Interactive Video: Using An AED For Sudden Cardiac Arrest (SCA)

V-Fib Lead II – Credit Glenlarson Wikipedia Commons

 

 

# 6823

 

Thirty-ahem years ago, I was lucky enough to have one of the first truly portable EKG/Defibrillators in my EMS rig. It was a Life-Pak 5, a museum piece now, but state of the art in 1976. 

 

While having it did increase our ability to revive ardiac arrest patients, the sad truth was that it could take 10 minutes for us to arrive on scene.

 

Often too long to be of much use to the patient unless effective CPR was started before our arrival.

 

Today, there are thousands of AED’s (automated external defibrillators) stationed in public areas like shopping malls, airports, bus terminals, schools, and other venues. Their early use during a cardiac arrest could easily make the difference between a patient’s survival or death.

 

AEDs are designed to be used by laypersons who ideally should have received some AED training.  Like doing CPR, the required skills are relatively simple, but they do require some degree of familiarity.

 

A buddy of mine (thanks, Cliff) passed along a link to an online training site that, in a few short minutes, can familiarize the layperson with what to do when confronted by a sudden cardiac arrest, and what to expect when opening and using an AED.

 

This interactive video is particularly well done, and is provided by the Medtronic Foundation, in conjunction with the Heart Rescue Project.  First the three steps you should know, then the video.

 

What to do if you see someone suddenly collapse.

If you see someone collapse suddenly, check if the victim is responsive. If not, remember these three easy steps.

Call 911

Have them send help. Stay on the line and listen for further instructions.

Start Chest Compressions

If the person is not breathing normally, start chest compressions. Push down hard and fast in the center of the chest. Keep your arms straight. Send someone to find an AED.

Use An AED

The AED (automated external defibrillator) is a portable medical device that delivers an electrical shock to restart a person’s heart. It provides voice prompts that tell you exactly what to do and will only administer a shock if needed, so there’s no reason to hesitate.

 

It only takes a few minutes to familiarize yourself with the operations of an AED by visiting the following website.   And if you haven’t taken a CPR class recently, make it a priority to get recertified.

 

LINK

 

I should point out that not all cardiac arrests can be corrected by defibrillation, even if conducted in a timely manner. There are non-shockable arrhythmias that an AED cannot convert to sinus rhythm.

 

Non-shockable cardiac arrest arrhythmias are asystole (flat line) and PEA (Pulseless Electrical Activity) – what we used to call back in the stone age of EMS, electromechanical dissociation.

 

Neither of which respond to defibrillation.

 

Patients can sometimes still be saved with CPR alone, at least until the right cardiac meds can be administered. For more on all of this, we have the press release from the American Heart Association.

 

Guidelines-based CPR saves more non-shockable cardiac arrest victims

April 02, 2012

Study Highlights:

• CPR can save someone with cardiac arrest even if they don’t respond to a defibrillator.
• People with non-shockable cardiac arrest are more likely to live if they receive CPR based on recent guidelines emphasizing chest compressions.
• The American Heart Association’s CPR guidelines emphasizing chest compressions are saving more lives, according to a new study.

 

 

Of course, despite your best efforts, many SCA victims will not survive. But early and coordinated action taken by bystanders (calling 911, starting CPR, using AED if available) can substantially improve their chances.

 

For more on heart attacks, and CPR, you may wish to visit some of these earlier blogs.

 

Deadlier Than For The Male

Survivability Of Non-Shockable Rhythms With New CPR Guidelines

Fear Of Trying

NPM11: Early CPR Saves Lives

»» Read More

Deadlier Than For The Male

Photo Credit – American Heart Association

 

 

# 6650

 

Although this blog deals primarily with emerging infectious diseases, this week is the 40th anniversary (Oct 1972) of my first job in EMS, and that ties nicely to an oral abstract presented at the 2012 Acute Cardiac Care Congress, which is being held this weekend in Istanbul, Turkey.

 

The subject is the impact of coronary heart disease on women, and differences in their symptoms and the treatment they receive. Their conclusion: Contrary to long held beliefs, heart attacks for women are deadlier than for the male.

At least in the cohort they studied. The abstract can be found at the link below: 

 

 

Are there gender differences in the management of ST-elevation myocardial infarction? Data from ORBI, a prospective registry of 5000 patients.

