The Evolving Science and Guidelines of CPR

Pearl of wisdom for the day: If given the option, don’t let your heart stop.  Very Bad Things soon follow if your heart stops.

In spite of what the entertainment industry would have you believe, it is extremely difficult to save the life of someone in cardiac arrest.  A few random breaths, slow rocking chest compressions, even the ever-so-dramatic overhand blow to the chest accompanied by the scream “Don’t you die on me, dammit!” are unlikely to successfully resuscitate someone following an arrest, and even if it does, they won’t be in any shape to go chase Locke across the island with Jack and Kate five minutes later.

Even with properly performed CPR, started within seconds of an arrest, in a hospital with all the required expertise and support equipment, only roughly half survive their initial arrest event.  Even fewer (25-33%) survive to discharge from the hospital, and ~75% have a good neurologic outcome.  For arrests out of the hospital, where there can be huge delays in treatment, mere survival is significantly lower, often measured in the single digits.

The Limitations Of CPR

Why doesn’t CPR save more people?  Well, it really isn’t meant to; at least, not on its own.  Cardio-respiratory arrest is the common pathway of death, but it isn’t in itself a diagnosis.  The essential question to be answered is why someone stopped breathing, or why their heart stopped in the first place.  Unless you can answer that question and address the problem, even if CPR manages to restore a heartbeat it’s likely to stop again in short order.

It’s clearly unrealistic though to expect a random bystander to diagnose and treat another random stranger who happened to arrest in their vicinity.  The rescue breaths and chest compressions of CPR are therefore primarily designed to buy time, hopefully enough time to get to the EMTs and Emergency/Critical Care team whose job it is to figure out what caused the arrest in the first place and reverse it before permanent damage is done.

In spite of the availability of public CPR training courses and the widespread knowledge of the existence of CPR, most people remain untrained, and the vast majority of those who have been trained (even medical personnel) rarely have cause to think about the skill, much less practice it.  The result is that complete novices in CPR are the first responders to the overwhelming majority of arrests.  Should we be surprised, then, that in no more than half of all arrests is any CPR provided by bystanders, and that the quality of CPR when it is given is often sub-par?

I don’t mean that as an indictment of innocent bystanders of an arrest.  Simply witnessing an arrest is traumatic enough; to be in such a situation and asked to recognize the emergency, remember distant and somewhat arcane training, to have the initiative and courage to step forward and act, and to do so quickly and effectively is an immense amount to expect from anyone.  Nevertheless, if the goal is to reduce the amount of time a victim of an arrest is without circulation, we needed to find some way to enable more people to provide quality CPR.


The desire to reduce these impediments to good CPR delivery, combined with improved understanding of the physiology of people during arrests and CPR, led the American Heart Association (AHA) to make some significant revisions to its CPR guidelines in 2005.  The revised guidelines were notably more streamlined, focusing less on tools, drugs, and advanced skills used by professionals, and even reducing the emphasis of breathing to focus instead on simply maintaining circulation of blood.  Instead of a variety of age stratified ratios of compressions to rescue breaths, the AHA began to teach a single universal guideline for single bystander CPR: 30 compressions at a rate of 100/minute, then 2 breaths, then repeat until either help arrives or the person is breathing on their own.  Compared to the prior CPR guidelines, it was simpler, easier to remember, and easier to execute.

In 2008 this was simplified even further.  For adult cardiac arrests, it was demonstrated that “compression-only” or “hands-only” CPR was equally effective to CPR using both compressions and rescue breathing, yet was simpler, even easier to remember, had fewer interruptions, and eliminated the aversion to mouth-to-mouth that some people experience.  All of this is thought to make people more likely to intervene and provide quality CPR, improving the odds of a dire situation.

Though it may seem counterintuitive not to provide rescue breaths for someone in cardio-respiratory arrest, the rationale is solid.  “Deoxygenated” or venous blood still has a good amount of oxygen in it (usually about 75% of oxygenated blood), and it carries a lot more than just oxygen.  The blood content of the nutrients that cells require is largely the same no matter whether the blood has been oxygenated or not, and blood flow also removes harmful metabolic byproducts that build up rapidly in its absence.  Though breathing is necessary in the long run, but you can get by without breathing a lot longer than you can survive without blood flow.

