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JAMA 2002,Weisfeldt & BeckerResuscitation After Cardiac Arrest

A 3-Phase Time-Sensitive Model

Electrical Phase of VF

Defibrillation

Circulatory Phase

Compression

Defibrillation

Metabolic Phase

Hypothermia

Other Therapies

ECPB

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Is the best treatment for VF herethe same as here?

0-4 min 4-10 min > 10 min

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Electrical Phase

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3 Phases of Cardiac Arrest

Electrical Phase of VF

Defibrillation

Circulatory Phase

Compression

Defibrillation

Metabolic Phase

New therapy

AEDs

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Casino Study: Survival--Time is of

the Essence

Trained Security Officers in AEDs

105 patients, VF arrest

92 witnessed arrests Average time, collapse to shock: 4.4 minutes

Valenzuela et al. NEJM, 2000

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Casino Study: Results

74%

49%

0%

10%

20%

30%

40%50%

60%

70%

80%

Survival to Hospital Discharge

< 3 min

>3 min

All survivors neurologically intact

Valenzuela et al. NEJM, 2000

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Circulatory Phase

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CPR Prior to Defibrillation

Shock patients as soon as recognized

Efficacy decreases with each passing minute

Study of immediate shock vs. 3 minutes of

chest compressions prior to shock 200 out-of-hospital cardiac arrest patients

3 minutes of chest compressions offered no

advantage in outcomes for population as awhole

But

Wik et al. JAMA, 2003

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Wik > 5 min ambulance

response

89% of survivors good neurologic outcome

Wik et al. JAMA, 2003

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Metabolic Phase

ATP Depletion

Calcium Influx

Free Radical

Production

Endothelial

Dysfunction

MitochondrialDysfunction

Ion PumpDysfunction

MetabolicAcidosis

Apoptosis

Inflammation

Permeability ofthe Blood

Brain Barrier

Pro-

coagulation

Early Injury Late Injury

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Time

%S

urviving

SHOCK < 3 min: 74%

CPR

ROSC

Hospital

d/c, 10%

To summarize: 3 phases of arrest

Arrest!

Valenzuela et al. NEJM, 2000

Penn Pre-TH

OHCA Data

34%

E C M

> 5 min, CPR 1st

: 22%

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Time

%S

urvivin

gWhat is happening?

Cellular level injuryEndothelial damage

Mitochondrial dysfunction

Hypothermia

Damage observed after restoration

of blood flow to ischemic tissues

To summarize: reperfusion injury

Vanden Hoek et al AJP 1996

10%

19%

34%