Guillaume LEURENT (Rennes, FR)

 

 

Note:  STEMIs are serious heart attacks that affect a large portion of cardiac muscle and show up on EKGs (ST segment elevation) and produce a spike in cardiac enzymes (indicative of muscle damage).

STEMI on EKG- credit Wikidoc.org

 

 

Fleshing out this abstract is a press release on the European Society of Cardiology’s website, from which I’ve excerpted portions below (bolding & Italics mine):

 

Women more likely to die from myocardial infarction than men

Gender gap in mortality is independent of patient characteristics, revascularisation delays and revascularisation modalities

 

Topics: Acute Coronary Syndromes (ACS)

Date: 20 Oct 2012

Doctors need to be more careful in the management of STEMI in women to further reduce ischemic time. This means adopting more aggressive reperfusion strategies and treating women the same as men. These actions by patients and doctors will reduce the current gender gap in mortality

Istanbul, Turkey – 20 October 2012: Women are more likely to die from a myocardial infarction than men, according to research presented at the Acute Cardiac Care Congress 2012.

 

The gender gap in mortality was independent of patient characteristics, revascularisation delays and revascularisation modalities. Women also had longer treatment delays, less aggressive treatment, more complications and longer hospital stays. The study was presented by Dr Guillaume Leurent from the Centre Hospitalier Universitaire in Rennes, France.

 

<SNIP>

 

“Previous studies on ST elevation myocardial infarction (STEMI) have shown that women have a worse prognosis, possibly due to longer management delays and less aggressive reperfusion strategies,” said Dr Leurent. “Therefore we used data from ORBI, a prospective registry of 5,000 STEMI patients, to find out whether there were any gender differences in the management of STEMI.”

 

<SNIP>

 

The researchers found significant differences in the management and outcome of STEMI patients according to gender.

 

Women had longer median delays between symptom onset and call for medical assistance (60 vs 44 minutes, p<0.0001) and between admission and reperfusion (45 vs 40 minutes, p=0.011).

 

“Delays of management are significantly longer in women, hence they have a longer ischemic time during which the heart’s blood supply is reduced,” said Dr Leurent. “And reperfusion strategies to restore blood flow are significantly less aggressive – with less fibrinolysis, and fewer coronary angiographies performed.”

 

Intra-hospital mortality was higher in women (9.0% vs 4.0%, p<0.0001). The researchers used 3 adjustment models to determine whether the higher intra-hospital mortality among women was solely due to gender or whether it was due to other factors such as patient characteristics (age, hypertension, smoking, etc) or management.

Dr Leurent said:

<SNIP>

 

Women had more STEMI complications including atrial fibrillation (7% vs 3%, p<0.0001) and longer hospital stays (7.6+4 vs 6.7+4 days, p<0.0001).

 

Women received significantly less of the recommended treatments at discharge. Specifically, they received less antiplatelet agents, beta blockers, ACE inhibitors and statins. They also received less cardiovascular rehabilitation (27% of women vs 47% of men, p<0.0001).

(Continue . . .)

 

 

At the risk of stating the obvious, this study was based on 5000 STEMI patients followed into 9 coronary care units in the Brittany region of France since 2006. Time to treat, aggressiveness in treatment, and outcomes may (or may not) be typical of those seen in other places around the globe.

 

The belief that heart attacks were predominately a `male problem’ was widespread four decades ago. Back then, if a man (over 40) had chest pain, your first thought would be `heart attack’. If a woman of the same age had chest pain, your first thought was more apt to be `gall bladder”.

 

Since then we’ve learned that women certainly have their share of heart attacks, but they don’t always show the same classic symptoms (e.g. crushing chest pain radiating down the left arm, dyspnea, diaphoresis) that men usually do.

 

Which probably explains number of middle-aged women we saw who died abruptly at home without ever calling for help. They apparently chalked up whatever warning signs they had to indigestion, or some other minor ailment.

 

The American Heart Association’s article Heart Attack Symptoms in Women explains the differences.

 

“Although men and women can experience chest pressure that feels like an elephant sitting across the chest, women can experience a heart attack without chest pressure, ” said Nieca Goldberg, M.D., medical director for the Joan H. Tisch Center for Women's Health at NYU’s Langone Medical Center and an American Heart Association volunteer. “Instead they may experience shortness of breath, pressure or pain in the lower chest or upper abdomen, dizziness, lightheadedness or fainting, upper back pressure or extreme fatigue.”

 

Even when the signs are subtle, the consequences can be deadly, especially if the victim doesn’t get help right away.