Studies have confirmed that “compression-only” and conventional CPR are equally efficacious in adult cardiac arrests, and that the “compression-only” method is easier to learn and remember.  By reducing the complexity of CPR to something that essentially fits on a bumper sticker, we are likely to improve the overall odds for adults who arrest out of the hospital.

…But Maybe Not That Simple

Have we made it too simple though?  Children arrest too, but for very different reasons than adults.  Most kids suffer respiratory arrests that then cause cardiac arrest, not primary cardiac arrests like most adults.  Eliminating rescue breathing from childhood resuscitations could in fact result in worse outcomes.  The AHA and medical community at large are aware of this, which is why the “compressions-only” CPR has not been recommended for children.  Even so, it is likely that in advocating for “compression-only” CPR to benefit adults, some children will inadvertently be subjected to sub-optimal CPR.

A new study out of Japan and published last month in The Lancet provides some sobering but powerful information that may guide future CPR guidelines.  The investigators examined all arrests of children over a 3-year span in Japan, documenting the type of arrest, presence and type of CPR, and short and long-term outcomes among other measures.

Out of 5158 childhood arrests, 2719 (53%) had no CPR attempted by anyone prior to EMS arrival.  Survival rates were abysmally poor without CPR at ~7% alive one month after arrest.  Though still depressingly low, CPR significantly improved survival to ~11%.  Of equal importance, those above 1 year of age who did get CPR, any type of CPR, also had markedly better odds of having favorable neurologic function at one month from the arrest.  As with the adult experience, an arrest out of the hospital is a dire situation, but any type of CPR is better than nothing, and can have a marked improvement in the (unfortunately small) likelihood of having a positive outcome.

The concern I had, however, was whether inappropriate “compression-only” CPR was inferior to conventional CPR with both compressions and rescue breaths, and whether we need to keep this in mind when designing our CPR program for the public.  The authors of this study were able to make just such a comparison.  Both forms of CPR were equally effective when the arrest had a cardiac origin, just as we’ve seen in adults.  However, as suspected, victims of arrests of a non-cardiac origin provided “compressions-only” CPR did no better than those given no CPR; only the combination of compressions and rescue breathing affected a significant benefit.

Furthermore, of the 2,439 children who did receive CPR, 36% received “compression-only” CPR.  Since 71% of all of the arrests in this study were non-cardiac in origin, this means that 25% of the CPR administered was inappropriate and ineffective.

Clearly, this study has limitations in being observational in design, and there are obvious issues generalizing from the Japanese population to that of the US, among other smaller concerns.  Nevertheless, this study provides a few important lessons to be considered.

First, it shines the harsh light of reality on the overly optimistic expectations of CPR sometimes provided but the news media and frequently by the entertainment industry.

Second, it demonstrates the efficacy of CPR in improving both survival and the quality of outcomes from out of hospital arrests, and the potential benefits of further enabling the public to perform appropriate CPR.

Third, it reinforces the decision of the AHA to restrict “compression-only” CPR to adults with suspected cardiac arrest, and not to apply it to children.

Finally, it seems to validate my concern that the introduction of “compression-only” CPR may be detrimental to the pediatric population.  Recall that the two CPR techniques were equally efficacious in adults (and apparently children) with an arrest of cardiac origin.  The AHA has therefore assumed that there was no detriment to the further simplification of the CPR guidelines, while yeilding a theoretical benefit derived from better quality of compressions and a greater percentage of bystanders willing and able to provide CPR.  If, however, “compression-only” CPR is only equal to conventional CPR in the adult population yet generates a negative impact on the quality of CPR provided to children, the AHA may choose to reconsider the wisdom of advocating “compression-only” CPR.  Obviously, this is still an open question, and further studies are needed (and are currently being performed), but I am curious how this information may affect the new guidelines due for release late 2010.

