EMS Magazine`s Resource Guide: Cardiac Care

Women and Heart Disease

After years of doing heart disease research only on men, the medical community has finally realized that women and men experience heart attacks very differently. This new information has come as a big surprise, especially to women.

“Until 1996, research was focused on men and heart disease, with the exception of one study on 3,000 nurses,” says Dawn Bidwell, coordinator for the Alexandria (MN) Division of North Memorial EMS Education. “It’s only been in the last year or two that research has come out showing that women do, indeed, have different symptoms than men. Women have smaller vessels, fewer vessels and more flexible vessels, and they have a whole different approach to heart disease than men do.”

As a result, says Bidwell, women have largely ignored their unusual symptoms, as have their doctors and EMS providers. “This accounts for the fact that women have a 50% higher chance of having a prehospital cardiac arrest than men,” she adds.

So what are these unique symptoms? Unusual fatigue—becoming exhausted just walking across a room; new and unusual shortness of breath during everyday activities, particularly those that require use of the upper arms or upper body like brushing the hair, vacuuming or other daily chores; nausea and dizziness, which are often ignored because there is no chest pain to go with them; and lower back pain without any history of back pain or trauma.

“Now that the information is out, we’re trying to educate EMS providers to not ignore those symptoms in women,” says Bidwell. “To go even further and ask about their history: Do they have a history of smoking? Do they have a history of using oral contraceptives? Is there a history of heart attacks in the females in their family? If so, put them on oxygen and treat them as though they’re having a heart attack, hoping that’s not what it is. Some paramedics are being given permission to do a 12-lead in the field to see if there are any changes. It never hurts to overtreat a patient.”

Now that the research is out, there has been a dramatic increase in the amount of information available. The American Heart Association, in particular, has done an excellent job of getting out pamphlets and special projects to promote these new findings, says Bidwell. For more information, visit www.americanheart.org.

AEDs in the Public Square: The Price is Right

An estimated 250,000 Americans die each year from cardiac arrest suffered at public places such as malls, sports stadiums and airports. The American Heart Association (AHA) recommends that AEDs be located in public places where there is a chance of using them once in five years, or a 20% annual probability. However, according to a study supported by the Agency for Healthcare Research and Quality (AHRQ), AEDs could be deployed at sites with only a 12% annual probability of use and still be cost-effective.

Peter Cram, MD, MBA, of the University of Iowa College of Medicine, and his colleagues compared two strategies at selected public locations in the U.S. In the first strategy, individuals experiencing cardiac arrest were treated only by EMS personnel equipped with AEDs (EMS-D). In the second, individuals were treated with AEDs deployed as part of a public access defibrillation (PAD) program. Strategies differed only in how fast an AED could be deployed and the impact of time on cardiac arrest survival.

Under Strategy 1, cardiac arrest victims had a 10% probability of survival to hospital discharge. Under Strategy 2, survivability jumped to 25% (based on an average response interval of 4.5 minutes).

Under the base-case assumption that a deployed AED will be used on one cardiac arrest every five years, the cost per quality-adjusted life year (QALY) gained was $30,000 for AED deployment ($3,400 per site per year) when compared with EMS-D intervention, and still less than $50,000 per QALY gained (considered cost-effective for medical intervention) when the annual probability of AED use was less than once in eight years.

Researchers concluded that the AHA recommendations might be conservative and, “limited expansion of PAD programs can be justified on clinical and economic grounds,” but noted also that the “cost-effectiveness of AED deployment strongly depended on the benefits of EMS-D. In many public locations with low cardiac-arrest rates, encouraging the optimization of existing EMS may represent a more efficient solution.”