 

<SNIP>

 

Heart Attack Signs in Women

1. Uncomfortable pressure, squeezing, fullness or pain in the center of your chest. It lasts more than a few minutes, or goes away and comes back.
2. Pain or discomfort in one or both arms, the back, neck, jaw or stomach.
3. Shortness of breath with or without chest discomfort.
4. Other signs such as breaking out in a cold sweat, nausea or lightheadedness.
5. As with men, women’s most common heart attack symptom is chest pain or discomfort. But women are somewhat more likely than men to experience some of the other common symptoms, particularly shortness of breath, nausea/vomiting and back or jaw pain.

If you have any of these signs, don’t wait more than five minutes before calling for help. Call 9-1-1 and get to a hospital right away.

 

The following 3 minute film from Go Red for Women (starring Emmy-nominated actress Elizabeth Banks) illustrates the point nicely.

 

 

 

And finally, whether the victim is male or female - in the event of full cardiac arrest - having someone at hand with the skills to apply CPR can be lifesaving.

 

Luckily, today CPR is easier to do than ever.

 

Compression-only CPR is now the standard for laypeople, and so you don’t have to worry about doing mouth-to-mouth.

 

While it won’t take the place of an actual class, you can watch how it is done on in this brief instructional video from the American Heart Association.

 

A CPR class only takes a few hours, and it could end up helping you save the life of someone you love.

 

For more on the recent changes to bystander CPR, you may wish to visit these recent blogs.

 

CPR As A Requirement For High School Graduation

AHA Unveils 2010 CPR Guidelines

JAMA: Compression Only CPR

MMWR: Sudden Cardiac Arrest Awareness Month

»» Read More

Survivability Of Non-Shockable Rhythms With New CPR Guidelines

 

 

# 6262

 

 

We’ve a new study this week, appearing in the American Heart Association’s journal Circulation that looks at the survivability of OHCA  (Out of Hospital Cardiac Arrests) with non-shockable rhythms utilizing the new CPR guidelines that stress chest compressions.

 

Non-shockable cardiac arrest arrhythmias are asystole (flat line) and PEA (Pulseless Electrical Activity) – what we used to call back in the stone age of EMS, electromechanical dissociation. 

 

Neither of which respond to defibrillation.

 

Thirty-five years ago, most cardiac arrests started out with either pulseless ventricular tachycardia or (worse) ventricular fibrillation (both shockable rhythms) - that if not corrected - rapidly progressed to PEA or Asystole and ultimately death.

 

Which is why EMS put such emphasis on getting paramedics equipped with defibrillators and cardiac meds onto ambulances starting in the early 1970s.

 

But in recent years – for reasons that are not altogether understood – the number of shockable cardiac arrests is on the decline, while incidence of PEA and asystole are rising (see JEMS article  “Where Has V Fib Gone: Why today’s EMS crews see less ventricular fibrillation in the field.”)

 

Some researchers propose that better detection and earlier treatment of coronary artery disease may be responsible for this pendulum swing.

  

But with these gains come questions over whether the new standards for CPR – first unveiled in 2005 - work as well for non-shockable cardiac arrests.

 

Which brings us to the study, published earlier this week in the journal Circulation. You’ll find excerpts from the abstract below, but follow the link to read it (or the entire study) in its entirety.

 

Impact of Changes in Resuscitation Practice on Survival and Neurological Outcome after Out-of-Hospital Cardiac Arrest Resulting From Non-Shockable Arrhythmias

Peter J. Kudenchuk1; Jeffrey D. Redshaw; Benjamin A. Stubbs; Carol E. Fahrenbruch; Florence Dumas; Randi Phelps; Jennifer Blackwood; Thomas D. Rea; Mickey S. Eisenberg

 

Background—Out-of-hospital cardiac arrest (OHCA) claims millions of lives worldwide each year. OHCA survival from shockable arrhythmias (ventricular fibrillation/tachycardia) improved in several communities after implementing American Heart Association resuscitation guidelines that eliminated "stacked" shocks and emphasized chest compressions. "Non-shockable" rhythms are now the predominant presentation of OHCA, upon which the benefit of such treatments is uncertain.

<SNIP>

Conclusions—Outcomes from OHCA due to non-shockable rhythms, though poor by comparison with shockable rhythm presentations, improved significantly after implementing resuscitation guideline changes, suggesting their potential to benefit all presentations of OHCA.