We will continue to refine the CPR guidelines to improve the outcomes from out of hospital arrests using the best available science, but the largest area for improvement is in the number of people in the community trained and willing to perform basic CPR.  It’s cheap, it’s easy, and the classes are actually fun.  Though you will hopefully never use the skill, you have the ability to help save a life.  Please, if you are at all inclined, get CPR certified.

Posted in: Science and Medicine

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36 thoughts on “The Evolving Science and Guidelines of CPR

  1. Thanks for a very informative post, Joseph. I was unaware that compression only CPR was only recommended for adults.

    I’m surprised that in your opening you didn’t mention that you can’t/don’t shock a flat-line, which is probably the biggest Hollywood myth/error regarding cardiac arrest.

  2. Anarres says:

    Very useful, thanks. Four years ago I suffered a MI later a FV while on catheterization -and some minor burns :) on my hairy chest from the defribillator- .

    I showed the CPR video to my family. The Spanish NHS is very good, I think that it’ s true that hospitals are modern and well-equipped but there isn´t CRUs in many of them. Furthermore I live in a little town. At that time the public hospital did have some troubles like lack of trained personnel.

    The first cardiologist I meet he didn´t emphatise with me. He arrived from Peru, I only say this because maybe his education -or life- was different. I still remember when he told me “I give you all the drugs you can bear” with no explication at all. A surly men. A year later I left them all except for aspirin.

    I was discharged after a week with poor education about CV diseases. I´m an ordinary person. On the following day I spend ten hours in the Hospitals hall, enduring a massive overcrownding in the Emergency Room. I spend that time because nobody warmed me about the effects of the betablockers, they lowered my heart rate to 40/min.

    My PCP was a negligent old men. Fortunately he is now retired. And he was badly wrong, he told me that my cholesterol levels were right so I could stop to worry about it. Then I abandoned the betablockers -I understand now the risks- and the statins on my own…

    But nowadays I read medicine books -and many others- and I understand very well why I need statins and other drugs. So today I comply with the prescription, I understand my first cardiologist stance and I have a young and concerned PCP and I trust her.

  3. edgar says:

    My Daughter was born at 35,5 weeks and had a 5 day NICU stay. About the most ridiculous thing that happened was the neonatal resuscitation video, and the instructions to practice on our arms on ‘courtesy night.’

    I even remember thinking it is stupid, and that no way a new mom with a preemie baby was EVER going to remember any of it.
    And it only served to freak me out even more.

  4. bluedevilRA says:

    As Karl points out, asystole is an unshockable rhythm. And I really do hate the cliche of “hey, let’s shock him and then *poof* he magically comes back to life!”

    However, I wonder if it really hurts to try. Is it possible that they have a weak (vfib or vtach) rhythm that is undetected by the ECG?

  5. Harriet Hall says:

    At least 90% of the depictions of CPR I have seen in movies and on TV wouldn’t work. Sometimes they leave the patient on a soft surface that “gives” with every compression, sometimes they let their arms bend so the motion is in their own arms and not applied to the chest, and even when they use the straight arm technique they don’t use enough force to move the chest wall enough to compress the heart. In the elderly, sometimes you have to break a rib to do effective CPR.

  6. Noe says:

    I totally agree that it would benefit us all if more of the public were well-versed in proper CPR. Maybe it could be taught in high schools.

    But you can hardly expect them to learn it from TV shows – it’s entertainment, not a training video. Don’t get me wrong – I do my fair share of yelling “But that would never happen!” at the screen.

  7. CodeSculptor says:

    With regards to the Hollywood CPR depictions, most of the time the reason is because they are working on each other (meaning one actor actually kneeling over the other actor with their hands on the chest) — so the compressions would be contraindicated (insurance, commotio cordis, bruising and broken ribs)…

    Do they still show precordial thumps on tv anymore?

  8. “Do they still show precordial thumps on tv anymore?”

    They’ve done them on House several times. At least as recently as Episode 15 (Season 4): House’s Head.

  9. Robin says:

    @ Noe, I was taught CPR in high school health class, as well as basic first aid. The fire department came in to give instruction, and brought practice dummies, and we all had to learn it. Students had the option of getting certified (on their own time) and some went on to become Fire and Ambulance Explorers. My friends did it, and I got to be a victim at a “mock rescue’!

