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.com Cheskes 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.


Thank You For Your Attention

Health & Medicine

Defibrillation - issues and challenges 2015