• Cram P, Vijan S, Fendrick AM. Cost-effectiveness of automated external defibrillator deployment in selected public locations. J Gen Intern Med 18(9):745–754, Sep 2003. Information from www.ahrq.gov

Emerging Cardiac Consensus: Give That Patient a Balloon

New guidelines from the American Heart Association and American College of Cardiology issued in June reinforce the importance of fast treatment when chest pain develops. The guidelines—published in the June 15 Circulation and the June 21 Journal of the American College of Cardiology and available at both www.americanheart.org and www.acc.org—also detail the best way for physicians to manage patients with ST-elevation myocardial infarction (STEMI), a type of heart attack in which a coronary artery is completely blocked. Fast treatment is required because heart muscle is lost with every minute treatment is delayed. If blood flow is not restored within 20 minutes, permanent damage will occur.

Just what that treatment should be, however, may be evolving. Typically, most jurisdictions treat such heart attacks with thrombolytics, clot-busting drugs that break up the arterial obstruction. A newer school of thought, though—backed by a growing body of evidence and literature—holds that STEMI patients are better served by primary angioplasty, or the use of a stent and a balloon to break up the blockage in the hospital.

“The survival rate is similar between angioplasty and thrombolytics,” says Robert O’Connor, MD, MPH, FACEP, chair of the AHA’s subcommittee on advanced cardiac life support, “but you get fewer complications with angioplasty, and the reinfarction rate is lower.”

The downside is that angioplasty relies on quickly getting STEMI patients to a facility that can perform the treatment. Not all hospitals can. Generally, primary angioplasty is only available at hospitals with top-notch cardiac centers that include catheterization labs. Presently, only about a third of heart attacks in the U.S. are treated this way, though an estimated four-fifths of the U.S. population lives within an hour’s drive of an angioplasty center.

“It takes a highly trained, highly experienced staff to be successful with angioplasty,” says O’Connor, “so while it’s fairly widely available, it’s not universal.”

The survival rates are indeed similar: Mortality rates, drawn from nearly two dozen relevant studies, are around 7% for STEMI patients receiving primary angioplasty and 9% for those getting thrombolytics. Stroke rates are 1% and 2%, respectively. But the recurrence rate is 3% for angioplasty patients and 7% for those receiving clot-busters.

In the new guidelines, the clot-busters vs. angioplasty decision is based on four factors:

• How much time has passed since the onset of symptoms?
• How great is the risk of dying?
• How great is the risk of bleeding in the brain if clot-busting drugs are used?
• How much time will it realistically take to get the patient to a cardiac catheterization lab for stenting?

That last bit is the tricky part. In some jurisdictions, EMS crews, having diagnosed the STEMI in the field (available literature strongly suggests that paramedics can accurately identify ST elevation via 12-lead EKGs), can take patients directly to hospitals with cath labs, even if they’re not the closest facility. In others, patients are turned around quickly at hospitals without angioplasty capability and moved on to hospitals that have it.

In the latter case, time is the key. A recent study from Denmark shows better outcomes for such patients, but another from the University of Michigan suggests any advantages disappear if the treatment is delayed more than 90 minutes.

Thus, time is the main factor EMS systems must consider when determining protocols for STEMI patients.

“It’s largely a matter of the medical director and other decision-makers assessing their local situations to see what sort of resources are available, and then tailoring their protocols to the local resources,” says O’Connor. “If you could take patients who are identified as having an MI in the field to an angioplasty-capable center, that may be preferable. However, in other situations, that may mean a time delay that would warrant them going to the closest hospital to get thrombolytics or arrange secondary transfer instead. It’s a matter of timing.”

Secondary issues, of course, include medics having 12-lead field EKG capability, and potentially longer out-of-service times if ambulances take patients to more-distant angioplasty-capable hospitals. And from the hospital side, cath labs are expensive, and heart attacks are, quite frankly, profitable.

“There is no incentive to change,” Cindy Grines, MD, of William Beaumont Hospital in Detroit, a key angioplasty researcher, told CNN for a story in 2003. “The small hospitals don’t want to divert patients to larger hospitals, because that’s lost revenue.”

STEMIs are estimated to represent roughly 5% or less of MIs diagnosed by paramedics using 12-lead in the field. Half a million Americans suffer them every year.

Pediatric Arrests Take ’Em or Leave ’Em?