    I read about the compression-only but I haven’t reviewed CPR in a while. It’s one of those things that would be good to do on a regular basis, like change the smoke alarm batteries during daylight savings. Maybe when my family is together this summer at our fourth of July, I’ll make everyone watch a video!

  10. Noadi says:

    It was part of my highschool health class as well that everyone learned CPR and got certified along with learning first aid. I’ve never had to use CPR on anyone though the first aid training has come in handy many times.

    This post reminds me that I should find a refresher class in CPR and first aid to take since it’s been almost 10 years since I took one.

  11. _Arthur says:

    I remember that scene in “Black Hawk Down”, the grieviously wounded soldier goes into heart failure while they were practicing field surgery upon him.

    They try CPR.

    I never understood why they thought that pumping the chest of a man bleeding profusely from many bullet wounds would somehow revive him.

    I suppose they had to try something.

  12. manixter says:

    Shocking the heart is not harm free. If it is a shockable rthym (sorry can’t spell) then the risk is balanced by the benefit of establishing a perfusing rythm (CPR supposedly 25% of cardiac output). Until one gets a perfusing rythm CPR will perfuse the brain (important for later) as well as the heart (hopefully oxygen to the heart will allow for recovery of function or at least a shockable rythm).
    A case from one of the earliest cases of CPR (1960ish) had 40 min of CPR before they could wheel the defibrillator down. The man survived intact.
    The first successful open and closed chest defib was in the or, by the way. The development of bystander CPR and the idea of rescue breaths was largely due to Peter safar of Pittsburgh (thank your anesthesiologist next time you see them). And the first cases of successful closed chest cardiac massage was on pediatric patients (1958).

  13. manixter says:

    Peter safar was an anesthesiologist in Pittsburgh whose daughter drowned. He passed on a few years ago but the safar center lives on.
    I drowned in 1975 and my mother used CPR she learned as a nurse to save me. I’m an anesthesiologist in Pittsburgh and I met Peter safar during my training.

  14. manixter says:

    Peter safar also introduced the quaint idea that ambulance personnel should be medically trained to provide rescusitation on the way to the hospital.

  15. cglenn says:

    In Canada compression-only CPR has not been recommended. As a first aid instructor I have concerns with having another branch in the decision tree. If conventional CPR is just as effective as compression-only CPR then why not just teach conventional CPR since compression-only CPR is less effective not only for children but also for drowning victims, some overdoses, and suffocation. Then the learners only have one skill to learn and fewer decisions to make. First aid classes are full of information, which can lead to cognitive overload, reducing the complexity of the learning will lead to greater retention of the skills.

    Right now it’s pretty clear.
    1. Casualty is unconscious = Call 911
    2. Open Airway
    3. Check Breathing
    a) If breathing roll into recovery position
    b) If not breathing start CPR
    4. Get an AED

  16. StatlerWaldorf says:

    I too didn’t know about the recommendation for compression only CPR (for adults at least).

    It has been 10 years since I last learned CPR, so I think I’ll retrain. Thanks for this very useful article!

  17. BillyJoe says:

    “nobody warmed me about the effects of the betablockers, they lowered my heart rate to 40/min.”

    My heart rate is already 40 bpm without betablockers. I hope nobody gives them to me by mistake. My heart might actually stop beating altogether!
    (Actually, I know there is a ventricular escape rhythm. When I was running marathons, my resting pulse rate would actually drop below the ventricular rate and the ventricular escape rhythm would take over… just as I was dropping off to sleep of course – very disconcerting)

    “I never understood why they thought that pumping the chest of a man bleeding profusely from many bullet wounds would somehow revive him.”

    Same at accidents where someone has died due to massive blood loss and they try to revive the vctim with CPR

  18. Tim Kreider says:

    Several news stories on hands-only CPR mentioned that a good way to keep the 100/min pace is to think of the beat of the song Stayin’ Alive (or, more darkly, Another One Bites the Dust).

