mgm’s college of engineering and technology

8/14/2019 Mgms College of Engineering and Technology

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MGMS COLLEGE OF ENGINEERING AND TECHNOLOGY [Pick the date]

INSTRUMENT REPORT

ON

DEFIBRILLATOR

BY

JUNED SIDDIQUE

REMARK: ______________ SIGN. :

__________________

JASLOK HOSPITAL AND RESEARCH CENTRE | [Type the company address]


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HEARTSTART XL DEFIBRILLATOR

INTRODUCTION

A Defibrillator is an instrument used for administering a high energy

shock wave to the heart during fibrillation, to is restore its normal

rhythm. The electric shock is given to the patient through large paddle

shaped electrodes pressed against the skin of the chest.

In cardiac fibrillation, the main problem is that heart muscle fibres are

continuously stimulated by adjacent cells so that there is no

synchronized succession of events that follow the heart action. There

might be atrial fibrillation or ventricular fibrillation.

Atrial fibrillation: The electrical signal in the upper chambers of the

heart is not organized and flowing rhythmically through the heart

muscle. Its a very fast and irregular contraction of the atria. AF occurswhen the electrical signal begins in the different part of the atrium than

the sinoartial node or when the signal is conducted abnormally. When

this happens the electrical signal doesnt travel through the normal

pathways in the atria, but instead may spread throughout the atria in a

fast and disorganized manner ,this causes the walls of the atria to

quiver very fast instead of beating normally.



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As a result atria arent able to pump blood into the ventricle the way

they should.

Waveform of atrial fibrillation

Ventricular fibrillation is a serious cardiac emergency and most

ominous arrhythmia. The uncoordinated movements of ventricular

walls of the heart may result from coronary occlusion, from electric

shock or from abnormalities of body chemistry. Because of this

irregular contraction of muscle fibers, ventricular pumping ceases,

blood is not ejected and there is steep fall of cardiac output. This might

prove fatal and death will occur if adequate steps are not taken

promptly. Therefore a strong, brief electrical current is passed across

the chest to stop ventricular fibrillation.

Fig 4.2 Waveform of ventricular fibrillation



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FEATURES

Reliability and safety

Rugged mechanical design: The Heartstart Xl is built with high impact

plastic which has few openings and incorporate a rugged defibrillationpads connector and battery interface.

Daily automatic self test: The Heartstart XL performs a daily test to ensure

it is ready to use when needed.

Ease of use

Small and light: The biphasic waveform technology used in Heartstart XL

has allowed them to be small and light.

Voice prompts: Heartstart XL provides audible prompts that guide the user

through the device process.

Clear labeling and graphics: The Heartstart XL is designed enable fast

response by the user.

Offers two modes of operation:

1. Automatic External Defibrillation (AED) Mode

2. Manual Mode



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ECG monitoring can be accomplished in either mode using one of 2

methods:

1. ECG from the defib pads.

2. 3-lead ECG using separate monitoring electrodes.

Powered by AC Power and a Rechargeable Sealed Lead Acid (SLA) battery.

Provides non-invasive transcutaneous pacing.

It automatically stores critical events, in its internal memory.

Provides (SpO2) monitoring with a provision to set alarm limits.

PRINCIPLE OF OPERATION

The basic principle underlying applying the shock is that the charge is

stored on capacitor. Energy storage capacitor is charged at relatively slow

rate (in order of seconds) from AC line by means of step-up transformer and

rectified arrangement or from a battery and a DC-to-DC converter

arrangement, the energy stored in the capacitor is then delivered at a

relatively rapid rate (order of milliseconds) to the chest of the patient. For

effective defibrillation some shaping of the discharge current pulse is

adopted. The simplest arrangement involves the discharge of capacitor

energy through the patients own resistance, this results in exponential

discharge typical of an RC circuit. Rectangular and trapezoidal waveforms are

found effective and are employed in defibrillators design for clinical use. The

basic circuit diagram of a defibrillator consists of a variable auto-transformer



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T1 which forms the primary of a high voltage transformer T2.The output

voltage if transformer is rectified by a diode rectifier and is connected to a

vacuum type high voltage change over-switch. In position A, the switch is

connected to one end of an oil-filled or electrolytic capacitor. In this position

capacitor charges to a voltage set by the positioning of the auto- transformer.

When the shock is delivered to the patient, a foot switch or a push button

mounted on the handle of the electrode is operated. The high voltage switch

changes over to position B and the capacitor is discharged across the heart

through the electrodes.

