It contains everything related to the cardiac electric shock device

1. DC SHOCK
Prepared by. Aymen Nasr
Bachelor in Anesthesia

2. Types of shock
1 .defibrillation
2 cardioversion

3. Defibrillation
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• is a common treatment for life-threatening
cardiac dysrhythmias, ventricular fibrilla on and
pulseless ventricular tachycardia
Defibrilla on consists of delivering a therapeu c
dose of electrical energy to the heart with a device
called a defibrillator
External depolariza on of the heart to stop Vfib or
Vtach that has not responded to other maneuvers

4. Need for a defibrillator
“ Defibrillation” – Definitive treatment of life
threatening cardiac
arrhythmias – VENTRICULAR FIBRILLATION
PULSELESS VENTRICULAR TACHYCARDIA
Ventricular fibrillation- Irregular contraction of
muscle fibres
Ineffec ve pumping of blood from le ventricle
Steep fall in Cardiac output

5. PULSELESS VENTRICULAR TACHYCARDIA

6. Indications for Cardioversion
a) Supraventricular Tachycardia
b) Atrial fibrilla on
c) Atrial flu er
d) Ventricular Tachycardia with pulse

10. Types of defibrillators
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Manual external defibrillator
Automated external defibrillator (AED)
Implantable cardiac defibrillator (ICD)

11. Automated external
defibrillatorA unit based on computer technology and designed
to analyze the
heart rhythm itself, and then advise whether a shock is
required or not.
Designed to be used by lay persons, who require little
training.
Usually limited in the treatment of VF and VT rhythms.
Usually take time ( around 5-10 secs) in diagnosing
the rhythm
Can be found in places like corporate and
government offices,
shopping centers, airports, restaurants, sports stadiums,
schools and
universi es, community centers, fitness centers and health

12. Automated external defibrillator
Require self-adhesive electrodes(pads)
instead of handheld paddles
The ECG signal acquired from self
adhesive electrodes usually contains
less noise and has higher quality ⇒allows
faster and more accurate analysis of the
ECG ⇒be er shock decisions
“Hands off” defibrilla on - safer
procedure for the operator, especially if
the operator has li le or no training

15. Implantable cardiac defibrillator
An electronic device that constantly monitors heart rate and
rhythm.
When it detects a very fast, abnormal rhythm, it delivers energy to
the heart muscle. This causes the heart to beat in a normal rhythm
again.
Used for cardioversion, defibrillation, anti-tachycardia pacing &
bradycardia pacing.
2 parts :
a)The leads
b)The pulse generator

16. Manual external defibrillator
DC defibrillator
Clinician decides what charge
has to be set, depending on prior
knowledge and experience
Shock will be delivered through
paddles applied to the pa ent’s
chest.
Found in hospitals &
ambulances

21. position
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•
•
Anterior-lateral posi on ----
one – right of sternum below
clavicle (2nd & 3rd ICS)
other – le 4th or 5th ICS mid
axillary line
" Alterna vely anterior
posterior may be used: one
paddle is
placed in the le
infrascapular region
while the other is placed in
the le 5th- 6th intercoastal
space anterior axillary line.

22. Paddle Size
- Adult – large paddles
10-13 cm diameter
- Pediatric – small paddles <1yr
Infant <10kgs – 4.5cm
Children >10kgs – 8cm

23. General Safety
• Yourself, other staff
– Dry surface area
– Oxygen
• Chest wall
– GTN patch
– Jewellery
– Paddles / Pads not touching
• Technique
– One Person
– Two Person
– Adhesive Pads

24. Steps of Defibrillation
Give 2min CPR before analysis.
Power on ADE
A ach electrode pad.
Check rhythm.
CLEAR.
Give shock(120-200J)
Resume CPR for 2mins before analysis cardiac rhythm
again.
Consider giving – vasopressors / an -arrhythmic‟s
during subsequent
shock

25. Steps of cardiovertion
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- Check environment at procedure site
- Turn on defibrillator
- Anaesthe c technique as required
- Apply electrodes
- Press SYNC control
- Select applica onenergy level
- „3 clear‟ shout & look
- Deliver shock

26. How to DC shock
Get Crash cart ready
Turn on the machine and a ach adhesive electrodes (efficacy may be
be er with anterior posterior electrodes)
Choose the energy level.
IV-O2 -Monitor - Get a clearly visible trace on the monitor - eg, using
lead II.
Hit the 'sync' bu on - usually a blip or dot appears on the monitor,
marking each QRS complex.
Higher star ng energy is associated with be er success and fewer
shocks
Broad complex tachycardia and AF: monophasic - begin with 200 J, or
biphasic - 120-150 J.
Atrial flu er and narrow complex tachycardia: monophasic - 100 J, or
biphasic - 70-120 J.Charge.

