The blog of Xeno, a slightly mad scientist
Always check for a pulse first. Chest compressions can fracture ribs. If you are certain there is no pulse, push 100 times per minute with enough force to compress the chest 1.5 to 2 inches. This requires 100 to 125 pounds of force.
Look at a ruler to be sure you know what 2 inches is (most people are wrong about this). Also, try pushing on your bathroom scale to be sure you know what it feels like to press with 125 lbs of force.
Chest compressions alone are as effective in rescuing victims of heart attacks as conventional cardiopulmonary resuscitation that combines compressions with forced breathing, researchers said Wednesday
Studies in Washington and Sweden confirm the growing idea that the breathing component of CPR is necessary only for children and those who have suffered drowning or who have respiratory problems. Recent guidelines based on these and earlier studies may overcome some of the fears of bystanders who are reluctant to initiate CPR because of the danger of infectious diseases.
“These studies reinforce the message that the American Heart Assn. has been promoting since 2008,” said Dr. Michael Sayre, a professor of emergency medicine at Ohio State University in Columbus and a spokesman for the heart association. “When you encounter a person who has collapsed suddenly, the best thing to do is to call 911 and then push hard and fast on their chest. It’s simple, and something anyone can do even if they don’t have any training.”
… Studies in animals have shown that halting chest compressions to blow air into the patient’s mouth reduces blood flow by a startlingly large amount. And the breathing drill, in any case, may not be necessary: For most patients who suffer a heart attack, the blood will contain some oxygen for at least several minutes.
“What we have learned is that continuous blood flow, even if it is not fully [oxygen-] saturated, is probably much better in terms of helping restore spontaneous circulation,” Pepe said. …
This from 2008:
People who collapse suddenly and unexpectedly should receive chest compressions from bystanders, even if the victim gasps in an odd way, new research suggests.
Study author Dr. Gordon Ewy, chief of cardiology at the University of Arizona Sarver Heart Center, and his colleagues reported in Monday’s online issue of the journal Circulation that in more than half of witnessed cardiac arrest cases, the patient gasped.
‘Gasping during cardiac arrest is much better than mouth-to-mouth breathing.’—Dr. Gordon Ewy, U.S. researcherBystanders often misinterpreted gasps or other unusual vocal sounds as normal breathing when it wasn’t, the researchers said.
“Gasping is an indication that the brain is still alive, and it tells you that if you start and continue uninterrupted chest compressions, the person has a high chance of surviving,” said Ewy.
“We need people to promptly recognize sudden cardiac arrest, to call 911 and to start chest compressions right away.”
How much force?
New findings show that the majority of people untrained in how to perform cardiopulmonary resuscitation, and even many trained emergency personnel, do not push with enough force to properly administer CPR.The research tested 104 adults untrained in CPR and 83 firefighters, trained in the procedure. The findings, to be published in the June issue of the journal Cardiovascular Engineering¹, showed that most of the untrained people simply do not apply enough force, said Leslie Geddes of Purdue University, one of the authors of the study.
The success rate for CPR ranges from 5 percent to 10 percent, depending on how quickly it is administered after a person’s heart stops. “This is important because every minute lost in applying CPR results in a 10 percent decrease in successful resuscitation,” Geddes said. “Time is the enemy. After 10 minutes, very few are resuscitated. The American Heart Association recommends pushing with enough force to compress the chest 1.5 to 2 inches, which requires 100 to 125 pounds of force.”…
Try it on a bathroom scale.
The research represents the first time such measurements have been recorded to quantify just how hard people push in a simulated CPR test. The findings showed that 60 percent of the CPR-trained rescue personnel pushed with more than 125 pounds, whereas more than 60 percent of those not trained in CPR failed to push with more than 125 pounds of force.
The people in the study were asked to push on a bathroom scale as though they were performing CPR, and their force was recorded by the scale. “All we are trying to establish is how hard people are able to push in a simulated CPR situation,” Geddes said. “You can’t tell from the data how successful they would have been at resuscitation in a real-life situation.”
Pushing with more than 125 pounds increases the potential for rib fractures. Nevertheless, the chances of survival increase enormously. New guidelines from the American Hearth Association recommend that rescuers performing CPR should “push harder and faster,” Geddes said. “As a result of this recommendation, it’s likely that the resuscitation rate will increase, but it’s equally likely that the fracture rate will increase.” – science daily