Defibrillation - issues and challenges 2015

Defibrillation: Issues and
Challenges
Dr. K.S. Chew
School of Medical Sciences
Universiti Sains Malaysia

Conflict of Interest
•  No conflict of interest to declare
www.PresentationPro.com

Contents
•  What are already known about defibrillation
•  CPR before defib – how long should we do?
•  Effect of perishock pauses.
•  Hands-on defibrillation
•  CPR devices as an alternative. But how effective?
•  More AEDs in public places in Malaysia?

What Are Already Known
•  Defibrillation works in VF/pulseless VT (Larsen et. al.
Ann Emerg Med. 1993;22:1652 -1658)
•  It should be given early
–  IHCA (Chan et al N Engl J Med . 2008;358:9–17) and
–  OHCA (Holmberg et al. Resuscitation. 2000;44:7–17)
•  It should be integrated with CPR (Larsen et. al.
Ann Emerg Med. 1993;22:1652–1658)
–  For every minute without CPR from collapse to
defibrillation, survival rate decreases 7% to 10%

Lars Wik et al (2003):
•  Ambulance response time <5 min, CPR 1st vs Defib
1st: no difference (survival to discharge)
•  Ambulance response time >5 min, CPR first for 3
min 22% (14/40); Defib first 4% (2/41), OR 7.42
(95% CI 1.61-34.3), p = 0.006
Wik L et al. JAMA 2003. 289:1389-95

AHA Guidelines 2010
•  OHCA
–  witnessed: CPR first, shock ASAP when ready
–  Unwitnessed: CPR first, shock ASAP when ready
(For how long? Full 5-cycle of CPR??)
•  IHCA
–  unwitnessed: CPR first, shock ASAP when ready
–  Witnessed: ?? CPR first
“time from onset of VF/pulseless VT to defibrillation
within 3 minutes”

How Much CPR Before Defib?
Stiell et al. N Engl J Med 2011;365(9):787-97

•  10 Resuscitation Outcomes Consortium (ROC)
sites in the U.S. and Canada.
•  P = N = 9933 non-traumatic OHCA (unwitnessed)
•  I = CPR for 30 to 60s before defib (until pads were
applied) or
•  C = CPR for 180s before defib
•  O = Survival to hospital discharge with satisfactory
neurological outcome

•  Survival to hospital discharge with satisfactory
neurological function was 5.9% in both groups.
•  Delaying analysis of cardiac rhythm during EMS-
administered CPR provided no advantage.

Perishock Pauses
Cheskes et al. Circulation. 2011;124(1):58-66.

Perishock Pauses
•  Definition: Perishock pauses are pauses in chest
compressions before and after defibrillation
•  N = 815 patients requiring at least one defibrillation;
11 centers in North America
•  Association between pause durations and
outcomes were analyzed
•  Primary outcome: survival to hospital discharge

www.PresentationPro.comCheskes et al. Circulation. 2011;124(1):58-66.

Results
Survival to Hospital Discharge as a Function of Maximum*
Shock Pause

Results
•  Odds of survival were significantly lower if:
•  preshock pause ≥20s vs preshock pause <10s
(OR 0.47; 95% CI 0.27 to 0.82) and
•  perishock pause ≥40s vs perishock pause <20s
(OR, 0.54; 95% CI 0.31 to 0.97)
•  Postshock pause – not associated with a significant
change in the odds of survival
•  survival to discharge decreases 18% and 14% for q
5s increase in preshock and perishock pauses (up
to 40s and 50s), respectively

Keep Hands On While Defibrillation?
•  Hands-on defibrillation minimizes pre-
shock & peri-shock pauses in cardiac
compressions.
–  For every 5-second increase in both pre-
shock and peri-shock, a 18% & 14%
decrease in survival to hospital
discharge up to 40 and 50 seconds,
respectively (Cheskes et al. Circulation.
2011 Jul 5;124(1):58-66. )
But are rescuers who use this technique at risk for
exposure to electric shock?

Lemkin et al. Resuscitation. 2014 Oct;85(10):1330-6.

•  Cadaveric study, 6
cadavers
•  Voltage measurements
while rescuers
performed defibrillation
with 360J on cadavers.
•  Cadavers not grounded

•  Results:
•  rescuers would be exposed to between 200 and
827 volts, depending on the cadaver and electrode
location, and received between 1 and 8 joules of
electrical energy, an amount that exceeds
recommended exposure levels.

