Measuring CPR Quality

The American Heart Association reported the results of a study in their quinquennial update in which cameras were placed in various emergency rooms, revealing that CPR was typically only performed between twenty-five and fifty percent of the time during cardiac arrest resuscitations. 

The reason was not for lack of effort or caring—just a lack of adherence to standards. We all do whatever we think is important. What anyone might think is important is of course highly subjective and is typically based on anecdotal experience and personal preference. This reality is the reason why standards, created from evidence-based medicine, are so important.

Until the last decade, advanced cardiac life support, by its very name, implied an inherent importance over basic life support. For years, IV access, drug administration and the king of all resuscitation interventions—the intubation—were perceived as being the most important treatments in resuscitation. Technology is amazing, but for all its value and promise, it comes with a downside of which any practitioner must be aware: it draws attention away from the patient and often, away from simpler but more effective interventions.

Research has proven that the benefit of all advanced life support interventions in cardiac arrest are more theoretical than actual. In fact, no one has yet proven that anything other than CPR and early defibrillation for adults, and CPR with an increased emphasis on ventilation for pediatric patients, is effective in resuscitation of cardiac arrest.

Yet as critically important as CPR is in the treatment of cardiac arrest, we’ve been flying blind as far as its efficacy, until now. Technology is now available to measure the performance of CPR in all of its component parts and in real time.

As a testament to their commitment to ever-improving patient care, Central Bucks Ambulance in Doylestown, Pa. recently added a CPRmeter to each of their basic and advanced life support ambulances.

Central Bucks Ambulance selected the CPRmeter by Laerdal due to the fact that it could be used standalone, without needing to be tethered to a cardiac monitor. This was important for Central Bucks Ambulance since they provide basic life support services and do not carry cardiac monitors.

Representatives from Laerdal recently came out to Central Bucks Ambulance to demonstrate the CPRmeter. This was the author’s first exposure to a CPR quality measuring device as well, and it was impressive.

Laerdal representative Bob Reedy says, “If you do not measure something you cannot improve upon it.” He then proceeded to prove his case.

Everyone got a chance to perform CPR blindly as we’ve been doing all these years, but with the quality of our compressions being recorded by a recording manikin. The results showed widely varying degrees of effectiveness. One of the more petite providers scored a 43%. That provider was then handed the CPRmeter and asked to try again. With the benefit of real time feedback provided by the CPRmeter, the provider instantly improved her performance to 97%.

While CPR may be considered basic, it is anything but simple when you break it down. Effective CPR as defined by the AHA is a combination of minimal interruptions, appropriate chest compression depth of at least two inches for adults and one third of the anterior posterior diameter for children, a compression rate of between one hundred and one hundred twenty per minute and allowing for full chest recoil.

Minimal interruption is important because it’s been proven to take several compressions to build up to the maximum coronary perfusion pressure (CPP), which even with the best CPR is still only one quarter to one third of the normal CPP. But, since CPR is only meant to keep the vital organs of the heart, brain and lungs minimally perfused while a reversible cause is identified and corrected, one quarter to one third is good enough—for a while.

Depth and rate of compression are important because they are directly related to the maximum amount of blood flow that can be achieved by CPR. Full recoil is important because as it turns out, most of the blood flow created by CPR actually takes place during chest recoil and not during the down stroke as we all thought for so many years. It is also during this period of diastole that coronary blood flow takes place, which of course is a critical function in perfusing the myocardium.

CPR quality measuring devices have sensors connected to a screen, which provides immediate visual feedback on compression depth and rate. They also record a downloadable summary of all CPR for the entire duration of the event for retrospective review.

CPR is now recognized as the key intervention for cardiac arrest, and flying blind with regard to the efficacy of CPR is no longer acceptable. Technology now not only offers CPR quality measurement, but also offers real-time performance feedback, allowing for immediate correction of deficiencies and the greatest possibility for better outcomes.

Joe Hayes, NREMT-P, is deputy chief of the Bucks County Rescue Squad in Bristol, PA, and a staff medic at Central Bucks Ambulance in Doylestown. He is the quality improvement coordinator for both of these midsize third-service agencies in northeastern Pennsylvania. He has 30 years' experience in EMS. Contact Joe at jhayes763@yahoo.com.