 

For more on all of this, we have the press release from the American Heart Association.

 

Guidelines-based CPR saves more non-shockable cardiac arrest victims

April 02, 2012

Study Highlights:

• CPR can save someone with cardiac arrest even if they don’t respond to a defibrillator.
• People with non-shockable cardiac arrest are more likely to live if they receive CPR based on recent guidelines emphasizing chest compressions.
• The American Heart Association’s CPR guidelines emphasizing chest compressions are saving more lives, according to a new study.

 

DALLAS, April 2, 2012 — People who have a cardiac arrest that can’t be helped by a defibrillator shock are more likely to survive if given CPR based on updated guidelines that emphasize chest compressions, according to research reported in the American Heart Association journal, Circulation.

 

“By any measure — such as the return of pulse and circulation or improved brain recovery — we found that implementing the new guidelines in these patients resulted in better outcomes from cardiac arrest,” said Peter J. Kudenchuk, M.D., lead author of the study and professor of medicine at the University of Washington in Seattle, Wash.

 

The American Heart Association changed its CPR guidelines in 2005 to recommend more chest compressions with fewer interruptions. The emphasis on chest compressions continued in the 2010 guidelines update.

(Continue . . . )

 

 

All of which illustrates the importance of learning how to do effective CPR.

 

Luckily, today CPR is easier to do than ever.

 

Compression-only CPR is now the standard for laypeople, and so you don’t have to worry about doing mouth-to-mouth.

 

 

While it won’t take the place of an actual class, you can watch how it is done on in this brief instructional video from the American Heart Association.

 

A CPR class only takes a few hours, and it could end up helping you save the life of someone you love.

 

For more on the recent changes to bystander CPR, you may wish to visit these recent blogs.

 

CPR As A Requirement For High School Graduation

AHA Unveils 2010 CPR Guidelines

JAMA: Compression Only CPR

MMWR: Sudden Cardiac Arrest Awareness Month

»» Read More

MMWR: Out-of-Hospital Cardiac Arrest Surveillance

 

 

# 5728

 

Over the years I’ve written often about the importance of learning CPR, and on occasion, of my own experiences as a paramedic and as an American Red Cross and American Heart Association CPR instructor.

 

The first four or five minutes of any cardiac arrest are the most critical. And resuscitation efforts that are started after that time period are less likely to produce a good outcome.

 

Quite simply, since EMS response times are often longer than 5 minutes - when someone suffers cardiac arrest outside of the hospital – the patient’s ultimate survival hinges greatly on whether bystander CPR is started before help arrives.

 

Last week the CDC’s  MMWR released a surveillance summary that illustrates this point with data gleaned over the past 5 years from 911 Call Centers, EMS services, and Hospitals on OHCA’s (Out Of Hospital Cardiac Arrests).

 

Out-of-Hospital Cardiac Arrest Surveillance --- Cardiac Arrest Registry to Enhance Survival (CARES), United States, October 1, 2005--December 31, 2010

Surveillance Summaries

July 29, 2011 / 60(SS08);1-19

Bryan McNally, MD, Rachel Robb, MMSc,Monica Mehta, MPH,Kimberly Vellano, MPH,Amy L. Valderrama, PhD, Paula W. Yoon, ScD, Comilla Sasson, MD, Allison Crouch, MPH, Amanda Bray Perez, BS, Robert Merritt, MA, Arthur Kellermann, MD

Abstract

Problem/Condition: Each year, approximately 300,000 persons in the United States experience an out-of-hospital cardiac arrest (OHCA); approximately 92% of persons who experience an OHCA event die. An OHCA is defined as cessation of cardiac mechanical activity that occurs outside of the hospital setting and is confirmed by the absence of signs of circulation. Whereas an OHCA can occur from noncardiac causes (i.e., trauma, drowning, overdose, asphyxia, electrocution, primary respiratory arrests, and other noncardiac etiologies), the majority (70%--85%) of such events have a cardiac cause.

 

The majority of persons who experience an OHCA event, irrespective of etiology, do not receive bystander-assisted cardiopulmonary resuscitation (CPR) or other timely interventions that are known to improve the likelihood of survival to hospital discharge (e.g., defibrillation). Because nearly half of cardiac arrest events are witnessed, efforts to increase survival rates should focus on timely and effective delivery of interventions by bystanders and emergency medical services (EMS) personnel. This is the first report to provide summary data from an OHCA surveillance registry in the United States.