Summary
•  Give some chest compression while preparing for
defib
•  How long? 1 min until defib is ready or a full 3-min?
•  No difference! Probably should just shock!
•  DO NOT keep hand-off for >10s before shock
•  But be safe! Keep hands off while shock is
delivered.

CPR Devices
Should you buy one? Is it effective? Which one?
What’s the evidence so far?
A solution to continuous CPR when shock is
delivered

Two Types of CPR Devices
•  Load-distributing band CPR
devices (LDB)
–  Provide circumferential thoracic
compressions
•  Piston-driven CPR device (PD)
–  Provide sternal compressions
•  In preclinical settings, CPR
devices improve coronary
perfusion, cardiac output, ROSC.

Why CPR Devices?
Advantages
1.  Overcomes rescuer fatigue
2.  Provides effective and consistent compression
3.  Frees rescuers to perform other procedures
4.  Allows defibrillation during on-going compression
5.  Minimizes peri-shock delay
Disadvantages
1.  Technical difficulties in applying devices
2.  No one-size fit all

The Use of CPR Devices: What’s the
Evidence?
Westfall M, Krantz S, Mullin C, Kaufman C. Mechanical versus manual chest
compressions in out-of-hospital cardiac arrest: a meta-analysis. Crit Care Med.
2013;41(7):1782-9.

Are CPR Devices Effective In Clinical
Setting?
•  A meta-analysis by Westfall et al in Crit Care Med.
2013;41(7)
•  P = OHCA victims (N = 6,538)
•  I = CPR devices (both LDB & PD) CPR
•  C = Manual CPR
•  O = ROSC (defined as palpable pulse with
measurable BP for at least 1 min)
Westfall M, Krantz S, Mullin C, Kaufman C. Mechanical versus manual chest
compressions in out-of-hospital cardiac arrest: a meta-analysis. Crit Care Med.
2013;41(7):1782-9.

12 papers finally accepted for the meta-analysis
Only English-language articles were searched

Test for Heterogeneity
•  A random-effects model used
Note:
•  When the studies’ results differ only by the
sampling differences (homogeneous cases), a
fixed-effects model is used
•  When the study results differ by more than the
sampling differences, which means including
variations in study design (heterogeneous
cases), a random-effects model is used

Results
•  12 papers analyzed
•  A total of 6,538 subjects with 1,824 ROSC events
•  Combined analysis of both types of CPR devices:
•  Treatment effect in favor of higher odds of ROSC
with mechanical CPR devices (odds ratio 1.53 [95%
CI, 1.32, 1.78]; p < 0.001)

Piston-Driven CPR (PD-CPR) devices vs
Manual CPR (M-CPR)

Load-distributing CPR (LDB-CPR) devices
vs Manual CPR (M-CPR)

Conclusion
The combined meta-analysis of two types of
CPR devices compared with manual chest
compressions showed a significant
improvement in ROSC rates with
mechanical devices….when analyzed
separately, only the LDB-CPR device was
found to be superior to manual chest
compressions with odds of achieving ROSC
being 1.6 times greater

The CIRC Trial
Wik L, Olsen JA, Persse D, Sterz F, Lozano M, Jr., Brouwer MA, et al. Manual vs.
integrated automatic load-distributing band CPR with equal survival after out of
hospital cardiac arrest. The randomized CIRC trial. Resuscitation. 2014;85(6):741-8.

CIRC Trial
•  Randomized, unblinded, controlled group
sequential trial involving 5 centers: 3 US sites, 2
European sites, N = 4231 cases; industry-funded
•  P = OHCA victims
•  I = IA*-LDB device (n = 2099)
•  C = Manual CPR (n = 2132)
•  O = survival to hospital discharge (primary)
•  Caveat: excluded cases where the body sizes were
too big for the device
*integrated = manual CPR was provided while device was applied

CIRC Trial: Results
Manual CPR
(n = 2132)
LDB CPR
(n = 2099)
Adjusted OR
Survival to
hospital
discharge
233 (11.0%) 196 (9.4%) 1.06
(CI: 0.83 –
1.10)
Secondary outcome:
Sustained
ROSC until
adm
689 (32.3%) 600 (28.6%)
24-hr survival 532 (25.0%) 456 (21.8%)

Conclusion
•  LDB device is as good as manual compression
•  LDB eliminates rescuer fatigue
•  LDB allows CPR in spaces and situations where
human could not provide effective compressions

The PARAMEDIC Study
Perkins GD, Lall R, Quinn T, Deakin CD, Cooke MW, Horton J, et al. Mechanical versus
manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic,
cluster randomised controlled trial. Lancet. 2015;385(9972):947-55.