In a defibrillator an enormous amount of voltage (approx. 4000V) is

initially applied to the patient. Although short duration pulses can affect

defibrillation, the high current required impairs the contractility of the

ventricles. This is overcome by inserting a current limiting inductor in series

with patients circuit. The inductor slows down the discharge from the

capacitor by the induced counter voltage, which gives output pulse a

physiologically favorable shape. The shape of the waveform of that appear

across electrodes depends on the value of the capacitor and inductor used inthe circuit.

The different types of waveforms used for defibrillation are:

Monophasic Damped sine Waveform

Biphasic Waveform

Monophasic Damped Sine Waveform

Most of the defibrillators are designed that uses DC types of waveform

known as Monophasic Damped Sine. The Monophasic Truncated

Exponential was used in early AEDs. Monophasic waveforms continue to



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be widely used in hospitals today. They use escalating high levels of

energy delivered in one direction through the patients heart. The

maximum energy setting for Monophasic Damped Sine is 360J.

Monophasic waveform always assumes that patient impedance is 50

ohms.

C

Fig 4.4 Monophasic waveform

Biphasic Waveform

In biphasic waveform energy I delivered in both the directions through

the patients heart that too at low energies. In M4735 HeartStart XL

defibrillator SMART Biphasic waveform technology has changed the way

defibrillation therapy is delivered.

C

T

Biphasic waveform

A clinician using monophasic defibrillator would typically


T


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shock a patient using escalating energy levels (200-300-600J), while using

SMART biphasic defibrillator shock recommended at 150J is given

consistently. As a result, there is a decrease in myocardial dysfunction to the

patient. Unlike the Monophasic Damped Sine Waveform, the SMART Biphasic

waveform measures the patients impedance and adjust the waveform

accordingly prior to the delivery of shock.

The success of defibrillation correlates better with the amount of energy

stored in the capacitor than with the value of the voltage used, hence the

output of the DC defibrillator is calibrated in terms of watt-seconds or joules

as a measure of electrical energy stored in the capacitor.

Energy in watts seconds is equal to one half the capacitance in farads

multiplied by the voltage in volts squared, i.e. E=1/2C(V)2 .

The amount of energy that the defibrillator actually delivers to the patient

is of more relevance. This can be determining factor energy can be

estimated by assuming the value of a load resistance that is placed between

the electrodes and thus simulates the patients resistance.

MODES OF OPERATION

The two modes of operation for defibrillator are:

Automatic External Defibrillation (AED) Mode

Manual Mode



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In AED mode, the defibrillator analyzes the patients ECG and advices the

clinician whether or not to deliver a shock. Voice prompts guide you

through the defibrillation process by providing instructions and patient

information.

Voice prompts reinforced by messages that appear on the display.

Monitoring is available in AED mode through pads, 3-lead ECG monitoring

electrodes or optional 5-lead ECG monitoring electrodes.

The AED algorithm is not designed to handle erratic spike problems

caused by a properly or improperly functioning pacemaker.

An AED is to be used in the presence of a suspected cardiac arrest on

patients of at least 8 years of age that are:

Unresponsive

Not breathing

Pulse less

An AED is not to be used on patients that exhibit one or any combinations of

the following:

Responsiveness

Spontaneous breathing

Palpable pulse



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Overview of Automatic External Defibrillation (AED) Mode


IF THE PATIENT IS

UNRESPONSIVE

BREATHLESS

PULSELESS

ATTACH PADS

ROTATE ENERGY

SELECT KNOB TO AED

MODE

IF INSTRUCTED, PRESS ANALYZE

SHOCK ADVISED NO SHOCK ADVISED


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At completion


Manual Mode

In manual Mode, defibrillator turns control of defibrillation process over to

the user. The user accesses the patients ECG and selects the energy sitting

for the defibrillation if necessary. Monitoring is available in AED mode

through 3-lead ECG monitoring electrodes or optional 5-lead ECG monitoring

electrodes. There are no voice prompts. However, system and momentary

messages provide relevant information throughout the process. It is

important to be attentive to these messages. In manual mode, defibrillator is

always performed through paddles or pads.

Manual mode allows the user to perform synchronized cardio-version and

offers non-invasive pacing(optional).

