Physiology of Cardiopulmonary Resuscitation

Cardiopulmonary Resuscitation (CPR) is the process in which we treat patients in sudden cardiac arrest in the hopes of restoring a pulse but also sufficient blood flow to the heart, brain, and lungs. The process of CPR is to provide chest compressions as well as ventilation for the patient in efforts of regaining a pulse. Though the term CPR was first coined in 1960, resuscitative efforts for patients of cardiac arrest has been constant for hundreds of years with ongoing research in how to best treat these patients for the ultimate chance at survival (History of CPR, 2018). Though this is an ongoing research topic and a practice that is used daily, research shows that post CPR survival rates are still extremely low. Less than 20% of nontraumatic out of hospital cardiac arrest victims survived and less than 40% of in-hospital cardiac arrest victims survived. (Lurie, Nemergut, Yannopoulos, & Sweeney, 2016).

As a prehospital medicine provider, I want the absolute best possible outcome for my patients no matter their complaint. There is no better feeling in the world of feeling a pulse on a sudden cardiac arrest patient and maintaining that pulse. However, while we are happy that we have restored a pulse, many of those patients will not survive much longer and if they do, they will have some sort of neurological deficits. While the process of CPR seems pretty easy, it isn’t. There are countless mistakes that can occur and in turn provide a less poor prognosis for that patient. Simple mistakes can occur easily, for example, during chest compressions the compressor may not have an adequate depth of 5cm or be going to deep or the rate may be too fast or too slow than the recommended 120 compressions/minute (Adult Advanced Cardiovascular Life Support, 2015). The American Heart Association (AHA) recommends this depth with a complete recoil of the chest to provide adequate refilling of the heart as the heart would do itself during a diastole period. Another flaw in CPR is the cessation of compressions for a variety of reasons; for intubation, switch compressors, pulse checks to name a few. With these errors, the oxygenated blood that we are providing is giving adequate perfusion to the brain. When this occurs, it is going to provide a much lower positive neurological outcome for that patient in the event a pulse is regained.

Since CPR has not had a large improvement in survival rates in the last several decades, new studies have shown the Cardiocerebral Resuscitation (CCR) instead of Cardiopulmonary Resuscitation (CPR) is causing much higher rates of survival in out of hospital cardiac arrest victims where their cardiac arrest is presumed cardiac in nature. In CCR, the focus is around providing continuous chest compressions, early defibrillation with early epinephrine administration and establishing comprehensive cardiac arrest centers that can provide specialty care for post cardiac arrest patients (Ewy, Kellum, & Bobrom, 2008). A major difference is noted in CCR is the delay in airway management. The article “Cardiocerebral Resuscitation,” states that because the arterial oxygen level in a patient who has just suffered a sudden cardiac arrest, that patient is not in need of immediate airway management due to their body having a sufficient amount of oxygen still in the bloodstream. The article also notes that the cause for delay in positive pressure ventilation is due to an increase in intrathoracic pressure which decreases venous blood return. The recommended treatment would be to place the patient on a nonrebreather mask with an airway adjunct until a return of circulation was achieved or until several cycles of chest compressions had been completed. With this process, the article noted several agencies having higher success rates than the guidelines provided within the AHA ACLS guidelines (Ewy, Kellum, & Bobrom, 2008).

Despite decades of research worldwide, standard CPR with chest compressions and ventilations still have shown to have a fairly high mortality rate. Recent studies have shown that Cardiocerebral Resuscitation takes on a similar approach to resuscitating cardiac arrest patients and have proven to have higher success rates with minor changes from traditional CPR. As a provider, I hope that more EMS agencies will move to a CCR approach in the hopes of providing our patients with a better outcome with almost all neurological functions intact post cardiac resuscitation.  

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