(Continue . . . .)

 

The entire report is detail rich and worth reading, but briefly:

 

In 2004 the CDC, in collaboration with the Emergency Department at the Emory University School of Medicine, began a pilot program called the Cardiac Arrest Registry to Enhance Survival (CARES).

 

This registry – which has since expanded to include 46 EMS agencies in 36 communities in 20 states – evaluates patients who received resuscitative efforts, including CPR or defibrillation, outside of the hospital following a coronary related cardiac arrest.

 

In evaluating 31,689 OCHA events, the registry found that the mean patient age was 64, 61.1% were male, and nearly half (47.3%) were witnessed by a bystander or EMS personnel.  Two thirds occurred at a home or residence, 13.5% in a nursing home or assisted living facility, and roughly 20% in public locations.

 

Just over 20% were pronounced dead at the scene by EMS personnel, while 26.3% survived to be admitted to the hospital.

 

Overall, the survival rate to hospital discharge was 9.6%.

 

Although 36.7% of these cardiac arrests were witnessed by bystanders, less than half (43.8%) of those received bystander CPR, and only 3.7% of those were treated with an AED prior to the arrival of EMS.

 

Among those who received bystander CPR or AED treatment, the survival rate to hospital discharge was 11.2% as opposed to just 7% for those who received no CPR.  

 

A 60% improvement in the survival rate.

 

 

In conclusion, the authors write:

 

The data provided in this report indicate the need for prompt and effective resuscitation efforts. Provision of optimal care at the scene is essential to survival. If a pulse is not restored before EMS transport, additional efforts at the receiving hospital almost invariably fail (23).

 

Education of public officials and community members about the importance of increasing rates of bystander CPR far beyond the current 33.3% and promoting use of early defibrillation by lay and professional rescuers are critical to improving survival of OHCA events. CARES data can be used at the community level to target interventions (e.g., bystander CPR training and AED placement) and assess their effectiveness. CDC uses CARES data for cardiovascular surveillance efforts and makes data available to the public at http://apps.nccd.cdc.gov/NCVDSS_DTM. As statewide CARES registries become available, the data will be used for state-specific OHCA surveillance efforts.

 

With expansion to state-level surveillance, CARES will enable local and state public health departments and EMS agencies to better coordinate their efforts. Such coordination can improve the quality of EMS care and thus increase the proportion of persons who survive an OHCA event.

 

Luckily, today CPR is easier to do than ever.

 

Compression-only CPR is now the standard for laypeople, and so you don’t have to worry about doing mouth-to-mouth.

 

This from the American Heart Association.

• Sudden cardiac arrest is a leading cause of death in the U.S.
• Everyone should know how to perform CPR in an emergency.
• Immediate, effective CPR could more than double a victim's chance of survival.
• Push on the chest at a rate of at least 100 beats per minute.
• Push to the beat of "Stayin' Alive" and you could save a life.
• Click here for more information on Hands-Only CPR.

 

While it won’t take the place of an actual class, you can watch how it is done on in this brief instructional video from the American Heart Association.

 

A CPR class only takes a few hours, and it could end up helping you save the life of someone you love.

 

To find a local CPR course contact your local chapter of the American Red Cross, the American Heart Association, or (usually) your local fire department or EMS can steer you to a class.

 

For more on the recent changes to bystander CPR, you may wish to visit these recent blogs.

 

CPR As A Requirement For High School Graduation

AHA Unveils 2010 CPR Guidelines

JAMA: Compression Only CPR

MMWR: Sudden Cardiac Arrest Awareness Month

»» Read More

Study: Predictors Of Sudden Coronary Death

 

 

# 5714

 

 

According to The American Heart Association (data for 2009) every year an estimated 785,000 Americans experience their first heart attack, and another 470,000 suffer a recurrent heart attack. They also estimate another 195,000 `silent’ myocardial infarctions occur each year.

Making for just under 1.5 million coronary attacks a year (cite Lloyd-Jones D, Adams RJ, Brown TM, et al. Heart Disease and Stroke Statistics—2010 Update. Circulation. 2010;121:e1-e170).

 

While many people survive their first heart attack, for far too many Americans, their first heart attack is also their last. 

 

Every year American EMS units respond to roughly 300,000 cardiac arrests, and the vast majority of those prove fatal (cite  AHA CPR Stats). Why some people survive their first heart attack, and others do not, has been a subject of considerable interest for many years. 