Synchronized Cardio version:


PRESS SHOCKCHECK PATIENT

NO PULSE

PRESS

PAUSE

VENTI-

LATE

Within a shock series

Of shock

If rhythm monitoring on


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Synchronized Cardio version involves delivering a shock that is

synchronized to the R wave of the ECG. The defibrillator is responsible for

detecting the R wave of the ECG and placing markers on the printed strip and

on the display to indicate the timing of the proposed cardio version shock.

The specific point on the R wave is selected to avoid the heart to enter into

ventricular fibrillation

Non-invasive pacing:

It provides non-invasive transcutaneous pacing by delivering a

monophasic, electrical stimulus to the heart. This stimulus is intended to

cause cardiac depolarization and myocardial contraction. It is used fortreating with symptomatic bradycardia, if performed early. Paced pulses are

delivered through multifunction defibrillator electrode pads, applied to the

patients bare chest. It can deliver paced pulses in either demand mode or

fixed mode. Use demand mode pacing whenever possible. Observing the

patient closely while pacing is very important. In demand mode, the pacer

delivers paced pulses when the patients heart rate is lower than the selected

pacing rate.

FRONT PANEL AND DISPLAY



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Front Panel of Defibrillator

The HeartStart XL Defibrillator has various controls and corresponding soft

keys for the functions to be performed. There are softkeys for using pacer

mode, for printing event summary, increasing and decreasing ECG size and

volume used for voice prompts which guides through defibrillation process

when AED mode is used. The monitor displays various alarms limits, selected

lead and the different elements that appear while using AED mode or Manual

mode.

The front panel consists of defibrillation controls, audiovisual controls,

monitoring controls, print controls and Manual as well as AED mode controls

and display layout when used in AED or Manual mode. There is patient cable

connector, data card and battery input on the front side.

FRONT PANEL DESCRIPTION:



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Defibrillation Control:

It consists of energy select knob and a set of softkeys that perform

the fuction displayed as a label above each button. These controls

assist in both AED and manual mode defibrillation.

Audiovisual Controls:

Adjusts the volume of voice prompts and the QRS beeper.

Adjusts the size of the ECG waveform displayed, printed, and

stored. Processing and simultaneously generously a 1mV calibration

pulse.

Monitoring Controls:

It consists of set of softkeys monitoring functionality. These

functions are displayed in the softkeys label below each button.

Monitoring softkeys also control heart rate and SpO2 alarms, and

selection of the ECG source to monitor.

Print Control:

Print Controls performs the function shown on each button. The print

controls from are:

Prints ECG data, defibrillation events. And marked

events real-time or with a 6 second delay. Press to

start printing; press again to stop printing.


Strip


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Prints the event summary. Printing may be stopped

by pressing the Summary or Strip button.

Inserts a timed stamped annotation in the Event

summary. It may be configured to print an annotated

ECG strip when pressed.

Manual Mode Controls:

It provides access to manual defibrillation and synchronized

cardioversion and optional pacing functionality. Synchronized

cardioversion and pacing controls only function when manual mode is

enabled. It consists of energy select knob and pacing controls, which

are described as follows.

Energy select knob: it is used to enable both manual mode and AED

mode. The AED On position activates AED mode. Manual On enables

Manual mode, synchronized cardioversion and pacing.

Button below the display (far left) that enables

synchronized cardioversion when first pressed in

manual mode; disables synchronized cardioversion

when pressed again.


Summa

ry

Mark


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Activates the pacing functions buttons, allowing to

visualize the buttons below to define pacing rate,

mode, and current output. Also turns off the pacer

function when pressed a second time.

Adjust the pacing rate.

Starts pacing, delivers pacer pulses when first

pressed; stops Pacing when pressed again.

Selects Demand or Fixed Mode for pacing.

Adjusts the current output for pacing.

Display Layout

The elements that are displayed on the screen when AED or manual

mode is selected are almost same except few which are explained

as follows.


Pacer

Mode

Rate

Output

Start/S

top


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AED Mode

Displays shows heart rate and its alarm, the ECG lead which is

selected, oxygen saturation (SpO2) value and its alarm, pleth bar

and pulse rate derived from pulse oximetery, ECG of the patient,

number of shocks delivered to the patient, incident timer shows the

elapsed time since the HeartStart XL was turned on.

The defibrillation softkeys when AED mode is selected (pause,

analyze and shock). User message areas accompany voice prompts

to guide through the defibrillation process. System and Momentary

messages provide status information, offer recommendation andalerts to conditions that require attention. System message remains

on the display until the condition that generated the message no

longer exists. Momentary message is temporary and appears on the

display for a minimum of 3 seconds.