Emotions run high when EMS personnel are faced with stopping resuscitation of a child—emotions that can impact how you manage the patient, the scene and yourselves. Fortunately, researchers are finally publishing data that address the issue of when a resuscitation effort is futile and it’s time to stop.

“There’s currently a collision between the science that tells us when our attempts are futile, and the art, which is the difficulty for EMS providers to stop giving everything they’ve got for a kid,” says Ed Racht, MD, medical director for Austin/Travis County EMS System in Austin, TX. “There are so many emotional and cultural implications of child death outside the hospital: parental support, crime scene issues, forensics, whether it’s a case of child abuse, and organ and tissue donation. Data show that emergency providers are much more likely to extend the time for resuscitative efforts in children than in adults, even though the futility data in both populations are similar. We develop an emotional relationship that makes it harder to stop, because our tool kit in emergency medicine is action.”

One topic currently under discussion is whether the practice of transporting a child with no return of spontaneous circulation to the ED to continue resuscitation instills in parents a sense that everything was done or instills a roller-coaster of emotion that may evoke false hope, says Racht.

“A lot of nursing literature is starting to look at the issue of parental presence during resuscitation,” he says. “Rescuers often say, ‘Why don’t you wait out here while we do what we need to do,’ or ‘Why don’t you ride up front in the ambulance while we take care of your child?’ when the parent may need to ride back there, as hard as that is. Even if the child doesn’t survive, it may actually be better for the parents to be there than to isolate them. For us, of course, it’s easier to perform without the parents present. The emotional impact of glancing at an anxious parent on a rescuer is huge, so there’s some benefit of not having that emotional distraction there.”

Racht recommends the following sources of current data on the issue of out-of-hospital pediatric resuscitation:

• Resuscitation 60(2):175–187, Feb. 2004.
• Pediatrics 114(1):157–164, Jul. 2004.
• N Engl J Med 335(20):1473–1479, 1996.

Mechanical Chest Compression Device Gains Ground in EMS Market

In the October 2002 issue of EMS Magazine, editorial advisory board member Matthew Streger, MPA, NREMT-P, said about the AutoPulse Resuscitation System: “This could be one of the first changes in cardiac arrest management to actually affect patient survival.” Since that time, several new developments have taken place, including the AutoPulse Assisted Prehospital International Resuscitation (ASPIRE) Trial to evaluate the safety and effectiveness of AutoPulse, developed by Revivant Corp. of Sunnyvale, CA. As part of the international study, researchers in the Department of Emergency Medicine at the University of Pittsburgh (PA) School of Medicine will test the effectiveness of the mechanical chest compression device to see if it does a better job than manual chest compressions for the treatment of out-of-hospital sudden cardiac arrest.

The FDA-approved, portable external device is designed to provide consistent automated chest compression cycles during CPR to produce a palpable pulse.

University of Pittsburgh researchers will work with seven local EMS agencies to train paramedics on how to use the AutoPulse. During the one-year study, half of patients will receive manual chest compressions and the other half will receive compressions with the AutoPulse. Patients who survive and agree to continue to participate in the study will be followed for three months after the event.

Other cities participating in the ASPIRE Trial include Seattle, WA; Calgary, Alberta; Vancouver, BC; and Columbus, OH. With all centers combined, researchers hope to enroll 1,300 patients.

The AutoPulse is not being used exclusively by researchers, however. In Downers Grove, IL, fundraising efforts by a concerned citizen netted three of the devices for the Downers Grove Fire Department.

“My wife and I were watching the local news in early May, when a vignette about this new medical device for resuscitation caught our attention,” says Downers Grove realtor George Nicholaou. “The next day, I asked the fire department and mayor about how much they cost, and made some inquiries to the state about how to create a nonprofit organization. It struck me that out of a community of 56,000 people, we should be able to raise $42,000 in a relatively brief period of time.”