    Tangentially, a surgeon on my campus gives every class an hour-long lecture on exsanguination in public, i.e. how not to let people bleed to death after accidents. His battle cry is that any artery, aside from the aorta itself, can be stopped with pressure applied by a single finger. He shows us story after horrible story, newspaper accounts of a child or young person bleeding to death in front of dumbfounded onlookers, any of whom count have provided a life-saving therapy. Common mistakes are putting an entire hand over the bleeding area instead of one finger, or applying pressure through layers of cloth instead of directly on the torn artery.

    Does the AHA or any other group make good PSAs about dealing with bleeding injuries? Maybe less common than cardiopulmonary arrest, but seems like an easier and more effective intervention.

  19. bluedevilRA says:

    manixter, I know shocking the heart is not risk-free. I was asking specifically in situations where the patient’s heart has literally stopped beating according to ECG. Thus, if pushing drugs does not work and the heart still fails to beat, then it would be appropriate to try one less shock?

    I do not think it could cause harm to a person that is for all intents and purposes dead. As I said, I am speculating on the possibility that they have a shockable rhythm that is undetectable by ECG. Does anyone know if this is possible?

    Tim, I think the issue with bleeding is that so many people are uncomfortable with blood, just as many people are uncomfortable with mouth-to-mouth. I think it would take an aggressive campaign with PSA’s and maybe school/workplace programs to convince people to do it. The sad thing is, anyone can be trained to do CPR in a few hours, but less than half of people take the time to learn. I think a lot of people adopt the philosophy of “it’s not my job. I will just call the paramedics because its their job.” The PSAs should therefore do a good job of convincing people of the need for early CPR and early defibrillation through easy-to-use AEDs.

  20. overshoot says:

    In the elderly, sometimes you have to break a rib to do effective CPR.

    In young adults, too. Unfortunately the patient was bleeding out faster than we could pour fluid in and had enough internal volume that although we got her heart restarted, she was pumping saline by the time she got to where there was blood available.

  21. JMB says:

    I worked with a decorated Vietnam war surgeon. He observed that external CPR in a patient with blood loss was usually ineffective because of the small size of the heart, so they would open the chest for direct cardiac massage, but the success rate was still dismal. Obviously you can’t open the chest without having a nearby OR. I might take away from that observation that if you try CPR on somebody with massive blood loss, then your goal for depth of compression must be increased (fracturing ribs or sternum would be more common, even in young people, as noted by overshoot).

    The inexperienced observer may have trouble distinguishing massive blood loss from minimal blood loss (a little bit might look like a lot). A small percentage of cardiac arrests even in patients with what looks like significant blood loss might be due to heart attacks or vagal reflexes before the blood volume has been depleted to the point of no return. So CPR is still attempted, and may be successful.

    In any event, CPR is attempted in spite of the low success rate.

  22. Astrid_H says:

    In Germany people are required to undergo CPR training when they get their driver’s licens. We learned the conventional CPR method, though frankly I’m not sure I’d have remembered what to do and in which order before this post. The compression only technique seems far simpler and more likly to be done by bystanders.

    I think both approches should be taught.

  23. borealys says:

    I’ll take cglenn’s word that compression-only CPR hasn’t been recommended in Canada … been a few years since my last recert, so I wouldn’t know anymore … but I do recall almost ten years ago being informed about it by a first aid instructor. Someone in the class asked what to do if the situation made it dangerous to do mouth-to-mouth (if the person had a bloody lip, say, or was known to have some nasty disease). The instructor said she was aware of some research suggesting that compression-only CPR was as good, or almost as good, as CPR with artificial respiration.

    Of course, this was the same instructor who didn’t bother teaching the class how to landmark for the Heimlich maneuver, so half of the students were doing abdominal thrusts way up against the lower ribcage. Most of the students who weren’t already trained to some degree walked out of that class saying they’d never feel confident to attempt CPR, despite their newly-earned certification. What a waste.