Manual Mode

The information that is displayed is same for manual mode also

except for the defibrillation softkeys. There is display which shows

that synchronization is on or off. The defibrillation softkeys in

manual mode are sync on/off, charge and shock.

REAR PANEL



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Fig 4.7 Rear Panel

Connecting To Power:

Ac power and the M4735A battery power the Heartstart XL.

Printer:

To take printouts of required medical parameters,such as strip prints of

required ECG Lead.

ECG Connector:

To connect 3-5 ECG Lead patient cable



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SpO2 Connector:

To connect SpO2 patient cable

ECG Out(Sync) Jack:

To connect pads and external and internal paddles.

The patient cable connector from ECG Out is used to connect:

External paddles

Pads cable patient used for multifunction defibrillator

pads

AC Power:

The required AC power is 230V.



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BLOCK DIAGRAM OF HEARTSTART XL

DEFIBRILLATOR


CONTROL BOARD

HIGH VOLT

CHARGERPOWER

SUPPLY BATTERY

STATUSHIGH VOLT

CAPACITOR

SWITCHING/ISOLATIO

ECG FRONT END

REAL TIME CLOCK

DATA CARD

BEEPER

ON

/OFF

SHOCK

SHOCK LED

APEX

APEX

STERNUM

STERNUM


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BLOCK DIAGRAM DESCRIPTION

Control Board

The control board holds the main processor and all of the circuitry

required to control the real time functions of the defibrillator. The real

time control provides the signals needed to sample the ECG and voice

data onto data card, send data to display and play the voice prompts

on the speaker, turn on various tones, charge the high voltagecapacitor and deliver the shock to patient. In addition, the processor on

the control board runs all of the data processing for analysis system.


TEMPERATURESENSOR

IR PORT

MICROPHONE

SPEAKER


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Patient Circuit

This circuitry includes all components needed to deliver the

defibrillator waveform to the patient. The large amount of energy

stored in the battery is low voltage that is not effective for defibrillatorshock. In order for the patient to be defined, enough energy for one

shock must be transferred to the high voltage capacitor at a voltage

high enough to make defibrillator waveform effective. This voltage is

maintained on the capacitor until the shock is delivered, ensuring that

the device is ready to deliver a shock of 150J to the patient. When the

shock button is pressed, the HV capacitor is disconnected from the HV

charger circuit and connected to patient throughout the electrode

pads. The switching circuitry then allows the current to flow in onedirection pad to pad through the patient, and then reverses the

direction of flow for a preset period of time. The direction of current

through the patient is based on the measured impedance. It is bi-

directional flow of current that forms the SMART BIPHASIC waveform.

User Interface

The user interface consists of the main LCD display, the on/off button,

the shock button, the connector light, shock button light, the beeper,

and the speaker and status indicator.

In normal operation, text prompts are displayed on main LCD and voice

prompts are provided through the speaker. These prompts guide the

rescuer in the use of the device and give warnings such as low battery,

to call the users attention to certain parts of the device that may need

attention. The connector light blinks when the unit is turned on to

draw attention. the voice prompt and display guides the user in



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connecting the defibrillation pads to the AED and the AED advices a

shock and charges, the shock button light blinks to guide the user to

the shock button and to indicate that it is ready to deliver a shock to

the patient. The beeper is also provided to draw users attention

indicating either that the device is ready for delivering a shock or the

battery is low and needs to be replaced.

Battery

The power source for defibrillator is a 12 V, 2Ah battery pack. The

battery packs are rechargeable.

Power Supply

The power supply is used to convert the battery voltage to various

voltages needed to supply the electronics within the defibrillator.

ECG Front End

The front end amplifies and filters the ECG signal input from electrodes

and feeds this signal into A/D converter the sampling rate for A/D

converter is 200 Hz and this digital data is fed into the control board to

be used by analysis system and stored onto the data card.

Recording



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When the AED is turned on and the pads are applied to the patient, the

AED continuously records the ECG and the event summary onto the

data card if installed. The AED can also record all the audio information

from the event through the microphone. The ECG and audio

information can later be reviewed using event review data

management software.



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APPLICATION

The M4735A HeartStart XL Defibrillator is for use in hospital in

basic life support, advanced cardiac life support or defibrillation.

When operating as a semi-automatic external defibrillator in

AED Mode, it is suitable for use by medical personnel trained in basic

life support for use that includes use of an AED.