The PARAMEDIC Study
•  Randomized, pragmatic design to study the clinical
outcomes of a piston-driven CPR device
(LUCAS-2) vs manual CPR
•  Intention-to-treat analysis
•  P = OHCA victims
•  I = Piston-driven CPR device, Lucas-2 (n = 1652)
•  C = Manual CPR (n = 2819)
•  O = survival at 30 days

Pragmatic vs Explanatory Design
(coined by Schwartz & Lellouch, 1967)
Pragmatic Explanatory
Aim To evaluate the
effectiveness of the
intervention in a broad
and diverse routine
clinical practice
To evaluate the efficacy of an
intervention in a well-defined
and controlled setting (ideal/
optimal environment)
Sample Larger sample size Smaller sample size
Confounders Poorly controlled Controlled as much as
possible
Generalizability Probably more
generalizable
Less generalizable
Bottomline whether an intervention
actually works in real
life
if and how an intervention
works

Note: “Survived event” is defined as sustained ROSC until hospital admission from ED

†Reasons LUCAS-2 not used:
• 78 because of crew not
trained;
• 168 because of crew error;
• 26 no device in vehicle;
• 102 unsuitable patients (58
patient too large, 22 patient too
small, 22 other reason–eg, chest
deformity),
• 14 device issues;
• 140 not possible to use
device;
• 110 reason unknown.
Reasons for LUCAS-2 use in
control group were crew error.
Perkins et al Lancet. 2015;385(9972):947-55.

Smekal et al Resuscitation. 2011;82(6):702-6.
Rubertsson et al. The LINC randomized trial. JAMA. 2014;311(1):53-61.

The PARAMEDIC Study
“We noted no evidence of improvement in 30 day
survival with LUCAS-2 compared with manual
compressions. On the basis of ours and other recent
randomised trials, widespread adoption of mechanical
CPR devices for routine use does not improve
survival”
Conclusion:

Summary Of What’s Discussed So Far
•  Meta-analysis by Westfall et al (2013): LDB
device seems better than manual compression in
achieving ROSC. Piston-driven device is no better.
•  CIRC trial (2014): IA-LDB is no better than manual
compression in survival to hospital discharge
•  PARAMEDIC study (2015): Piston-driven device is
no better than manual compression in survival to 30
days

A Good Reason To Get A CPR Device?

“The main thing…is
to keep the main
thing the main thing”
– Stephen Covey
“Providing quality compression
and minimize interruptions”

Placing More Automated External
Defibrillators In Public Places in Malaysia

“A defibrillator and code cart should be in close proximity to
enable defibrillation of any patient in cardiac arrest within 2
minutes…”
“…placement of AEDs in areas where time from arrest to
arrival of a defibrillator would be >3 minutes…..”
Morrison LJ et al. Circulation. 2013;127(14):1538-63.

More public places with AEDs
in Malaysia?
Which public places?

A Public Access Defibrillator Act

List of Places with AEDs Under Manitoba
Defibrillator Public Access Act
•  Fitness clubs, gyms,
swimming pools and
other facilities
–  >150 members, or >20
hours of indoor group
physical-activity
programs are held in the
majority of weeks in a
year
•  Community Centers
•  Golf Courses
•  Colleges, universities
•  Airports, train stations
•  Casinos
•  Homeless shelters
•  Major shopping centers
•  Museums, other
popular destinations
•  City Hall
•  Law Courts

Placing AEDs in Vending Machines?

Other Ethical and Legal Issues, Privacy..

Civil Responsibility, Vandalism, Theft

Summary
•  CPR before defib to be performed until defibrillator
is ready
•  Minimize preshock pauses to <10s
•  Hands-on defib is not recommended. Be safe!
•  CPR devices as an alternative for hands-on
defibrillation.
•  CPR devices are not shown to have an advantage
over high quality manual CPR
•  AEDs in public places – political will needed.

Defibrillation - issues and challenges 2015

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