Exclusive Interview with Dr WanChun Tang (Part 2)

Per the last interview, Dr Tang had mentioned that, despite the out of hospital (OH) and in hospital (IH) resuscitation team had already done their best, the survival rate is still showing signs of stagnating, leading to reflection.

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The actual efficiency of AED did not reach the anticipation.

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Dr Tang: Most of the cardiac arrest is caused by ventricular fibrillation, therefore early defibrillation is crucial for patients. But most of the time, resuscitation fail because professional defibrillator could not reach the patient in few minutes. The expert then had a new thought of whether, an defibrillator that is foolproof and could be apply by people who doesn’t have any medical knowledge, could be designed? Definitive treatment could then be carry out in short time. The Automated External Defibrillator (AED) is then created.

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In the last 90s, AED was officially widely available, earliest installing in public area that is crowded, and multiple successful case surprised the industry. American Heart Association (AHA) planned to compile a globalized resuscitation guideline, entrusting Dr Weil and Dr Safar, along with fellow experts, to make consensus on resuscitation.

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In the Wolf Creek Conference held in 1996, appointed me and other 10 experts to compile AED chapter for “2000—The First International?Guidelines?Conference on CPR and ECC”, introducing the PAD (Public Access Defibrillator) program. All members of the experts team firmly believe and support that, after publicizing PAD, the resuscitation of cardiac arrest will improve greatly.

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However, 30 years had passed, and the big data shows that: only <12% Out of hospital cardiac arrest (OHCA) patient could have AED reached before EMS, and there are <2% of which ?defibrillation could be done on scene.

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During the 17th?Wolf Creek Conference held in 2023, the editorial board of the PAD program was gathered, and after discussion, we believe that the PAD had failed.

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The main reason could be:

1. Affected by the media, believing that cardiac arrest happens in public area. The big data shows that 70% of OHCA happens at home

2. No standard for where to install AED

3. No continuous maintenance after installing AED

4. User could not find AED immediately

5. Rescuer worry about the legal liability

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After discussion, our expert team believe that:

1. The belief of AED early defibrillation is not wrong, but placing and maintenance should be standardized, making sure AED could be used anywhere in anytime.

2. PAD program should see family and community as key installation point, suggest installing at home

3. Promote basic life support to community, including family doctor, volunteer and couriers

4. Develop wearable, automated moving AED

5. Develop AED map that could link with smartphone and web

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Fulfilling above, AED could play a decisive role in the first instance.

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02

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One Size Fits All might be the reason why survival rate stagnated

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When compiling the guideline, in order to make it easier to remember, the difference between different body type, race and condition were not considered. Instead, identical ?but strict standard: compression depth of 5-6cm, compression rate of 100-120 times/min. But evidently, applying the same compression depth for patient weighting 40Kg and 100Kg is not scientific.

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We made a consensus: One Size Fits All might be the reason why survival rate stagnated.

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Therefore, we suggest the global experts should carry out more clinical research, provide more evidence-based and establish a more scientific resuscitation indicator.

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03

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How do you think about the future?

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Dr Tang:?In fact, chest compression is only a pathway, a bridge, the aim is, before eradicating causes of cardiac arrest, to provide temporary oxygenated blood flow to the body and maintain blood flow of vital organs through effective chest compression, keeping the organs to maintain in a condition of survival. Therefore, the aim of resuscitation should go back to the origin of the disease - rebuilding heart, coronary perfusion pressure and myocardial perfusion.

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1. Should develop and apply non-invasive physiologic vascular study, monitor the change in blood circulation in real life, determine resuscitation strategy, for example, the newest non-invasive carotid monitoring system is a good start.

2. We should be very clear that, CPR by hand is low efficient. Despite every compression is precise, the cardiac output would only be 25% before cardiac arrest, and 10% of perfusion before cardiac arrest. Microcirculation could only be rebuild under the environment of which myocardium receives adequate blood flow; if blood flow is not enough, heart compliance could reduce, and therefore reducing the volume of the heart.

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Therefore, we should encourage resuscitation technology that is more scientific, we should aim for higher coronary perfusion pressure, but not just according to the compression physical standard. The application of MCC-E 3D compression technology. combining cardiac pump and chest pump, is one of the example.

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3. Rectify reversible cause and clogged coronary artery should be treated as soon as possible

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We believe that when a healthy being loss conscious unexpectedly, it’s because of clogged coronary artery. If clogged artery could not be treated in short time, despite using ECMO to re-establish higher blood circulation, the heart muscle would still be under ischemic stage. Even if ROSC is achieved, it does not mean the last survival, the heart might arrest again anytime.

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Among our fellows in Weil Institute, there’s Dr Marko Noc from Slovania. While he was the head of Department of Emergency and Heart, the survival discharge rate of patients having normal neurological function was over 65%!

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The crucial element for such high survival rate is that of his belief: Emphasize on the after care

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His principles of treatment is:

1. All no obvious causes of OHCA, after using Auto CPR Machine, will not procede to on-site resuscitation, but to transfer to the hospital immediately

2. After arriving to the emergency department, whether or not the patient ROSC, enter emergency PCI and treat the clogged coronary artery firstly

3. Combine ECMO and hypothermia treatment according patient’s condition

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Actually not just Dr. Marko, lately in the Cardiac Arrest Center (CAC) constructing standard applied internationally and locally in China, requires an 24/7 PCI. Based on the research, it shows that 96% STEMI and 58% NSTEMI require emergency PCI. Treating the clogged artery will lead to a better recovery.

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SunLife is developing PCI use Auto CPR Machine MCC-T, provide more technological support for emergency PCI.

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Of course, making ECMO portable, apply temperature control during resuscitation is crucial for maintaining a good neurological outcome. That’s why, I suggest that based on the belief of higher blood circulating and myocardial perfusion, is fundamental for improving pulmonary resuscitation.

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Thank you Dr Tang! Developing equipment that is suitable for different resuscitation scene is also one of the direction that, we as medical equipment firm, could work together with medical personnel in order to raise survival rate!

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Thank you for the time, through this interview we have learn so much, we believe that it could also bring inspiration for our resuscitation fellows.

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