The document provides information on defibrillators including: 1. Defibrillators deliver an electrical shock to the heart to stop an irregular heartbeat and restore normal rhythm. 2. The history of defibrillation is traced from early experiments in the late 1800s to the development of automatic external defibrillators. 3. Key aspects like energy levels, waveforms, types of defibrillators including manual, automatic, external, internal and implantable devices are described.

1. Presented by,
Athulya.S
Deepika.S.S

2. 2
DEFIBRILLATOR
 ™Defibrillator is a device that
deliver a therapeutic dose of
electrical energy to the affected
heart to force the heart to produce
more normal cardiac rhythm .

3. TO THE PAST……
• In 1899 Prevost and Batelli first introduced
the concept of electrical fibrillation
• In 1933 Hooker, Kouwenhoven and
Langworthy published an account of
successful alternating current (AC)
internal animal defibrillation
• 1950 -Kouwenhoven was able to
defibrillate dogs by applying the
electrodes to the chest wall.
• In 1956 Zoll defibrillated a human subject
in the same manner.

4. CONTD….
In1960s Edmark and Lown et al found
that direct current (DC) or pulse
defibrillators were more effective, the
DC pulse waveform was further
improved.
1970s -Experimental internal and
external devices were designed to
automatically detect ventricular
fibrillation.
1980s -The first automatic internal

5. HEART
 Located between the
lungs in the middle of
chest.
 An average heart pumps
2.4 ounces (70 millilitres)
per heartbeat.
 An average heartbeat is
72 beats per minute.
 Therefore an average
heart pumps 1.3 gallons
(5 Litres) per minute.

6. Contd….
Heart is divided into 4 chambers.
»Right Atria
»Left Atria
»Right Ventricle
»Left Ventricle

7. IMPULSE CONDUCTION & THE ECG
Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers

8. FIBRILLATION
• ‘ Fibrillate ’ means contract very fast
and irregularly.
Chaotic
Quivering
but
NO Heartbeat
NO Breathing

9. VENTRICULAR FIBRILLATION
Ventricular fibrillation results from
 Coronary occlusion
 Electrical shock
 Abnormalities of body chemistry
 The fibrillating EGG is
characterized by a lack of QRS
complexes .

10. ATRIAL FIBRILLATION
• Atrial fibrillation is a very fast , irregular
heart rhythm in the upper heart
chambers.
• Similar to normal waveform .
• Loss of ‘P’ waveform

11. DEFIBRILLATION
• Process in which a device sends an
electric shock to the heart to stop an
extremely rapid, irregular heartbeat,
and restore the normal heart rhythm.

12. WORKING

13. PRINCIPLE
Energy storage capacitor is charged at
relatively slow rate from AC line.
Energy stored in capacitor is then
delivered at a relatively rapid rate to
chest of the patient.
Simple arrangement involve the
discharge of capacitor energy.

14. ENERGY CALCULATIONS
The amount of energy ,WA in units
of Joule is given by,
C = Capacitance in Farads
V = Voltage across the capacitor
The amount of energy typically
stored in the capacitor of a
defibrillator, ranges from 50 to 400
Joule.
2
2
V
CWA 

15. ENERGY CALCULATIONS
• Internal
resistance of the
circuit, RD
• Paddle—skin
resistance, RE
• Thoracic
resistance, RT

16. ENERGY CALCULATIONS
• Then the energy absorbed by the
thorax,
W
RRR
R
W
TED
T
T


2

17. BLOCK DIAGRAM
POWER
SUPPLY
MANUAL
CONTROL
ENERGY
STORAGE
SYNCHRONIZER
ECG
MONITOR
PATIENT
S
T
A
N
D
B
Y
OPTIONAL
CHARGE DISCHARGE

18. WHAT IS JOULE?
• It is the unit of energy.
• “The energy released in one second by
a current of one ampere through a
resistance of one ohm”
• Also called as watt-second.
• The delivered energy is in the range of
50- 360 joule

19. DEFIBRILLATOR
MAKE: NIHON KOHDEN
MODEL: TEC 5500

20. GETTING FAMILIARISED
• Energy/ mode select
control
• Synchronizer lamp
• Synchronizer button
Microphone
• Charge button

21. Contd…
Record
key
ECG sensitivity
key
Event key
ECG lead
key
Multi
function
key
LCD display

22. Contd…
• charge button
• discharge
button

23. PADDLES

24. PADDLES
PADDLE PLACEMENT
There are two notable methods of
paddle placement recommended by
AHA
Anterior- Anterior
Anterior-Posterior

25. ANTERIOR- ANTERIOR
Place one paddle near the second or
the third right sternal border and the
other on the cardiac apex.
53.

26. ANTERIOR-POSTERIOR
One paddle on sternum and the other
on the left infra-scapular region.

27. MONOPHASIC WAVEFORM
DEFIBRILLATORS
•Current travels in
one direction
through the
patients heart
from one paddle
to another.
•Requires higher
energy levels (
200J-300J).

