Cardiac arrest remains one of the leading causes of death worldwide. Despite great advances in many other areas of medicine, cardiac arrest treatment has not been able to consistently improve resuscitation outcomes more than traditional cardiopulmonary resuscitation (CPR) with chest compressions and defibrillation.
Here are some novel strategies designed to enhance CPR in cardiac arrest.
- End-Tidal Carbon Dioxide (ETCO₂) and Invasive Arterial Blood Pressure Monitoring
ETCO₂ monitoring during cardiac arrest has gained traction primarily because of its widespread availability and simplicity. ETCO₂ levels indicate the amount of carbon dioxide (CO₂) being exhaled from the lungs, which is directly linked to pulmonary perfusion. If the lungs are getting enough blood flow and oxygen, they can produce CO₂. By monitoring the ETCO₂ during CPR, clinicians can gauge the effectiveness of chest compressions and alter them accordingly in terms of rate, depth, recoil, or hand positioning if ETCO₂ is inadequate. In addition, a declining ETCO₂ post return of spontaneous circulation (ROSC) can signify impending re-arrest.
Invasive arterial blood pressure monitoring is becoming increasingly used during CPR as protocols evolve over time. Gaining arterial access during cardiac arrest can be challenging but has several advantages. The biggest advantage is that it allows immediate recognition of ROSC and can be a proxy for CPR effectiveness. It can also be used to sample blood quickly, helping clinicians to sort out the cause of cardiac arrest, and can even provide a route for endovascular treatments, such as percutaneous coronary intervention.
- Vector Change and Dual Sequential Defibrillation
Defibrillation is the act of stopping the heart by delivering an electrical shock across the myocardium, potentially restoring a normal rhythm. Typically, the pads used for defibrillation are placed anteriorly and laterally on the chest, which is also the direction, or “vector”, of the electrical circuit. Vector change defibrillation, when the pads are instead placed anteriorly and posteriorly on the chest, can adjust the vector and possibly improve defibrillation. A randomized controlled trial (RCT), called DOSE-VF trial, showed that this technique increased survival to hospital discharge compared to standard pad placement.
Dual Sequential Defibrillation (DSED) involves rapid sequential shocks to the myocardium using two defibrillators, delivering a higher total energy to the heart. It combines both standard and vector change pad placements to possibly overcome refractory arrhythmias by disrupting ventricular fibrillation from two different angles. It is more resource-intensive but may be worth considering due to a recent Canadian RCT that showed that survival almost doubled compared to standard defibrillation strategies.
- Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA)
REBOA is widely used in acute trauma care and has recently been proposed as an adjunctive treatment to CPR efforts. This technique involves initially gaining arterial access to the femoral artery in the groin, like the access obtained for arterial blood pressure monitoring mentioned above. A balloon catheter is then advanced through the access point up into the thoracic aorta and inflated. Initially, these balloons had a large profile, close to the size of a pencil, which necessitated surgical cutdown on the artery. Recent advances in technology have miniaturized the balloon catheter down to instead the size of the lead in a pencil. For instance, the COBRA-OS® from Front Line Medical Technologies (London, Ontario, Canada) is the lowest profile device available and can be deployed in just over a minute. These technological advances have allowed REBOA to be considered in pre-hospital environments by less skilled operators and is even being seen as a bridge to more advanced treatment options, such as extracorporeal cardiopulmonary resuscitation (discussed in the next section).
For cardiac arrest, REBOA works by increasing coronary perfusion pressure (more oxygenated blood to the myocardium) which gives the heart a better chance of gaining back a normal rhythm. During routine chest compressions without aortic occlusion, blood circulates to the whole body. REBOA short-circuits this pathway, allowing increased perfusion to the heart and brain. This not only may increase the rates of ROSC but may ultimately improve neurological outcomes in cardiac arrest, which are known to be poor. A multicenter RCT is currently underway in Norway exploring whether REBOA can improve ROSC rates and survival, with another trial beginning to recruit in Japan later this year.
- Extracorporeal Cardiopulmonary Resuscitation (ECPR)
ECPR is a method of cardiopulmonary resuscitation that removes a patient’s blood, oxygenates it, and pumps it back to perfuse all vital organs. In other words, it completely bypasses the heart and lungs and negates the need for chest compressions and defibrillation. This technique is the most complicated and resource-intensive strategy currently being considered to improve outcomes in cardiac arrest but many groups around the world have been able to deploy this even in the prehospital environment to improve patient outcomes.
Beyond traditional approaches to cardiac arrest, improved patient monitoring, defibrillation strategies, and more invasive adjuncts, such as REBOA and ECPR, hold incredible promise. By combining research, education, and technology, we can continue to improve outcomes for patients facing this critical condition. Every second counts in cardiac arrest, and our collective efforts can make a significant impact on survival rates.
About Adam Power
Dr. Adam Power serves as the Co-Founder and Chief Medical Officer of Front Line Medical Technologies Inc., a leader in innovative medical devices for trauma and emergency care that is committed to lowering the barriers in bleeding control and resuscitation. Dr. Power was instrumental in the development of COBRA-OS®, drawing on his unique clinical viewpoint and expertise to ensure utmost patient safety and assist with the company’s global expansion. In this role, Dr. Power is able to use his passion for medical device innovation in his relentless pursuit to help critical patients survive.