    As for TV, probably the most egregious depiction of CPR I ever saw was one that was supposedly a re-enactment of a real-life rescue. The rescuer, after trying a few rounds of more-or-less realistic CPR, and getting no response, screamed in frustration, straddled the guy’s hips, and started punching him in the chest with both hands. And then he woke up, and was okay!


  24. BillyJoe says:

    I’m sure my father didn’t know the Heimlich manouevre when he saved my life at the age of 13. As I was lapsing into unconciousness, he turned me upside down and thumped me hard in the middle of my back. Instant success, and I’m here to tell the tale. If it wasn’t for him the last thing I would have seen is a room full of terrified faces watching me die.

    When people ask me am I scared of death, I tell them I’ve been there and back and everything now is a bonus.

  25. manixter says:

    “I was asking specifically in situations where the patient’s heart has literally stopped beating according to ECG. Thus, if pushing drugs does not work and the heart still fails to beat, then it would be appropriate to try one less shock?”

    Electrical activity != heartbeat. The EKG does not detect heartbeats or any muscular activity in the heart– just electrical activity. It is possible to have electrical activity but no perceivable or effective muscular activity– that’s the definition of PEA (pulseless electrical activity). There has to be certain patterns of electrical activity to coordinate appropriate muscular activity (perfusing rhythm). Some patterns of electrical activity are not compatible with a perfusing rhythm but with the application of an external shock can be converted to electrical activity that is compatible with a perfusing rhythm– such as ventricular tachycardia and ventricular fibrillation. PEA (electrical rhythm OK but no pulse) can only be made worse with shock– treatment requires treatment of underlying causes (hypoxia, acidosis, exsanguination etc). Asystole does not respond to electric shock (it’s not like jump starting your car), so that a shock in this situation can only make things worse (damaging myocardium)– treatment again is related to correcting other conditions (hypoxia etc) so as to hopefully restore the ability of the heart to generate a perfusing rhythm or at least one that can be converted to a perfusing rhythm.
    It is exceedingly unlikely (never seen even a case study) that there would be a shockable rhythm not detected by the EKG. It is remotely possible that an automated external defibrillator (AED) could misdiagnose a rhythm– this would not be a reason for a layperson to shock “just in case”. In fact, the operator must direct the AED to shock with an appropriate rhythm, since an inappropriate shock could be harmful (so likely that many bystanders might not such with a shockable rhythm). It is much more likely for a bystander to cause harm by to defibrillating inappropriately by mistake or intent (which is why they can’t be overridden to shock) than to cause harm by delaying a defibrillation.
    The defibrillators in medical centers do not have such limitations since the people using them are trained to interpret an EKG, use other resuscitation modalities etc such that much more likely to have harm from being unable to give a shock rather than giving a shock inappropriately.

    Short answer: No. If there is no breathing, continue rescue breaths. If there is not a pulse, continue external chest compressions. If there is not a shockable rhythm, continue not to shock the heart.

  26. stephend50 says:

    If someone is stating,” I’m clear, you’re clear, all clear!” and then pushes a button on a defibrillator, then this is not CPR. This is Advanced Cardiac Life Support (ACLS) or perhaps Basic Life Support (BLS) with an AED. Strictly speaking CPR is rescue breathing and chest compressions — if you don’t have a pocket mask then it’s just chest compressions.

    During a code, when we are running the PEA algorythm, at the end the senior resident running the code may decide to shock to see if the rhythm is actually fine afib, which can look like PEA. However, normally this is towards the end of a code and we are making sure we didn’t miss anything; about the same time people start suggesting pericardiocentesis and placing 16 ga angiocaths in the chest.

    CPR and defibrilaltion is really only successful for ventricular fibrillation and pulseless ventricular tachycardia arrests. Pulseless electrical activity — PEA arrest — and asystole are dead people unless you can reverse the process that made them have PEA; e.g. volume expansion in the penetrating trauma patient, decompression of tension pneumothorax, removal of fluid from around the heart in tamponade, etc. The reversible causes are known as the T’s and H’s.