 

The BMJ journal HEART recently published an article that looks at ECG and clinical predictors of sudden cardiac death. 

 

Electrocardiographic and clinical predictors separating atherosclerotic sudden cardiac death from incident coronary heart disease

Elsayed Z Soliman, Ronald J Prineas, L Douglas Case, Gregory Russell, Wayne Rosamond, Thomas Rea, Nona Sotoodehnia, Wendy S Post, David Siscovick, Bruce M Psaty, Gregory L Burke

 

 

While this study found many commonalities between those who suffer sudden cardiac death and those who survive their heart attacks, researchers found several risk factors that appear to suggest a higher risk of sudden death.

 

• Black race/ethnicity (compared to non-black)
• Hypertension and increased heart rates
• Extreme high or low body mass index

Additionally, ECG readings showing a prolongation of QT interval (QTc) and abnormally inverted T waves were seen as possibly being predictors of a higher risk of sudden cardiac death.

 

This research was conducted at the Epidemiological Cardiology Research Center (EPICARE) at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina.

 

The authors conclude by stating that these results need to be validated in another cohort.

 

A press release, with more details, is available on the Wake Forest Medical Center Website.

 

 

Predictors of Dying Suddenly Versus Surviving Heart Attack Identified

WINSTON-SALEM, N.C. – July 25, 2011 – Is it possible to predict whether someone is likely to survive or die suddenly from a heart attack?

 

A new study by researchers at Wake Forest Baptist Medical Center has answered just that.

 

“For some people, the first heart attack is more likely to be their last,” said Elsayed Z. Soliman, M.D., M.Sc., M.S., director of the Epidemiological Cardiology Research Center (EPICARE) at Wake Forest Baptist and lead author of the study. “For these people especially, it is important that we find ways to prevent that first heart attack from ever happening because their chances of living through it are not as good.”

(Continue . . . )

 

 

While preventing that first heart attack is a laudable goal, this is an excellent time to remind my readers of the importance of learning CPR. 

 

This from the American Heart Association.

 

• Sudden cardiac arrest is a leading cause of death in the U.S.
• Everyone should know how to perform CPR in an emergency.
• Immediate, effective CPR could more than double a victim's chance of survival.
• Push on the chest at a rate of at least 100 beats per minute.
• Push to the beat of "Stayin' Alive" and you could save a life.
• Click here for more information on Hands-Only CPR.

Today, CPR is easier to do than ever.

 

Compression-only CPR is now the standard for laypeople, and so you don’t have to worry about doing mouth-to-mouth.

 

While it won’t take the place of an actual class, you can watch how it is done on in this brief instructional video from the American Heart Association.

 

A class only takes a few hours, and it could end up helping you save the life of someone you love.

 

To find a local CPR course contact your local chapter of the American Red Cross, the American Heart Association, or (usually) your local fire department or EMS can steer you to a class.

 

For more on the recent changes to bystander CPR, you may wish to visit these recent blogs.

 

CPR As A Requirement For High School Graduation

AHA Unveils 2010 CPR Guidelines

JAMA: Compression Only CPR

MMWR: Sudden Cardiac Arrest Awareness Month

»» Read More

Home Is Where The (fatal) Heart Attack Is

 

 

# 5262

 

Yep, that’s me - circa 1976 with my (now museum piece) LifePak 5 (and an almost full head of hair).

 

While I try not to tell paramedic `war stories’, or go out of my way to make this blog about me, every once in awhile I can’t resist throwing in a personal anecdote.

 

In August of 1974 I was among the first 36 D.O.T. paramedic graduates in the state of Florida. With portable defibrillators, IVs, Cardiac meds, and radio telemetry on board - everyone expected us to start saving lives left and right.

 

And while our `saves’ went up, they didn’t go up as dramatically as many hoped.

 

Sure, we had some great saves - particularly among younger patients, drowning victims, and trauma.   

 

But overall, our cardiac arrest success rate was dismal.   Perhaps now, after all these years, we may have a better clue why.

 

First, a quickie lesson in heart attacks and EKGs (the readout of the electrical activity of the heart). 

 

In a cardiac arrest, the patient is pulseless, usually non-breathing, and unable to circulate oxygenated blood to the brain and other organs. Death follows generally in 4 to 10 minutes.

 

But not all pulseless arrests are created equal.

This is bad.

