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Evidence-Based EMS: Automated Chest Compression Devices
It was a typical night for Michael Snyder, Jr. as he settled into his third-floor apartment with a few friends. Little did he know that later that evening, he would succumb to a cardiac arrest. When it happened his friends immediately called 9-1-1. Within minutes of EMS’ arrival, paramedics realized performing hands-on CPR would hinder Michael’s removal. The only way to maintain uninterrupted CPR while moving him from his third-floor walkup to the ambulance would be with mechanical help.
Fortunately Michael’s local EMS system had the foresight to equip every paramedic unit with an automatic chest compression device (ACCD). The paramedics applied the ACCD and transported him down three flights of stairs. Their ACCD performed its lifesaving intervention throughout and during the entire transport to the hospital.
To the credit of the paramedics for their quick thinking, the EMS system’s progressive planning and investment in technology, and the ACCD, Michael Snyder, Jr. survived without any neurologic deficits. But beyond a unique case like this, does the evidence demonstrate a true benefit to ACCDs with cardiac arrest victims on a larger scale? Are they worth the investment?
Automated Chest Compression Devices (ACCDs)
Good chest compressions remain an integral part of the resuscitation of a pulseless patient, but challenges frequently interrupt or compromise their quality. This is especially true in the prehospital setting, where personnel may be limited and other critical procedures such as airway management, intravenous access, medication administration and transport may compete with good compressions. In addition, rescuer fatigue can often set in well before arrival at a hospital.1
In principle, a device that delivers automated chest compressions could reduce interruptions, ensure appropriate depth and frequency, and free up personnel and space to perform other tasks. But should they be implemented universally? A number of questions need to be addressed before coming to a conclusion.
Are ACCDs safe and reliable?
One of the issues with using an automated device is the potential for injury to the patient. Trauma such as rib fractures and pneumothoraces are known complications from manual CPR, but there are no studies comparing the incidence of these complications between manual and automated CPR. However, cardiac arrest survivors will regularly testify that they would rather be alive with a broken rib than dead and uninjured. Additionally, for extremely obese patients, an ACCD may not be able to accommodate their large chest circumference, though devices are rated for weight and providers are trained to understand the uses and limitations of the devices prior to deployment. Reliability has been integral to the implementation of ACCDs, and there is one notable case report where an ACCD was placed on a hypothermic drowning patient for 5 hours and 20 minutes, allowing initiation of cardiopulmonary bypass.2
When should ACCDs be used?
Another clear advantage of using an ACCD is the ability to provide prolonged periods of effective chest compressions without concern for provider fatigue as well as freeing up personnel to perform other important tasks. With use of ACCDs, compressions do not stop when the patient is being transported to a stretcher, into an ambulance, out of the ambulance or to the receiving hospital stretcher. One case study in 2011 documented a patient with a suspected splenic hemorrhage who went immediately to the OR, where he arrested. He was placed on an ACCD for 40 minutes before return of spontaneous circulation (ROSC), which allowed for source control with a splenectomy and recovery without neurologic deficits.3
In addition to maintaining circulation in the pulseless patient with an extended period of prehospital transfer, ACCDs, once integrated as part of the community’s EMS CPR chain of survival, free up first responders and EMS providers to perform other critical procedures, an obvious benefit. Additionally, there is new evidence to suggest that performing chest compressions while the patient is placed in a 30-degree reverse Trendelenburg position may improve outcomes [www.emsworld.com/12088616]. The only effective way to deliver such an intervention with effective compressions is via an ACCD and an elevated backboard.
Will an ACCD hinder resuscitation while it’s getting set up or in use?
Deploying an ACCD on a patient will invariably cause a pause in manual chest compressions, but in reality this time is minimal, especially given that providers are trained to seamlessly integrate the device into their resuscitation with a “pit crew” approach. A study looking at a load-distributing band CPR device found that providers could reliably deploy the device in under 60 seconds.4
Once the device is in place, there will be additional room around the patient where the provider performing chest compressions would have been. In simulations, having an ACCD in place and operating does increase the time needed for intubation, but by less than 10 seconds.5 Percutaneous coronary intervention can even be performed while an ACCD is in place, as demonstrated by a 2014 Journal of Emergency Medicine case report in which the patient achieved ROSC after the procedure.6 With the continued evolution of newer devices, rhythm analysis and shock delivery will be possible in the future, further augmenting resuscitative efficiency.