    As a hospitalist I have only seen pulseless vtach once, but I have seen lots of PEA arrests. While we do get a pulse and blood pressure back on some of these patients, that does not mean they survive to discharge or do not have some degree of hypoxic brain injury if they do survive. The number we were taught in residency, taking all comers, survivial for cardiac arrest / code in the hospital is some where around 14%.

  27. bluedevilRA says:

    Thank you stephend for answering my question. I know the situation is highly unlikely, but I was just curious if such a situation ever arose where shocks would be used in the absence of a clear indication (such as vtach or vfib) as interpreted by ECG.

    Meanwhile, manixter just gave a condescending reply without even addressing my question. I was clearly talking about doctors or medics running a code and not lay people administering shocks willy-nilly. I am well aware that asystole does not respond to defibrillation, as evidenced by my previous post. My point was to suggest that perhaps in some extreme case, ECG may not be reliably reading the electrical activity of the patient’s heart (which does correlate to their actual heart beats), and thus, would it be wise to administer a shock at the end of the code just in case there is a very fine, undetectable and yet shockable rhythm.

  28. cloudskimmer says:

    “only roughly half survive their initial arrest event. Even fewer (25-33%) survive to discharge from the hospital, and ~75% have a good neurologic outcome.”

    The 75% must be of the 25-33% who survive to discharge? Or is it of the half who survive the initial arrest event?

    Thanks for the great article. It leads to more questions about the propriety of requesting a DNR order. (Do Not Resuscitate)

    When a person is elderly (over 85) with numerous medical problems, none of which are directly life threatening or terminal, but which have resulted in a greatly diminished quality of life, is CPR worth the effort when it is unlikely to work, and may result in additional complications, pain, and neurological deficits (brain damage)?

    It would be interesting to investigate outcomes of CPR and AED usage on airplanes. The airline I’m familiar with has trained all Flight Attendants in CPR and equipped all airplanes with AEDs. Was it worth the expense? They show a training videos with a grateful, saved passenger, but that’s an anecdote designed to make people take the training seriously. The downside of the airplane environment is that the cabin altitude is around 7000 feet on a typical flight, meaning less oxygen available, balanced against the availability of AEDs and people trained to use them.

    in the real world, what is the cost/benefit of training huge numbers of people in CPR techniques that are unlikely to work? In a class I took years ago, the instructor urged us to try very hard in cases of younger people with an obvious external reason for heart stoppage (electrical shock, drowning) but not so hard with the elderly with no external cause, who probably had heart disease and were unlikely to survive. Then there’s the question of the person doing CPR acquiring a disease; a nurse once told me that she would never give mouth-to-mouth, and would instead use a resuscitator bag. I note that despite the unlikelihood of survival, you finish by recommending that everyone be trained in CPR. Should we consider these factors when deciding whether to train people, or purchase and maintain equipment in many public places?

  29. cglenn says:

    Interestingly the International Liaison Committee on Resuscitation has not recommended compression only CPR the American Heart Association has gone against the ILCOR recommendations.

    The risk of disease transmission is very low. There have been no cases of HIV or Hepatitis transmission due to CPR. A PDF from ILCOR can be found here on disease transmission

    Another analysis


    Evidence from three studies (LOE1)[Bertrand 2006 p843], (LOE 2)[Saissy 2000 p1523], (LOE 5)[Krischer 1989 p1263],
    fails to consistently show improvement in survival to hospital discharge when compression only CPR (compared to
    conventional CPR) is administered by professionals to adult patients with an out-of-hospital cardiac arrest.

    Evidence from eight human studies (LOE5) in which off-duty EMS professionals could have been reflected in the study
    population [Bohm 2007 2908, Bosseart 1989 pS99, Holmberg 2001 511, Iwami 2007 p2900, Nagao 2007 p920, Van
    Hoeyweghen 1993 p47, Waalewijn 2001 p273, Wik 1994 p195] document consistent improvement in survival to hospital
    discharge when compression only bystander CPR compared to no bystander CPR is administered by trained
    bystanders to patients with an out-of-hospital witnessed adult cardiac arrest.]. From these studies, there is no
    consistent or statistically significant evidence to document that compression only CPR is superior to conventional CPR
    for out-of-hospital witnessed adult cardiac arrest. Although not tested in a formal equivalence trial or non-inferiority trial,
    the evidence does not demonstrate a statistically significant difference between compression only CPR and
    conventional CPR by trained bystanders.
    Evidence from thirteen mathematical/educational studies show reasonably supporting evidence favoring compression
    only CPR.