27. How to DC shock
- Ensure all is clear around the bed including Oxygen
Discharge or shock
- there may be a 1- to 2-second delay as the
machine ensures synchronisa on
-Check rhythm a er the shock - if sinus rhythm, then stop; if not,
then you may need to deliver another shock at higher energy
levels.
Look for burns a erwards and obtain a 12-lead ECG.
Sync may not be successful in tachycardias where the QRS
complex
has a variable morphology.

28. Post Procedure Monitoring
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Monitor that pa ent stay in converted rhythm.
Keep pa ent well oxygenated.(SPO2 >98%)
Check serum K+ & Mg+ levels.
Maintain acid base balance.
Get 12 lead ECG a er procedure.
Check for chest pain & access.
Get CPK & Troponin done.
Access pa ents skin.

29. Post Procedure Monitoring
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- Record delivery energy & result
- If successful response
check for peripheral pulses, BP, Airway patency
- Inspect skin under the padds
- If not successful, check & reassess

30. Complications
Most common- Harmless arhhythmias like atrial/ventricular
premature beats.
Serious complications :
a) ventricular fibrilla on
b) Thrombo-embolisa on
c) Myocardial necrosis
d) Myocardial stunning
e) Pulmonary edema
f) Painful skin burns

31. Contra-indications
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Any arrhythmia with enhanced automaticity
like
Catecholamine induced tachycardia
Digitalis toxicity induced arrhythmias
Multi focal atrial tachycardia

32. Daily low energy test
Step 1 : Put the defibrillator on Battery mode and ensure machine
is
disconnected from the AC power supply .
Turn the selector switch to ON and select Manual mode
Select leads to PADDLES/PADS
Step 2 : Ensure the universal cable is connected to the paddles
Place paddles in paddle wells
Step 3 : Select the ENERGY to 30 J
Step 4 : Press the CHARGE button
Step 5 : The unit charges to 30J, then the red LED charge
indicator
illuminates and the charge tone sounds

33. Daily low energy test
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Step 6 : Ensure DEFIB 30J READY displays on
screen
Step 7 : Press and hold both paddles SHOCK
buttons
Step 8 : The unit discharges. The TEST OK
message displays and the
red LED turns off
Step 9 : The above TEST OK message conforms
that low energy
circuits are in proper working condi on

34. Thank you so much.

35. Synchronized cardioversion
• is a LOW ENERGY SHOCK that uses a sensor to
deliver electricity that is synchronized with the peak
of the QRS complex (the highest point of the R-
wave). When the “sync” op on is engaged on a
defibrillator and the shock bu on pushed, there
will be a delay in the shock. During this delay, the
machine reads and synchronizes with the pa ents
ECG rhythm. This occurs so that the shock can be
delivered with or just a er the peak of the R-wave
in the pa ents QRS complex.

36. • Synchroniza on avoids the delivery of a LOW
ENERGY shock during cardiac repolariza on (t-wave)
. If the shock occurs on the t-wave (during
repolariza on), there is a high likelihood that the
shock can precipitate VF (Ventricular Fibrilla on).

37. indications for synchronized
• The most common indica ons for synchronized
cardioversion are unstable atrial fibrilla on, atrial
flu er, atrial tachycardia, and supraventricular
tachycardias. If medica ons fail in the stable pa ent
with the before men oned arrhythmias,
synchronized cardioversion will most likely be
indicated.

38. Unsynchronized cardioversion
• (defibrilla on) is a HIGH ENERGY shock which is
delivered as soon as the shock bu on is pushed on
a defibrillator. This means that the shock may fall
randomly anywhere within the cardiac cycle (QRS
complex). Unsynchronized cardioversion
(defibrilla on) is used when there is no coordinated
intrinsic electrical ac vity in the heart (pulseless VT/
VF) or the defibrillator fails to synchronize in an
unstable pa ent.

39. • For cases where electrical shock is needed, if the
pa ent is unstable, and you can see a QRS-t
complex use (LOW ENERGY) synchronized
cardioversion. If the pa ent is pulseless, or if the
pa ent is unstable and the defibrillator will not
synchronize, use (HIGH ENERGY) unsynchronized
cardioversion (defibrilla on).

40. Defibrillator Wave forms
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Monophasic wave form : Energy is delivered
through the patient’s
chest in a “single direc on”
Biphasic wave form : Energy is delivered
through the patient’s
chest in two direc ons.
Low-energy biphasic shocks may be as
effective as higher-energy
monophasic shocks

43. References
ACC/AHA Guidelines 2015 for adult advanced cardiac life support
David J Williams, Fiona J Mc Gill. Physical principles of defibrillator,
Anesthesia and intensive care medicine; 2003.
LL Bossaert. Fibrillation and defibrillation of heart : British journal
of
anesthesia 1997 ;79:203-213
Kundra P, Vishnu Prasad PS, Padmavathi V, Siva T. Defibrillator
maintenance policy. Indian J Anaesth 2015;59:685-7.
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