Timing is Key in Sudden Cardiac Arrest

In the October issue of EMS, we reported on two studies published in the August 12 issue of the New England Journal of Medicine on cardiac arrest, ACLS and public access defibrillation. One study undertaken by Dr. Ian Stiell and colleagues in a well-controlled system in Canada concluded that there is no discernable benefit for patients in cardiac arrest to be treated with ACLS, as opposed to BLS with defibrillation. In order to save lives, said the researchers, citizen CPR and rapid defibrillation need to be a priority.

“It’s very much tied into response time,” says Angelo Salvucci, Jr., MD, FACEP, an emergency physician and medical director for Santa Barbara (CA) County and Ventura County EMS agencies and chair of the California Commission on EMS. “According to the study, there are two important components in the response to cardiac arrest: CPR and defibrillation. What has not been shown to be important is time to advanced care, defined as medications and advanced airway techniques. The time to CPR and defibrillation is what’s important in determining survival following sudden cardiac arrest, not necessarily the provision of ALS. We in EMS need to look at our ultimate objective and, if that is to save lives and discharge people back to their families and the community, we need to do whatever will do that. Nothing in this discussion has anything to do with whether or not ALS is of value to a community, and we know from other work by these same investigators that prehospital ALS care improves outcome in patients with chest pain and breathing emergencies. It has to do with where paramedics are needed; how many are needed; what the expected response time for a paramedic should be; and how to prioritize the importance of different components of an EMS system.”

Concluding that the time to CPR and defibrillation is what determines survival following SCA leads to the second published study on training the public to use defibrillators.

“This is another well-designed, rigorously evaluated study showing that training people to perform CPR and use an AED improved survival from cardiac arrest for two simple reasons: It shortened the time to CPR and shortened the time to defibrillation,” says Salvucci. “After 20 years of evaluation, this concept is as close to a no-brainer as one can get in EMS. We know from every single study in defibrillation that every second longer reduces the likelihood of survival. The brain can’t survive very long when the heart is in ventricular fibrillation, and it’s easier and more effective to defibrillate to a normal rhythm the quicker you do it.”

Using the AED competently is not a no-brainer, however, as some have misleadingly suggested.

“In a frequently misquoted article on untrained sixth-graders being able to use an AED, those sixth-graders were, in fact, not untrained,” says Salvucci. “They were told how to use the pads; told that the ‘victim’ was in cardiac arrest; were working with a manikin, so there was no concern about harming or undressing the person; and the defibrillator was placed in their hands, so they didn’t have to hunt for it. This was a test simply of whether or not they could press the buttons.

“It can’t be generalized that these devices are so simple you just put them on a wall and people will grab them and use them effectively,” Salvucci adds. “There have been numerous articles showing that untrained people make two common mistakes: not peeling the backing off the pads, and putting the pads on over the patient’s clothing. Training is very much necessary, as is follow-up training. Competency declines within three months, and it is important to train and retrain until one is competent and retains that competency.

“I’m hoping that publication of these studies will wake up EMS systems and get them to re-evaluate how they are designed,” says Salvucci. “We have a mountain of evidence that CPR and AEDs benefit people in cardiac arrest, and the sooner they arrive at the patient’s side the better. Where we have very limited evidence is the time value of advanced life support. We know that ALS benefits patients, but whether it has to be there in four or six or eight minutes, or whether 10 or 14 is more appropriate if CPR and defibrillation begin earlier, is what we need to be looking at much more closely. We have spent a tremendous amount of time, effort and healthcare public financing dollars on designing systems that emphasize an eight-minute ALS time, and the medical evidence so far is conclusive that that’s too slow for cardiac arrest. I would encourage EMS systems to re-evaluate that—to examine their priorities and look at how their systems are designed to respond to cardiac arrest and then to all other emergencies.”

—MN