    Evidence from 16 animal studies documents supporting evidence for compression only CPR in the animal model, but
    has methodological limitations, which limits the application to the human resuscitation condition

    The evidence does not support, compression only CPR in the pediatric, asphyxiated, drowning, airway obstruction,
    unwitnessed, or delayed resuscitation.

    In my opinion in an emergency situation there are many difficult decisions for the rescuer to remember. It is important to make these decisions as easy as possible. One of the reasons 30:2 was chosen for all types of CPR for lay rescuers was that it eliminated having to remember whether to do 15:2 or 5:1. People would be confused and be unwilling perform CPR if they couldn’t remember the proper ratio.

  30. Groovydoc says:

    The downside to vague public knowledge about CPR is that people and family members often have very unrealistic expectations.

    CPR doesn’t fix cancer, copd, heart failure, or most of the other common end of life diagnoses. Yet, if I had a nickel for every time I was told “Of course I want to live,” or “do everything,” or “dad’s a fighter,” I’d own my own tropical island. Strangely, I’ve never once heard the words, “I was there when they coded mom/dad, and I want you to do that for me too.”

    I think CPR courses should spend a bit more time making it clear that in most cases, death is natural, and can be approached with the goal of comfort, rather than “heroic” measures.

  31. overshoot says:

    The inexperienced observer may have trouble distinguishing massive blood loss from minimal blood loss (a little bit might look like a lot).

    Or, in the case of internal loss, even the experienced will have trouble. The most reliable indicator, as always, is when the patient acts like she’s losing blood — never mind where it’s going.

    It would be interesting to investigate outcomes of CPR and AED usage on airplanes. The airline I’m familiar with has trained all Flight Attendants in CPR and equipped all airplanes with AEDs. Was it worth the expense?

    Consider that none of the airlines that I know of carry enough oxygen outside of the cockpit to keep a patient supplied at 15 l/m until the plane is down and can transfer to an ambulance. So you tell me how serious they are about emergency life support.

  32. Sir Eccles says:

    I think there is widespread misunderstanding regarding the AED devices now widely found in public places, restaurants, airplanes, sports stadiums.

    I recall there was an incident on an airplane where someone tried to use the AED and claimed it was faulty when in fact it was probably working fine, it just wasn’t a situation it could treat (I was probably thinking of this story

    AEDs that are found in public are very limited devices. The key words of the acronym are Automated and Defibrillator. You generally place pads on the patient press a button and stand back. Meanwhile the machine checks for fibrillation only if it detects such a condition (and maybe one or two other situations such as tachycardia) does it apply an appropriate shock. If it detects other rhythms it will not shock and cannot be overridden.

  33. TsuDhoNimh says:

    Current criteria for compression-only CPR being used by the local emergency responders, who were among the ones doing the field trials:

    1 – Must be an adult who collapsed on dry land.
    2 – Must NOT be a child, or a drowning victim.

    The airport has had a few lives saved … whoever responds does compression-only until the EMTs get there, or someone brings the AED off the wall.

    @groovydoc … my instructor made it very clear that it was more likely than not to be unsuccessful unless we were “lucky” enough to see the initial collapse and be in an area with fast emergency response times.

  34. MomTFH says:

    I just got ACLS certified last week.

    We were told to do 30:2 on adults until we could intubate them, and were told to only do compressions-only if absolutely necessary.

  35. The Blind Watchmaker says:

    It takes about 30 compressions or so before cardiac output is anywhere near good enough for perfusion of the brain. In the time it takes to break for breaths, this perfusion drops quite a bit and then not increased again until 30 more compressions or so.

    If I ever code, chest compressions only please.

  36. BillyJoe says:

    “You generally place pads on the patient press a button and stand back.”

    Are you certain you have the order correct?

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