(Ventricular Tachycardia)

 

This is very bad

(Ventricular Fibrillation)

 

And this is worst of all.

(Asystole)

 

 

The first two rhythms strips are considered `shockable’ arrhythmias. The heart may not be beating, but there is still some (albeit, chaotic) electrical activity going on. 

 

Applying an electrical shock promptly enough can often restore NSR (normal sinus rhythm) to a stopped heart. 

 

But despite what you may have seen in the movies, and on television, you can shock an asystolic (flatlined) heart all day long without much hope of success.   

 

There are some cardiac meds that can (rarely) convert asystole to fibrillation, but defibrillation alone is generally futile.

 

 

Yesterday the NIH announced  a study comparing the type of cardiac arrests experienced by people at home verses people who collapsed in public.

 

And the results are fascinating.   At least to an old EMT-II like myself.

 

First, some excerpts from the press release, then a link to the NEJM study, after which I’ll be back with a little more.

 

 

Shockable cardiac arrests are more common in public than home

Comprehensive NIH study helps explain discrepancy in survival rates between cardiac arrests in public and at home

Cardiac arrests that can be treated by electric stimulation, also known as shockable arrests, were found at a higher frequency in public settings than in the home, according to a National Institutes of Health-funded study appearing in the Jan. 27 issue of the New England Journal of Medicine.

 

The study compared home and public cardiac arrests under various scenarios. For example, the study considered whether bystanders or emergency medical services (EMS) personnel witnessed the cardiac arrest, and whether the person experiencing the arrest received treatment with an automatic external defibrillator (AED).

 

In every scenario, a higher percentage of public cardiac arrests were classified as ventricular tachycardia (VT) or ventricular fibrillation (VF), the types of abnormal heart rhythms that can be treated by electric shock.

 

More than one-third of the people who had a cardiac arrest in public and were treated with an AED survived. This is a significant improvement over the roughly 8 percent national average of cardiac arrest survival. In comparison, the overall survival for home-occurring cardiac arrests treated with an AED was 12 percent.

(Continue . . .)

 

Ventricular Tachyarrhythmias after Cardiac Arrest in Public versus at Home

 

Myron L. Weisfeldt, M.D., Siobhan Everson-Stewart, Ph.D., Colleen Sitlani, M.S., Thomas Rea, M.D., Tom P. Aufderheide, M.D., Dianne L. Atkins, M.D., Blair Bigham, M.Sc., Steven C. Brooks, M.D., M.H.Sc., Christopher Foerster, M.Sc., Randal Gray, M.A.Ed., Joseph P. Ornato, M.D., Judy Powell, B.S.N., Peter J. Kudenchuk, M.D., and Laurie J. Morrison, M.D. for the Resuscitation Outcomes Consortium (ROC) Investigators

N Engl J Med 2011; 364:313-321January 27, 2011

(Read Full Report . . . )

 

 

Like all studies, there are limitations to this one.

 

Some assumptions regarding the arrhythmias of successfully cardioverted arrest victims using AEDs (which only shock when they detect VT or VF) had to be made in lieu of actual EKG strips.

 

Likewise, home heart attacks (where AEDs are less likely to be found, or the patient’s collapse witnessed) may have started with VT or VF and progressed to asystole by the time rescuers with their EKGs arrived.

 

But even when you take these items into account, it appears that cardiac arrests that occur in public are far more likely to be a `shockable’ (VT or VF) rhythm than those that occur in the home.

 

This likely has more to do with the age, and physical condition of the patient, than the actual location.  Those who are able to be out and about are probably in somewhat better overall health than those who are house bound.

 

All of which points out the benefits of putting more AEDs in public places, and promoting lay person CPR and AED training. 

 

The authors of this NEJM report conclude:

 

Conclusions

Regardless of whether out-of-hospital cardiac arrests are witnessed by EMS personnel or bystanders and whether AEDs are applied by bystanders, the proportion of arrests with initial ventricular fibrillation or pulseless ventricular tachycardia is much greater in public settings than at home. The incremental value of resuscitation strategies, such as the ready availability of an AED, may be related to the place where the arrest occurs. (Funded by the National Heart, Lung, and Blood Institute and others.)

 

 

For more on the recent changes to bystander CPR, you may wish to visit these recent blogs.

 

CPR As A Requirement For High School Graduation

AHA Unveils 2010 CPR Guidelines

JAMA: Compression Only CPR

MMWR: Sudden Cardiac Arrest Awareness Month

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