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Three Part Question

In [adults who have sustained an out-of-hospital atraumatic cardiac arrest] is [mechanical chest compressions more effective than conventional cardiopulmonary resuscitation] to [improve survival to hospital discharge].

Clinical Scenario

During a morbidity and mortality conference at a local Emergency Medical Services (EMS) agency, a paramedic questioned the effectiveness of a new mechanical device used for chest compressions during cardiac arrest. As the EMS medical director, you recall at least one recent randomized clinical trial that addresses this question.

Search Strategy

Medline 1996-07/15 using OVID interface, Cochrane Library (2015), and Embase

[([mechanical.mp OR device.mp OR automated.mp OR LUCAS.mp or AUTOPULSE.mp)] AND [(cardiac arrest.mp) OR (cardiopulmonary resuscitation.mp) OR (heart massage.mp) OR (CPR.mp) OR (chest compression.mp)] AND [(out of hospital.mp)]. Limit to clinical trials and English language.

Search Outcome

109 papers were identified of which two recent RCTs and a systematic review answered the clinical question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Rubertsson S, Lindgren E, Smekal D, et. al January 2014 Sweden	2589 adult patients with out-of-hospital cardiac arrest requiring cardiopulmonary resuscitation (CPR) between January 2008 to August 2012 in Sweden, the United Kingdom and the Netherlands. Patients randomized to receive mechanical or manual CPR.	Multicenter Randomized Clinical Trial	Primary outcome was 4-hour survival after return of spontaneous circulation (ROSC). Secondary outcomes were ROSC, arrival to emergency department (ED) with palpable pulse, and survival with good neurological outcome.	No significant difference in 4-hour surivival between groups with manual CPR group survival of 23.6% vs 23.7% (95% CI -3.3% to 3.2%) in the mechanical and manual groups respectively. No difference in surival or neurological outcomes at 6 months.There were 23 reported adverse events in the mechanical CPR group including 7 serious events vs 3 serious events in the manual CPR group	Unable to blind providers from intervention between groups. Resuscitation deviated from Advanced Cardiac Life Support (ACLS): delivered countershock irregardless of initial rhythm and 3 minute CPR periods. There was a difference in patients who received at least 1 defibrillation (75% in mechanical group vs 45% in manual group).Time to first defibrillation was delayed by 1.5 minutes on average in mechanical group. Patient with shock delivered prior to EMS arrival were excluded, which may have affected survival.
Perkins GD, Lall R, Quinn T, et. al. March 2015 United Kingdom	4471 adult patients with out-of-hospital arrest who were evaluated by four UK ambulance services between April 2010 to June 2013. Patients randomized to mechanical CPR vs manual chest compression.	Randomized control trial	Primary outcome was survival to 30 days after arrest. Secondary outcomes were ROSC at admission, survival at 3 and 12 months and favorable neurological outcomes at 3 months	30 day survival was similar in the mechanical CPR group vs. the control group (6% vs 7& with 95% CI 0.64-1.15). There was also similar rates of ROSC at admission and survival at 3 months. There was a lower rate of favorable neurological outcomes in the mechanical CPR group. There were 7 adverse outcomes in the mechanical CPR group but no serious events.	Only 60% of the 1652 patients randomly assigned to the mechanical CPR group received the intervention. Providers are unable to be blinded to intervention. The quality of manual CPR was not consistently monitored.
Brooks SC, Hassan N, Bigham BL, et. al. February 2014 Canada	1166 patients from six trials with either out-of-hospital or in-hospital cardiac arrest	Meta-analysis of randomized control trials (RCTs), cluster RCTs and quasi-RCT.	Primary outcome was survival to hospital discharge with good neurological function. Secondary outcomes included ROSC, survival to admission, short term survival (less than 30 days), land long term survival (greater than 30 days).	One study reported survival to discharge with good neurological function with reduced survival with mechanical vs manual CPR (95% CI 0.21 to 0.79). 4 studies showed increased ROSC and survival with mechanical CPR, but these results were not statistically significant.	Significant heterogeneity between studies. Many studies did not report specifics on performed CPR, study participants and adverse events. Certain studies had significant delays in time to intervention.

Comment(s)

Sudden cardiac arrest is significant cause of morbidity and mortality. The initial goals in treatment include cardiopulmonary resuscitation (CPR). In trials comparing mechanical CPR devices versus conventional manual CPR, survival outcomes are similar between the two groups. In these studies, there were few but potentially serious adverse outcomes associated with mechanical CPR. Mechanical devices may provide hands-free and uninterrupted CPR, but there are many limitations to its use including cost, training, accessibility and time to implementation of the intervention.

Clinical Bottom Line

There is no statistically significant survival difference between mechanical and manual CPR.

References

1. Rubertsson S, Lindgren E, Smekal D, et. al Mechanical Chest Compressions and Simultaneous Defibrillation vs Conventional Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest: The LINC Randomized Trial. JAMA 2014 Jan 1;311(1):53-61.
2. Perkins GD, Lall R, Quinn T, et. al. PARAMEDIC trial collaborators. Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial. Lancet 2015 Mar 14;385(9972):947-55.
3. Brooks SC, Hassan N, Bigham BL, et. al. Mechanical versus manual chest compressions for cardiac arrest. Cochrane Database Syst Rev. 2014 Feb 27;2:CD007260