earlydefibrillation- automated external defibrillators

8/8/2019 EarlyDefibrillation- Automated External Defibrillators

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Automated External Defibrillation


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Chain of Survival

Early access

Early CPR

Early defibrillation Early advanced life support


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Defibrillation is Part of BLS

Basic Life Support includes CPR and defibrillation

Early defibrillation with an automated externaldefibrillator (AED) has established benefit

The principle of early defibrillation suggests that the firstperson to arrive at the scene of a cardiac arrest shouldhave a defibrillator

This principle is now internationally accepted

Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care p. I-68


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Electrical Conduction System of theHeart

Left AtriumAtrioventricular Node

Bundle of His

Left Bundle Branch

Left Ventricle

Purkinje FibersRight Ventricle

Right Bundle Branch

Right Atrium

Sinoatrial Node

Internodal Pathways


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Normal Conduction Pathway in the Heart

and the ECGSinoatrial (SA) Node

Atrioventricular (AV) Node

Left Bundle Branches

Right Bundle Branch

Purkinje Fibers

P = Atrial Depolarization

QRS = Ventricular Depolarization

T = Ventricular Repolarization

P T

QRS


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Normal Sinus Rhythm

Sinoatrial Node

12:56 29MAR96 PADDLES X1.0 HR = 74


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Ventricular Tachycardia

12:57 29MAR96 PADDLES X1.0 HR = 214


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Ventricular Fibrillation

12:57 29MAR96 PADDLES X1.0 HR = ---


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Defibrillation: The Only EffectiveTreatment for Ventricular Fibrillation

300 JOULES DEFIB 20:29 01APR96 PADDLES X1.0 HR = ---


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Thanks, I needed that!


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Why Early Defibrillation?

VF most frequent initial rhythm in sudden cardiac arrest

Defibrillation most effective treatment

Probability of defibrillation success diminishes with time VF tends to rapidly deteriorate into asystole

Textbook of Advanced Cardiac Life Support, Chapter 20, 1990; p. 287


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Asystole

15:17 29MAR96 PADDLES X1.0 HR = ---


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10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9

%

Success

Time (minutes)

Success rates decrease7-10% each minute

* Non-linearAdapted from text: Cummins

RO,Annals Emerg Med. 1989,

18:1269-1275.

Resuscitation Success vs. Time*


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Early Defibrillation Effectiveness

Rural and urban U.S. studies

Substantial increases in survival

Textbook of Advanced Cardiac Life Support, Chapter 20, 1990, p. 289

30

25

20

15

10

5

0

King County

Washington

Iowa Southeast

Minnesota

Northeast

Minnesota

Wisconsin

Before

After

%

Surviva

l


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Early Defibrillation by Police andParamedicsRochester, MN

Survival toNumber hospital discharge

First shocked 31 18 (58%)by police

First shocked 53 23 (43%)by paramedics

Overall survival to hospital discharge = 49%

White RD, et al.Annals of Emerg Med. 1996;28:480485.


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Time to DefibrillationThe Clock is Ticking

Recognize cardiac arrest 1 min.

Activate internal emergency response 1 min.

Call EMS / dispatch vehicle 1 min.

Aid car sentarrives on scene 6 min.

Locate victim and deliver shock 2 min.

Total Elapsed Time = 11 min.


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AEDs are Well Suited for Use byNon-Traditional Responders

Todays AEDs are more practical for usein the workplace and public places

Voice prompts are more intuitive

Non-rechargeable batteries are the norm

AEDs do daily self tests and are virtually

maintenance free


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Early Defibrillationby Security Officers: Casino Study

Landmark study: AED use by nontraditionalresponders in out-of-hospital cardiac arrest

Security Officers in various gaming casinoswere trained to use AEDs

Goal: to deliver first shock within 3 minutes ofpatient collapse

Valenzuela TD, et al: NEJM 2000; 343: 1206-09.Valenzuela TD, et al: NEJM2000; 343: 1206-09.


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Results

Mean time from collapse tofirst shock

Mean time from collapse to

medic arrival

All VF patients surviving tohospital d/c

Witnessed VF patients

surviving to hospital d/c

Valenzuela TD, et al: NEJM2000; 343: 1206-09.

4.4 min.

9.8 min.

53%

59%


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7%

49%

74%

Survival Rates for Witnessed VF

100

Valenzuela TD, et al: NEJM 2000; 343: 1206-09.

90

80

70

60

50

40

30

20

10

0

Percent

Shock 3 min. after

collapse (27/55)National

Average

Valenzuela TD, et al: NEJM2000; 343: 1206-09.


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Automated External Defibrillators

Analyze patient ECG only for unconscious, pulseless victims with

no spontaneous breathing and no signs of circulation

Determine via computer algorithm shockable ornon-shockable rhythm

Advise operator SHOCK or NO SHOCK

Shock ventricular fibrillation and certainventricular tachycardias


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LIFEPAK 500

Automated External

Defibrillators


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How to Defibrillate

Verify the victim is unconscious, not breathing,without a pulse or signs of circulation

Turn on AED and attach electrodes

ANALYZE heart rhythm

Follow the voice prompts and screen messages


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Defibrillation Electrode Placement

Anterior-lateral placement

Lateral

Anterior


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Next time, remove his shirt!


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Defibrillation Electrode Placement

Correct electrode position optimizes the amount ofcurrent flowing through the ventricles

Correct electrode position Incorrect electrode position


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Safety First

Attach the defibrillator only to someone notbreathing and without a pulse or signs of circulation

Make sure no one is touching the victim

Be sure the electrodes are firmly adhered tothe victims chest

Move oxygen away from the rescue effort beforedefibrillation


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You should have said clear!


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Who is Using AEDs Today?

Flight Attendants

Firefighters

EMTs

Corporate EmergencyResponse Teams

Security Officers

Police

Golf Pros

Lifeguards

Health Club Employees


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Advantages of AEDs

Eliminates need to recognize rhythms

Personnel with less training can defibrillate

May reduce time to therapyaccess to moretreatable rhythms

Makes early defibrillation practical and achievable


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earlydefibrillation- automated external defibrillators

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