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Three Part Question

[In a patient with out of hospital cardiac arrest]does [the use of the autopulse mechanical CPR device when compared to manual CPR][ improve survival to discharge from hospital].

Clinical Scenario

You are dispatched to a house in which a 45yr old man has collapsed. He is in cardiac arrest when you arrive. During the resuscitation process, you and your team wonder if the use of the mechanical autopulse device to provide chest compressions during the resuscitation will result in a better outcome for the patient.

Search Strategy

Medline with ovid interface: 1950- 2007 Jan Week 3
Embase: 1974- 2007 Feb week 2
Cochrane
MEDLINE: [pre-hospital cardiac arrest.mp, pre-hospital.mp, out of hospital.mp, community.mp, cardiac arrest.mp, heart arrest.mp, pulseless electrical activity.mp, PEA.mp, ventricular fibrillation.mp, VF.mp, asystole.mp, heart stoppage.mp, heart arrest] / [cardiopulmonary resuscitation, automated chest compression device.mp, automated cpr device.mp, automated cardiopulmonary device.mp, Electric Countershock/ or Death, Sudden, Cardiac/ or Advanced Cardiac Life Support/ or Ventricular Fibrillation/ or Cardiopulmonary Resuscitation/ or Emergency Medical Services/ or Heart Arrest/ or automated cpr device.mp., automated cardiopulmonary device.mp. automatic load distributing band chest compression device.mp. autopulse.mp. load distributing band cpr.mp, load distributing band cardiopulmonary resuscitation device.mp, LDB-CPR.mp, automated CPR.mp., automated cardiopulmonary resuscitation.mp., Hemodynamic Processes/ or Cardiopulmonary Resuscitation/ or Heart Massage/ or Heart Arrest/ or manual cardiopulmonary resuscitation.mp. or Resuscitation/, manual chest compressions.mp., EMS CPR.mp, BLS CPR.mp, basic life support.mp, automated heart massage.mp,] / [survival.mp., discharge.mp.] limit to humans and english
EMBASE: "((((cardiac arrest) OR (prehospital cardiac arrest) OR (out of hospital cardiac arrest) OR (heart arrest) OR (PEA) OR (pulseless electrical activity) OR (VF) OR (ventricular fibrillation) OR (asystole) OR (heart stoppage)) AND ((cardiopulmonary resuscitation) OR (automated chest compression device) OR (autopulse) OR (load distributing band cpr) OR (load distributing band cardiopulmonary resuscitation device) OR (LDB-CPR) OR (automated cardiopulmonary resuscitation) OR (automated cardiopulmonary resuscitation) OR (Heart Massage) OR (manual cardiopulmonary resuscitation) OR (EMS CPR) OR (BLS CPR) OR (basic life support) OR (automated heart massage)) AND ((survival) OR (discharge))). Limit to English

Search Outcome

Medline- 2746 papers- 3 relevant
Embase- 871- no additional papers
Cochrane Review- no additonal papers
Other- 1x poster presentation

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Casner et al feb-dec 2003 San Francisco USA	262 out of hospital cardiac arrests attended to by the San Francisco Fire Department	Retrospective case controlled study	Return of sustained spontaneous circulation at arrival to hospital	:	Time to dispatch of autopulse. M-CPR- 7+/-3mins A-CPR 15+/- 5mins Manual CPR group had significantly shorter arrest duration and treatment duration. Failure to match duration of manual CPR prior to use of autopulse when creating case controls Retrospective Small numbers
Ong et al 2001-2005 Virginia USA	Out of hospital cardiac arrests attended to by Richmond Ambulance Authority	Phased non randomized observational study :Retrospective chart review of manual CPR patients 1/1/2001- 31/3/2003 and autopulse patients 20/12/2003- 31/3/2005 499 patients in manual CPR group 284 patients in autopulse group	return of spontaneous circulation	manual CPR 101/499 20.2% [16.9-24.0]	Retrospective only reliable time intervals were first response times significantly faster response time in autopulse CPR group- p=0.03 institution of hypothermia protocol into the autopulse group- p<0.001 in one hospital time to apply device not documented
			survival to hospital admission	manual- 11.1%
			survival hospital discharge
			neurological function at discharge
Halstrom et al july-2004- march 2005 multicentre trial USA and Canada (5 sites)	Out of hospital cardiac arrests	Prospective Cluster randomised control trial with cross-over 394 received autopulse CPR 373 received manual CPR	survival with spontaneous circulation 4 hours after the 911 call		3 different options for resus intervention option 1- 6 sec pulse check then CPR intervention option 2 immediate manual CPR +/- shock then CPR intervention option 3 analysis+/- shock then CPR intervention site C changed option mid- way through significant differences in autopulse group- more likely to receive adrenaline- p=0.03 longer time intervals to first shock for VF/VT- p=0.01 more likely terminisation of resus effort p=0.01
			Discharge from hospital
			Cerebral performance category score at discharge
Swanson et al. Florida, USA	Out of hospital cardiac arrests treated by the Evac ambulance service, Florida	Retrospective review 118 cardiac arrests with autopulse used 405 cardiac arrests with manual CPR	survival to an emergency department with measurable spontaneous pulse		Retrospective Small numbers Looking at short term outcome only Poster presentation- exact details of the study unavailable (limited to abstract)

Comment(s)

As shown in the table above there is a limited amount of research available on the use of the Autopulse in a pre-hospital cardiac arrest. Most of the studies are retrospective and have small numbers of patients which makes it very difficult to draw conclusions due to the inherant faults in retrospective reviews. Hallstrom et al.'s multicentre randomised trial was perhaps the best attempt at trying to answer the question. However there were some difficulties associated with this trial- particularly the significant differences in autopulse group who were more likely to receive adrenaline and have longer time intervals to first shock for VF/VT. The study was further complicated by site C changing its initial resus interventions mid way through the trial. This study was halted following interim analysis showing no difference in survival at 4 hours and a significantly worse survival to discharge and overall cerebral performance in the autopulse group. When one analyses the outcome for different types of arrest however the studies show a trend towards increased survival in the asystole and PEA groups when autopulse was used. This effect was significant in two of the retrospective studies and approaching significance in the prospective multicentre trial.

Clinical Bottom Line

Currently there is insufficent evidence to support the use of Autopulse in pre-hospital cardiac arrest and may actually be associated with a worse outcome ( particularly in patients with VF/ pulseless VT in where there is a delay to defibrillation). Further studies are necessary to evaluate improved survival in the asytole and PEA arrest groups

References

1. Casner et al The impact of a new CPR assist device on rate of return of spontaneous circulation in out of hospital cardiac arrest Prehospital Emergency Care Jan- Mar 2005; 9;1, 61-67
2. Ong et al Use of a automated, load-distributing band chest compression device for out of hospital cardiac arrest resuscitation JAMA June 14, 2006-vol295 (22) 2629-2637
3. Halstrom et al Manual chest compression vs use of an automated chest compression device during resuscitation following out of hospital cardiac arrest JAMA June 14, 2006- Vol295(22)2620-2628
4. Swanson et al. Effect of a CPR assist device on survival to Emergency Department Arrival in Out of Hospital Cardiac Arrest Circulation 112(17): Oct 25, 2005, II-1106