EMS Insider, Research Alert

Penn Study on Mechanical and Manual CPR with EMS Insider Highlights

News release via Penn Medicine — Mechanical CPR, in which a device is used by Emergency Medical Service (EMS) providers to deliver automated chest compressions during cardiac arrest resuscitation care, is associated with an equivalent survival rate for patients experiencing cardiac arrest outside of the hospital as manual CPR, according to new findings from a team of researchers at the Perelman School of Medicine at the University of Pennsylvania. The study is the first large scale, real-world proof that mechanical CPR may be an equivalent alternative to manual CPR for treating patients experiencing extensive cardiac arrest episodes and requiring advanced life support services. The results are being presented during the American Heart Association Scientific Sessions.

Previous research has questioned the effectiveness of mechanical CPR, citing concerns about costs, and the time it takes to apply the device. Other studies have suggested that while there is some low-quality evidence showing that mechanical CPR can improve consistency of chest compressions, evidence showing the effect on survival rates and neurological outcomes is lacking.

“The takeaway here is that these devices may very well be a useful alternative to manual CPR for patients who may be in need of advanced life support,” said the study’s corresponding author Benjamin S. Abella, MD, MPhil, an associate professor of Emergency Medicine and clinical research director of the Center for Resuscitation Science at Penn Medicine. “This information holds important possibilities for EMS providers who may be located in a rural area, or whose patients may be in transit to a hospital for an extended period of time due to traffic or other conditions. Patients who have extended cardiac arrest duration likely need proper administration of CPR for a longer time, which is where the mechanical devices may play a role, as they remove the element of human error and fatigue.

In the study, researchers analyzed more than 10,000 cardiac arrest cases outside of a hospital, of which 18% received mechanical CPR from an EMS provider, and 81% received manual CPR. Overall, manual CPR was associated with better outcomes overall. However, the researchers suspected the information was skewed based on the fact that good outcomes are more likely in cases where a pulse is regained quickly. In most of these cases, mechanical CPR would not be available or necessary. After accounting for the amount of time the patient experienced the cardiac episode and removed incidents where the patient regained a pulse quickly, the results showed that patients who received mechanical CPR were 8% more likely to regain a pulse than those who received manual CPR.

“In recent years, proper administration of CPR has become an important focus of successful resuscitation, leading many EMS agencies to adopt mechanical CPR devices in an effort to provide consistent compressions while transporting cardiac arrest patients to hospitals,” Abella said. “Now that we know the survival rates are equivalent for mechanical CPR and that the EMS providers aren’t causing harm to these patients, we can start designing more advanced studies that take other characteristics of cardiac arrest into account.”

Study authors suggest further research is necessary to fully realize the effectiveness of mechanical CPR and factors associated with its survival rate

JEMS and EMS Insider editor-inchief A.J. Heightman comments — Long a proponent of mechanical CPR, I believe this University of Pennsylvania Study is important for several reasons: 1. The study of 10,000 out-of-hospital cardiac arrest cases is the first largescale, real-world proof that mechanical CPR may be an equivalent alternative to manual CPR for treating patients experiencing extensive cardiac arrest episodes and requiring advanced life support services.

2. The study, being presented during the American Heart Association Scientific Sessions, acknowledges that, “Mechanical CPR…is associated with an equivalent survival rate for patients experiencing cardiac arrest outside of the hospital as manual CPR.”

3. The study’s highly respected corresponding author and cardiac arrest researcher Benjamin Abella, MD, MPhil, an associate professor of Emergency Medicine and clinical research director of the Center for Resuscitation Science at Penn Medicine, acknowledges that mechanical CPR devices, “may very well be a useful alternative to manual CPR for patients who may be in need of advanced life support.”

4. The study separated out cases of early CPR in which a pulse was regained quickly. This is important because, while some studies have reported that manual CPR was associated with better outcomes overall, the researchers suspected this information was skewed based on the fact that good outcomes are more likely in cases where a pulse is regained quickly. The researchers realized that extended CPR times, inconsistency in provider time-on-chest and effectiveness, prolonged transport times, impediments to continuous compressions such as patient movement down stairways and into an ambulance, as well as loading and transportation of patients in a moving ambulance, are all valid indications for mechanical CPR and may well be the reason for improved resuscitation results in EMS systems that used the mechanical compression devices.

5. The study notes, “After accounting for the amount of time the patient experienced the cardiac episode and removing incidents where the patient regained a pulse quickly, the results showed that patients who received mechanical CPR were 8% more likely to regain a pulse than those who received manual CPR.”

6. Dr. Abella notes that, “This information holds important possibilities for EMS providers who may be located in a rural area, or whose patients may be in transit to a hospital for an extended period of time due to traffic or other conditions. Patients who have extended cardiac arrest duration likely need proper administration of CPR for a longer time, which is where the mechanical devices may play a role, as they remove the element of human error and fatigue.”

7. Dr. Abella further states, “In recent years, proper administration of CPR has become an important focus of successful resuscitation, leading many EMS agencies to adopt mechanical CPR devices in an effort to provide consistent compressions while transporting cardiac arrest patients to hospitals. Now that we know the survival rates are equivalent for mechanical CPR and that the EMS providers aren’t causing harm to these patients, we can start designing more advanced studies that take other characteristics of cardiac arrest into account.”

In the 2015 AHA Guidelines, while pointing out that manual chest compressions remain the standard of care for treatment of cardiac arrest, the AHA acknowledges that “mechanical chest compression devices may be a reasonable alternative for use by properly trained personnel. The use of the mechanical chest compression devices may be considered in specific settings where the delivery of high-quality manual compressions may be challenging or dangerous for the provider (e.g., prolonged CPR during hypothermic cardiac arrest, CPR in a moving ambulance, CPR in the angiography suite, CPR during preparation for ECPR), provided that rescuers strictly limit interruptions in CPR during deployment and removal of the device.” (The devices are now listed as Class IIb, LOE C-EO).

To see the impact mechanical CPR can have on improved resuscitation of patients who require extended time of compression performance from scene to hospital and continuing into the Cardiac Catherization Lab, see the article in the December 2015 issue of JEMS (our Emergency Cardiac Care Update—Conference Issue): “It Takes a Village to Save a Life: How Centre LifeLink EMS increased cardiac arrest survival rate in State College, Pa., from 4% to 20%.”