Man v Machine

A few volunteer medic units around Baltimore County have purchased mechanical chest compression devices.  There are two types of mechanical devices available: load-distributing band CPR devices (LDB-CPR) and piston-driven CPR devices (PD-CPR).

Example of LDB-CPR device: AutoPulse (Zoll Medical Corporation)

Example of PD-CPR device: LUCAS (Physio-Control Inc.)   

Manual CPR - the old fashion way - using you hands - is denoted by the abbreviation M-CPR.

Station 500 Chestnut Ridge Volunteer Fire Company has had a LUCAS device in-service aboard Medic 505 for over a year (pictured below).  If Engine 501 first responds to a potential or actual cardiac arrest for a career medic unit - the engine crew grabs the LUCAS device as they roll out the door.  The device rapidly and easily clips onto a small board placed behind the patient's back, has velcro straps to secure the patient's hands, and can be easily loaded with the patient onto a backboard or Reeves stretcher.  Mechanical compressions can be started and stopped with the push of a button.  The device is light-weight and battery powered.  The rechargeable lithium-ion battery can run about 45 minutes.  A spare battery is usually packaged with the device.  When not in use, the LUCAS charges on a shelf in the medic unit.  Specs for this device can be found on Physio Control's website.

Mechanical CPR (LDB-CPR and PD-CPR) devices provide the following benefits:

• More effective and consistent CPR (consistent rate, depth, position)
• Machines do not fatigue
• More consistent compression recoil (upstroke phase of chest compression cycle)
• Defibrillation can be performed without stopping mechanical chest compressions
• Reduce risk of injury to EMS providers during transport to the hospital (i.e. no standing in the back of the medic unit responding priority 1 to the hospital)

High quality CPR is the catch phrase of the year in EMS systems around the US and something that our EMS leadership in Baltimore County is keenly interested in seeing become the standard of care.  

The fundamental concept of high quality CPR is uninterrupted, proper rate and depth compressions with little to no pause immediately before and after shocks and around pulse/rhythm checks.  Other skills during the course of resuscitation like intubation and IV insertion should ideally be performed without any interruption in the delivery of compressions.

This month in the journal Critical Care Medicine, Westfall et al published a study entitled, "Mechanical Versus Manual Chest Compressions in Out-of-Hospital Cardiac Arrest: A Meta-Analysis".  The study looked at the likelihood of obtaining return of spontaneous circulation (ROSC) in patients treated with manual compressions compared to those treated with mechanical CPR.  A total of 12 studies comprising of 6,538 subjects with 1,824 ROSC events were included in the analysis.

It is important to note that ALL of the four authors of this study either work for, consult for, or have received grants from Zoll (manufacturer of the AutoPulse).

When manual (M-CPR) compressions were compared with BOTH types of mechanical devices (LDB-CPR + PD-CPR devices) there was a significantly increased odds of ROSC when using mechanical CPR devices.  The odds of ROSC were significantly better (in this meta analysis) with LDB-CPR type devices (like the AutoPulse) as compared to the PD-CPR type mechanical devices (like the LUCAS).

There is NO analysis of neurologic outcomes in this study.  Furthermore, the authors conclude that these findings need to be validated in larger randomized controlled clinical trials.

The bottom line - mechanical devices cost money.  The money trees remain elusive.  It would be nice to see these devices on all eight of our DO vehicles.  In this man v machine meta analysis - machine wins.

But we humans can strive to be high quality CPR machines!

We need to focus our efforts on learning and rapidly implementing high quality manual CPR.  Members of Baltimore County's EMS Division recently attended a Resuscitation Academy at the Howard County Fire Rescue Academy jointly sponsored by Seattle Medic One.  This two day conference focused on every aspect of high quality CPR from dispatch directed CPR, to the actual performance of the resuscitation by EMS providers, to data collection, and even touched on caring for the patient's family during and after the arrest.  

Please look for more information on how Baltimore County Fire Department is implementing these high quality CPR initiatives in the next few weeks and months.