When operating as a defibrillator/monitor in Manual Mode, it issuitable for use by healthcare professionals trained in advanced

cardiac life support.



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SAFETY PRECAUTIONS

Use multifunction defibrillator pads prior to their expiration date.

Discard pads after use. Do not reuse it.

Use only 3-wire AC power cords with 3-pronged

grounded plugs.

Avoid touching of multifunction defib pads with each

other .Contact with metal objects may cause electrical arcing andpatient skin burns during defib and may divert current away from the

heart.

During defib air pockets between skin and pads may

cause patient skin burns. To help prevent air pockets, make sure the

pads completely adhere to the skin.

Do not use the equipment in a flammable or oxygen-rich

atmosphere.

Avoid connecting the patient to many devices at once.

Leakage current may exceed.

Do not discharge the defibrillator with the paddles

shorted together.

Electromagnetic compatibility with surrounding device

should be assessed prior to using the defibrillator.



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CLEANING THE UNIT

Cleaning the HeartStart XL

Isopropyl alcohol (70% in water)

Mild soap and water

Chlorine bleach (3% in water)

Compounds such as Lysol (10% in water)

When cleaning be sure to avoid pouring fluids on the device and do

not allow fluid to penetrate the exterior surface of the device.

Cleaning the printer head

If the printout is light then clean the printer head to remove any

build up paper residue.

Cleaning the external and internal paddles

Clean the electrode surface and handle with standard hospital

solution. Do not use enzymatic or ammonia based cleaners. Use

a small , soft brush with cleaning solution to clean any

contamination from electrode surface and edge.



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Cleaning the pads cable

Clean using any of the following:

2% gluteraldehyde solution (such as cidex)

Sodium hypochoride

Cleaning the ECG cable

Wiping with any one of the following may clean the ECG cable

2% gluteraldehyde solution (such as cidex)



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TECHNICAL SPECIFICATIONS

Separate specifications are given for defibrillator, ECG monitoring, SpO2

monitoring, display, printer, battery, etc. they are listed as follows:-

Charge Time:

Less than 3 seconds to 200 Joules with a new, fully charged M3516A SLA

battery pack at 25oC. Less than 15 seconds to 200 Joules when powered

by AC with no battery installed.

Patient Impedance Range:

25 to 180 Ohms.

Manual Output Energy (Delivered):

2, 3, 5, 7, 10, 20, 30, 50, 70, 100, 150,200 Joules.

AED Mode:

AED Energy Profile: Fixed Energy (150 Joules).

AED Shock Series: 1, 2, 3, or 4 shocks per series.

Shock Series Timer: off, 30, 60, 90, 120, 150, 180, or 210 seconds.



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ECG Monitoring:

Heart Rate Display: Digital readout on display from 15 to300bpm,with

an accuracy of 10%.

Heart Rate Alarms: Configurable pairs of low and high heart rate alarm

limits : 30 to 100, 60 to 140, 90 to 160, and 120 to 200 bpm.

Hands Free Defibrillation: Patient Cable Length: 7 ft. (2.13 m).

ECG Cable Length: 12 ft. (3.7 m).

ECG Size: 2.5, 5, 10, 20, 40 mm/mV.

Display:

Size: 115 mm x 86 mm.

Type: EL Electroluminescent.

Resolution: 320 x 240 pixels.

Sweep Speed: 25 mm/s nominal (stationary trace; sweeping erasebar).

Viewing Time: 4 seconds.

Battery:

Type: 2 Ah, 12V, rechargeable, Sealed Lead Acid (SLA).

Dimensions: 61.7 mm (H) x 23.9 mm (W) x 182 mm (D).

Weight: 1.4 lb. (0.65 kg).

Charge Time: Approximately 15 hours total to 100%.

Capacity: >100 minutes ECG monitoring.



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Battery Storage: Should not be stored above 40C for extended

periods

of time.

Thermal Array Printer:

Speed: 25 mm/s with an accuracy of 5%.

Paper Size: 50 mm by 30 m (100 ft.).

Internal Event Summary:

The internal Event Summary stores up to 300 events and up to 50

waveforms.

Temperature:

0 to 55C operating, -20C to 70C storage.

AC Line Powered:

100-240 VAC, 50/60 Hz, .4A max (unit off), 1.5A max (while charging ).

Battery Powered:

12 V Rechargeable, SLA.

Dimensions:

19 cm (H) x 37.6 c cm (W) x 34.6 cm (L).

Weight:



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6kg, including battery and one roll of paper.

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