I learned emergency cardiopulmonary resuscitation (CPR) in medical school more than forty years ago and it hasn't changed much until now. It was always hard to do, but now it's half as hard and not as unaesthetic, at least if the results of several studies are taken into account.
The problem was that you had to do two things simultaneously: maintain circulation by chest compression (usually pushing on the sternum) and aerate the mechanically circulated blood by artificial respiration (usually mouth to mouth resuscitation). This meant you stopped compression while inflating the lungs, then resumed it again. Recently the need for artificial respiration has been questioned and now two large scale studies, one in Sweden the other in Japan, have confirmed that compression alone is as good or better than the two together. These studies involved almost 15,000 witnessed cases of out-of-hopsital cardiac arrests and compared outcomes in the two scenarios (compression only and compression with mouth to mouth breathing assist):
"These independent findings confirm what our Resuscitation Research Group and others have found," says Gordon A. Ewy, MD, director of The University of Arizona Sarver Heart Center, where Continuous-Chest-Compression CPR without mouth-to-mouth breathing was pioneered. "To rescue someone who suddenly collapses for no apparent reason, mouth-to-mouth breathing makes no sense."
Shortly before the two latest observational studies were published, Dr. Ewy and his colleagues reported the results of a laboratory study suggesting that cardiac arrest patients face better odds of survival if they receive continuous chest compressions than if treated with standard CPR, in which chest compressions are interrupted by mouth-to-mouth breaths.
"Studies have shown over and over again that four out of five bystanders would not do CPR because of the mouth-to-mouth part," says Dr. Ewy, who has commented on the two new studies in an invited editorial published in the same issue of Circulation. "If people don't have to worry about the so-called rescue breathing, they are much more likely to actually do CPR on someone who needs it. This fact alone is the key to saving more lives. If someone calls the emergency medical services and does nothing, the individual has almost no chance of surviving." (EurekAlert)
These are not the first studies to show this. Previously a paper in The Lancet also concluded you had a better chance of surviving a sudden cardiac arrest if chest only CPR was applied (Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study; Lancet 2007:369:920-926). The reasoning is that there is quite adequate oxygenation in the blood of some with a sudden arrest and that the urgent task is to keep the brain and heart perfused with it as quickly an continuously as possible. Even stopping for a fifteen or twenty seconds can make the difference.
I don't know if this is correct or not (frankly it doesn't sound that plausible to me) but I'm not going to argue with the results. For whatever reason, observations show that if I have a sudden cardiac arrest, you needn't bother to breathe for me. Just keep the blood moving.
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The mouth thing is indeed one reason I wouldnt do it. But it is the sole reason that I have a SPUR bag in each of my cars, two at the airport and three in the house. At 200 apiece I get into the monetary thing of what would I pay to keep a neighbor or family member alive? SPUR's are great because you can hook them to an airway and directly to oxygen, and the bag allows you to breathe for them if someone else is doing chest compressions.
They were primarily bought for Bird Flu as they likely wouldnt have enough ventilators to go around, but family members suited up could breathe for someone pretty easily for one hour stretches.
This is not an ad for them but a discription.
http://66.77.149.134/pdf/RDR/Resuscitators.pdf
You can put in SPUR into a web search and pull up dozens of manufacturers and suppliers. Sure as heck aint going to hurt to have one. I think Revere would concur.
Clear the airway, though.
I think it is impossible to compress the chest without compressing the lung volume, so if regular pulmonary compressions accidentally accomplish shallow respiration, why not stick with K-I-S-S?
"A person whose heart suddenly stops, for example because of a heart attack, was breathing normally only seconds earlier so there is plenty of oxygen in the blood."
Two questions I'm hoping someone might know the answers to:
1) Does this apply in the case of drowning? (since in that case it would seem that oxygen levels would be low)
2) Is only compressions also better than 2-person cpr (in which the pause for breathing is shorter since the rescuer doesn't have to reposition) ?
In 1990, I had a heart attack in the crosswalk of a very busy city street in Portland Oregon. I collapsed unconscious on the street. An unknown physician in a volvo who was three cars back came up an gave me the traditional cpr until an ambulance arrived. The bad news was that my wife was present but not identified by anyone as my wife. The doctor and a nurse there decided between themselves that I was a goner. I had no heart beat and they felt that they were only doing the cpr to on a very remote chance of success. This put my wife in a state of shock that prevented here from remembering how to drive our car to see me at the hospital for several hours.
The ambulance crew immediately jump started my heart and brought me back to a sort of dreamy consciousness. At the hospital they put in some sort of snake and released a chemical to dissolve a clot. They then put in a stent and I have been healthy since then.
I will alway be grateful to that unknown physician. Not, because he saved me from death, but because he saved my family from the heartache and financial deprivation that would have been their lot without me. One must be careful about comments made in a crowd of people.
I am not trying to promote the old style cpr. Just a comment about what the consequences of saving someone's life with cpr might have.
I think the reason is that one of the problems with hypoxia isn't so much the lack of oxygen as it is the free radicals produced when oxygen is reintroduced.
Circulation of the blood allows for nitric oxide to be generated from nitrite in large quantities, and this NO blocks the heme enzymes so they don't produce superoxide when oxygen is readmitted. I think it also allows some ATP generation using nitrite or even superoxide instead of oxygen.
Quite modest amounts of nitrite are very protective in reducing infarct size.
http://www.jci.org/cgi/content/full/115/5/1232
With blood flowing, NO can be generated in regions of low pH and be carried to where it is needed. I think this is the reason for profuse sweating during shock, to deliver ammonia to the normally resident biofilm of ammonia oxidizing bacteria (normal in the "wild" that is) so they deliver nitrite to prevent reperfusion injury. The importance of these bacteria in physiology is what I am studying.
to deliver ammonia to the normally resident biofilm of ammonia oxidizing bacteria (normal in the "wild" that is) so they deliver nitrite to prevent reperfusion injury.
daedalus, I talked with an immensely learned biochemistry guy all the way back in the fabled 1980s, and I asked him at that time to list what he thought the grand challenges were going to be of this decade (the Naughties or the Double-Oughts or what have you), and among the top ten that he listed was: "The detailed physiology of reperfusion".
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We are no where close to understanding that.
A big misconception that is interfering with progress is the myth of "homeostasis" and that restoring "homeostasis" ASAP is the optimal treatment. It isn't. Keeping cells alive, and in metabolic states where they stay alive and don't self-destruct or do "bad things" is the optimal treatment (and is not the same thing). Unfortunately, experiments in extreme physiological states (such as shock, ischemia and reperfusion) are very challenging. There is lots of stuff going on which is not understood, and cells are extremely sensitive to small deviations. What might be good in one state might be bad in another.
The second big misconception is that all radicals are bad. Radicals are very good signaling molecules, and phyisiology uses them all the time. But as a signal you need the right amount in the right place at the right time. Anything else is bad.