Do ACCDs improve patient outcomes?
Currently there is no robust data to support that ACCDs improve measurable patient outcomes in prehospital cardiac arrest. This is despite the fact that ACCDs have been shown to increase mean systolic and diastolic pressure in patients compared to manual chest compressions.1 A randomized multicenter trial consisting of 767 patients demonstrated that use of an ACCD resulted in a delay of two minutes to defibrillation, and survival to hospital discharge in the ACCD group was 5.8%, compared to 9.9% in the manual CPR group (p=0.04). In addition, Cerebral Performance Category (CPC) scores were higher in the manual CPR group. This data suggests the use of an ACCD results in worse patient outcomes.7
However, a later study with 1,011 patients found that in the emergency department setting, implementation of an ACCD showed a trend toward better survival to discharge and neurologic outcome.8 A more recent review in 2012 found insufficient evidence to support or refute the use of ACCDs in out-of-hospital cardiac arrests, and while ACCDs provide more consistent compressions, they may in fact worsen neurologic outcome.9
Bottom Line: Worth the Cost?
ACCDs can easily cost over $10,000 for a single unit, and disposable components for the units (e.g., straps, suction cups) must be purchased separately. One available ACCD has a listed price of $14,495.10 To equip an EMS system with these devices on every ambulance could be cost-prohibitive, and for this reason ACCDs may not be ready for widespread implementation in prehospital care. However, each system must also weigh the cost of an ACCD against the importance of freeing up personnel to perform other important tasks. Finally, given the few case reports of positive outcomes, there may be an important role for ACCDs in select patients.
References
1. Duchateau FX, Gueye P, Curac S, et al. Effect of the AutoPulse automated band chest compression device on hemodynamics in out-of-hospital cardiac arrest resuscitation. Intensive Care Med, 2010 Jul; 36(7): 1,256–60.
2. Michalski T, Gottardi R, Dunser MW. Extensive soft tissue trauma due to prolonged cardiopulmonary resuscitation using an automated chest compression (ACC) device. Emerg Med J, 2014 May; 31(5): 431.
3. Dumans-Nizard V, Fischler M. Intraoperative use of an automated chest compression device. Anesthsiology, 2011 May; 114(5): 1,253–5.
4. Ong ME, Annathurai A, Shahidah A, et al. Cardiopulmonary resuscitation interruptions with use of a load-distributing band device during emergency department cardiac arrest. Ann Emerg Med, 2010 Sep; 56(3): 233–41.
5. Agostinucci JM, Catineau J, Jabre P, et al. Impact of the use of an automated chest-compression device on airway management during out-of-hospital cardiopulmonary resuscitation: the PLAINT study. Resuscitation, 2011 Oct; 82(10): 1,328–31.
6. Forti A, Zilio G, Zanatta P, et al. Full recovery after prolonged cardiac arrest and resuscitation with mechanical chest compression device during helicopter transportation and percutaneous coronary intervention. J Emerg Med, 2014 Dec; 47(6): 632–4.
7. Hallstrom A, Rea TD, Sayre MR, et al. Manual chest compression vs use of an automated chest compression device during resuscitation following out-of-hospital cardiac arrest: a randomized trial. JAMA, 2006 Jun 14; 295(22): 2,620–8.
8. Hock Ong ME, Fook-Chong S, Annathurai A, et al. Improved neurologically intact survival with the use of an automated, load-distributing band chest compression device for cardiac arrest presenting to the emergency department. Crit Care, 2012 Aug 3; 16(4): R144.
9. Ong ME, Mackey KE, Zhang ZC, et al. Mechanical CPR devices compared to manual CPR during out-of-hospital cardiac arrest and ambulance transport: a systematic review. Scand J Trauma Resusc Emerg Med, 2012 Jun 18; 20: 39.
10. Medical Device Depot. LUCAS 2 Chest Compression System, https://www.medicaldevicedepot.com/LUCAS-2-Chest-Compression-System-p/99576-000011.htm.