28. BIPHASIC DEFIBRILLATORS
• The Biphasic waveform
type defibrillator
delivers the current in
one direction during the
first phase and in
opposite direction
during the second
phase.
• Biphasic waveform
shocks of 200 J are
safe, equivalent or

29. TYPES OF DEFIBRILLATORS
Manual
Automatic
External
Internal
Automatic external
defibrillator

30. MANUAL DEFIBRILLATORS
 Clinical expertise is
needed to
 Interpret the heart
rhythm.
 To decide whether to
charge the defibrillator
and deliver the shock to
the patient
 Energy selection and
delivery is given to the
patient manually.

31. AUTOMATIC DEFIBRILLATORS
The defibrillator guides the
operator step-by-step through a
programmed protocol.
 It records and analyses the
rhythm and instructs the user to
deliver the shock.
 Small, simple, safe and light
weight .

32. EXTERNAL DEFIBRILLATORS
 Delivers the high energy
shock to patients.
 Applies externally on
patient's chest by using a
Defibrillator Paddle.
 The maximum energy
deliver to the patient is
about 360 Joule in
Monophasic & 200 Joules
in Biphasic Defibrillator.

33. INTERNAL DEFIBRILLATORS
Internal defibrillator
consist of sterilized
internal
Handle/Paddle
through which shock
is delivered directly
to the heart.

34. AUTOMATIC EXTERNAL
DEFIBRILLATORS ( AED)
AED can be classified as either
 Fully automatic
Semiautomatic.

35. Fully automatic models
• AED analyzes the ECG rhythm , decides and
determines whether a defibrillation counter-
shock is needed.
• The device automatically charges and
discharges.
Semi Automatic AED
 User does not require special medical
training.
 Used in public places – offices, airport,
shopping mall.
AED (CONTD…)

36. AED (CONTD…)
The electrodes transmit information about
the person's heart rhythm to a controller
in the AED.
The controller examines the electrical
output from the heart and determine if
the patient is in a shockable rhythm or
not and whether shock is needed.
The AED uses voice / visual prompts to
tell user.

37. IMPLANTABLE CARDIOVERTER-
DEFIBRILLATOR (ICD)
A implanted device that detects and terminates
life threatening episodes of VF / VT in high risk
patients.

38. IMPLANTABLE CARDIOVERTER-
DEFIBRILLATOR (ICD)

39. . IMPORTANT FACTORS
1.Time
Early defibrillation allows more
success or the longer period of VF, the
less success of defibrillation.
Early initiation of CPR improves the
success rate
>8 minutes neurological damage sets
in
>10 mins survival probability becomes
very low

40. Contd..
• 2. Energy Level
AHA Recommendation for Adults
First shock 200 j
Second shock 200 j to 300 j
Third and above shocks 360 j
AHA Recommendation For paediatrics
First shock 2 joules per Kg

41. Contd..
3. Paddle Size
• Adult paddles should be 8 to 13 cm
in diameter
• Child paddles should be 4.5 cm in
diameter.
• Infants use Anterior Posterior
position.

42. Contd..
4. Skin To Paddle Interface
Use the right gel
Too little gel increases possibility of
burn
Too much gel causes electric current to
arc from one electrode to another
If disposable paddles are used check
the expire date

43. PROCEDURE
Steps- Manual Defibrillator
Switch 'ON' the Machine
Wait for initialisation and self test
Apply gel to the paddles
Place them properly on the chest .
Select 'ENERGY' to be delivered
( energy in Joule) .
Press 'CHARGE' button
Wait for Charging to complete.

44. Contd..
This is usually denoted by a continuous
/long beep sound.
Apply pressure to the paddles ( 12 Kg of
pressure) .
Press both 'DISCHARGE' button
simultaneously .
Observe patient and monitor ECG
If required, defibrillate again .
When finished, turn off and clean the
paddles.

45. SPECIFICATION
Charging time maximum 5 sec for
200J.
 Momentary energy selection
access on front panel.
Should have adult and pediatric
paddles integrated on same handle.
Momentary charge key on front
panel and on the apex hand.

46. Contd…
Should have battery back up for 50
discharges of 200J.
 Should have ECG inputs through
paddles or 3 lead cables.
Should have display for heart rate.
Should have alarm for high and
low HR.

47. Contd…
 Should supply internal
defibrillation paddle, 2 bottle of
jelly, 12 roll of thermal paper.
 Should operate on mains 230V,
50Hz
 It should have
national/international standards for
safety/quality.

48. SAFETY PRECAUTIONS DURING
DEFIBRILLATION
Excessive Gels can cause arcing of
the current along the chest wall
Malfunction of permanent
pacemakers can result from placing
defibrillator pads or paddles near the
pacemaker
Defibrillation in the absence of an
ECG rhythm ('blind defibrillation') to
be avoided.

49. Alcohol should never be used
as conducting material for
paddles because serious burns
can result
 Never discharge the
Defibrillator in Air to check its
performance
Never discharge with paddles
shorted
Always clean the paddles after

50. • “Don’t call the world dirty because you forgot
to clean your glasses”