That’s when Nicholaou got on the phone and began calling everyone he knew, from his plumber and chimney cleaner to local hospitals and car dealerships. Linda Kunze, manager of the Downtown Management Corp., supplied names and made calls in her spare time.

“By being tenacious and calling five to six hours a day, we raised $47,000 in about 45 days,” says Nicholaou. “I knew it could be done, and rather than ask ‘why,’ it was more rewarding to ask ‘why not?’”

To date, the fire department has not had occasion to use the devices, but the peace of mind that comes from knowing they are available if needed makes it all worthwhile, he says.

“We raised $5,400 more than we needed, which will allow us to buy a year’s worth of disposable wraps,” Nicholaou adds. “The intent in our town is that the first 50 or so people who need the AutoPulse will obviously be charged for the ambulance but will not be charged for the wrap. We already have an excellent paramedic department, and this makes it even more state of the art.”

An EMS system where AutoPulse has been used is Collier County EMS in Naples, FL. Although they have only had the device for four months, Steve Donovan, EMT-P/FF, used it on a cardiac arrest patient early on.

“What I really like about it is, in addition to giving effective compressions and freeing up personnel to do other tasks, it helped me establish an IV line,” says Donovan. “Patients in cardiac arrest are usually in venous collapse, and after using AutoPulse for just a couple of minutes, it pushed enough blood around to let the veins pop up.”

The device has its own carrying case and resembles a “boogie board,” says Donovan.

“When we know we have a cardiac arrest, we just place it onto a backboard and place our patient on the AutoPulse and backboard at the same time,” he explains.

Training was minimal, says Donovan, consisting of a 45-minute in-service with a videotape and some hands-on practice. The most difficult part, he says, was changing the compression strip that goes across a patient’s chest, which took about 10 minutes in the ED after handing over the patient.

Collier County has been so impressed with the device, they plan on equipping every rig in their system with an AutoPulse.

“I look forward to that,” says Donovan. “It’s better than riding in a rig and trying to do compressions. You just can’t get the same effective quality.”

ECCU: Emergency Cardiovascular Care Update

The 13th Biennial Emergency Cardiovascular Care Update conference, which meets September 30–October 3 in New Orleans, LA, focuses on new scientific research on emergency cardiovascular care worldwide. It is organized by the Citizen CPR Foundation and supported by the Heart & Stroke Foundation of Canada, American Heart Assn. and American Red Cross. Other partners are the European Resuscitation Council, South Africa, Australia, New Zealand and South America.

According to 2004 ECCU chair and Canadian paramedic Marc Gay, some of the top scientific issues slated for discussion will include: CPR teaching and learning, home defibrillation programs, therapeutic hypothermia and more. Attendees will have an opportunity not only to hear about controversial science issues, but to provide their own input to science reviewers about what they think is important and should be reviewed in light of what they teach or experience in their daily work.

“In 2000, we had the first International Consensus on Science,” says Gay. “There’s a whole scientific process for evaluating a number of topics, such as specific drug use, where international members, or the International Liaison Committee on Resuscitation (ILCOR), reach a consensus that is published as the International Consensus on Science and Treatment Recommendations. From the core scientific document, countries develop their own guidelines.”

Dozens of concurrent sessions and poster sessions are available to attendees, as well as a number of preconference sessions that will include: tools for measuring performance and outcome of CPR, presented by the National Registry for CPR; PALS, taught by top AHA instructors; how to establish a successful AED program; and how to incorporate videos, interactive computers, audiotapes, games, case-based learning and clinical findings when you teach.

“A timeline has now been determined for release of the next International Consensus on Science in 2005, which will coincide with our 2006 conference,” says Gay. “This is really a great conference for all prehospital providers.”

For more information on ECCU 2004 and future conferences, visit the Citizen CPR Foundation website at www.citizencpr.org.

A Sound Approach to Cardiac Care

Collier County (FL) EMS paramedics are currently testing new heart technology that helps emergency workers detect previously undetectable cardiac diseases before a patient arrives at a hospital.

