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Out of Paper Error

Problem:The Out of paper message appears even when paper is loaded normally and magazine door is tightly closed.

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Out of Paper Error

Cause: Faulty open/close detection sensor of the paper magazine door

Solution: Replace the micro-switch (448053 AV404461).

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