The Audicor System, developed by Inovise Medical Inc., not only “listens” to the sounds of a patient’s heart, but also uses ECG analysis to monitor and provide computerized interpretation of electrical activity of the heart. The Audicor COR test produces a three-dimensional diagram, pinpointing potential trouble areas of the heart. By identifying abnormal heart sounds, it allows paramedics to identify problems at the earliest point of care and improve the patient’s chance of survival.

“This is a phenomenal technology,” says Jorge Aguilera, Collier County’s division chief of training. “We have been able to identify patients who were in the process of significant cardiac disease that would not have been detected with a traditional 12-lead but was detected with this technology. By early identification, we are able to take a patient who might have been triaged for ED evaluation and elevate his triage level to that of a cardiac patient, who receives more immediate attention in the ED.”

The V3 and V4 leads are actually microphones in the shape of electrodes that listen to heart sounds, Aguilera explains.

“An S3 heart sound follows the T-wave or repolarization period. An S4 sound would appear before ventricular contraction. Using the ECG rhythm, the computer program is able to predict when that sound would appear and knows where to listen for it. Traditionally, heart sounds have been good indicators, but listening to them has become a lost art because of the difficulty.”

Early detection of abnormal heart sounds allows medics to make different treatment choices, such as being more aggressive with nitrates or nitroglycerin, or giving blood thinners that were previously reserved for administration after finding more conclusive evidence at the hospital, rather than in the field or the back of an ambulance, says Aguilera.

“Historically, when it comes to MIs, paramedics have been limited to dealing only with patients with ST elevations—the evident ones where you can see on an ECG that they’re having an infarct,” he adds. “Audicor opens the door for non-ST-elevation MIs and being able to more aggressively recognize and treat them. From a paramedic standpoint, we’re not schooled to listen to heart sounds, and the environment we’re in is not conducive to doing so. This technology really takes away the guessing game.”

Aguilera cites an example of a patient who had no ST elevation on the 12-lead, no T-wave inversions, and an unremarkable ECG as interpreted by both an ED physician and a cardiologist. The patient was over age 40 with no history of congestive heart failure and met none of the cardiac criteria.

“Audicor picked up that this person had an S3 heart sound, which, at his age, made an S3 a pathological signal,” says Aguilera. “His ECG stayed normal, but, 48 hours later, there was a significant change in his troponin levels and he ended up having 85% occlusion of his left descending artery.”

For more information on the Audicor System, visit www.inovise.com/audicor/audicor.htm.

Defibrillation and Survival After Out-of-Hospital Cardiac Arrest

Recent studies published in the New England Journal of Medicine show that training and equipping laypersons to use AEDs on cardiac arrest victims in public locations increases rate of survival to hospital discharge.

Researchers conducted a prospective, community-based, multicenter clinical trial in which they randomly assigned community units, such as shopping malls and apartment complexes, to a structured and monitored emergency response system involving lay volunteers trained in CPR alone or in CPR and AED use. More than 19,000 volunteer responders from 993 community units participated in the trial. Patients were similar in age, proportion of men, rate of cardiac arrest in a public location and rate of witnessed arrest. No inappropriate shocks were delivered. There were more survivors to hospital discharge in units assigned to have volunteers trained in CPR and AED use (30 survivors of 128 arrests) than in units assigned to have volunteers trained only in CPR (15 survivors among 107 arrests). From this, researchers concluded that trained laypersons can safely and effectively use AEDs on victims of cardiac arrest.

A related article reported that bystanders performing CPR and using an AED save as many cardiac arrest victims as highly trained EMS providers. The chances of surviving a cardiac arrest nearly quadruple if fast-acting laypeople perform CPR instead of waiting for EMS, says the article, and more than triple if a shock from a defibrillator is delivered within eight minutes. Experts concluded that these findings could lead to significant changes in the way EMS systems across the country allocate resources.

EMS Magazine will follow up with a more extensive report on these studies in the November issue. The original articles can be found in the New England Journal of Medicine, Volume 351, #7, August 12, 2004.