A new method of CPR—“active compression-decompression with augmentation of negative intrathoracic pressure”—boosted survival rates for out-of-hospital cardiac arrest from 6 to 9 percent, according to a clinical trial involving 46 U.S. EMS agencies as reported in the Jan. 22 issue of the Lancet.
Manual chest compressions, even when performed well, are inherently inefficient, providing less than 25 percent of normal blood flow to the heart and brain, the study reports. To improve on this, researchers used two hand-held devices to transform the chest into an “active bellows to increase circulation,” according to a news release.
One device uses a suction cup placed on the patient’s chest. After each compression, the suction actively lifts up the chest. A second piece of equipment, called an “impedance threshold device,” is attached to the patient’s airway using a facemask or breathing tube. When the chest is lifted upward, the impedance threshold device prevents air from rushing into the lungs, creat- ing a vacuum inside that helps to move blood into the heart after each compression and to lower pressure in the brain. With each compression-decompression cycle, the heart and brain receive nearly three times more blood flow compared with stan- dard CPR, according to the study.
A total of 813 patients who suffered a non-trauma-related cardiac arrest received standard CPR; another 840 received ac- tive compression-decompression CPR. Patients who received the latter type of CPR were 50 percent more likely to survive to hospital discharge with good neurological function compared to those who received standard CPR (9 percent vs. 6 percent). “For the first time, we have shown that a new method of CPR increases hospital-discharge rates and 1-year survival, which are both associated with good neurological outcomes, by nearly 50%, compared with the current standard of care, closed-chest manual CPR,” wrote the researchers, who were led by Tom Auf- derheide, M.D., a professor of emergency medicine at the Med- ical College of Wisconsin in Milwaukee.
In an accompanying comment, Peter Nagele, M.D., of the Washington University School of Medicine in St. Louis, wrote that while the results are promising, more research is needed before the devices could be recommended for widespread use.
The devices, ResQPump and ResQPOD, are made by Advanced Circulatory Systems in Roseville, Calif. To see a picture, go to advancedcirculatory.com/ResQTrial/ResQTrial-Info.htm.
More Injuries on the Nightshift
Nightshift workers and those who work rotating shifts have nearly twice the odds of being injured on the job than those working regular day shifts, according to a study by Canadian researchers in the January–February issue of the Scandinavian Journal of Work, Environment and Health.
Researchers from the University of British Columbia looked at data on more than 30,000 Canadians. While the overall rate of work injuries decreased between 1996 and 2006, that wasn’t the case for night shift workers. Women, especially, who worked ro-tating shifts were prone to on-the-job injuries, possibly because they have more responsibilities for child care and housework on
their time off, according to a university news release. The number of Canadians working non-standard hours has increased dramatically in recent decades. The number of women in rotating and night shift work increased by 95 percent dur-ing the study period, primarily in health care jobs, according to the study. “As more and more workers become involved in non-day-
time shift work, we may see an increase in injuries, especial-ly among women,” study co-author Chris McLeod, a research associate at University of British Columbia’s Centre for Health Services and Policy Research, said in the release. “Regulatory agencies and employers need to consider policies and programs to help reduce the risk of injuries among shift workers.”
More Shockable Rhythms in Public Than at Home
Cardiac arrests with a shockable rhythm occur much more often in public than at home, says a study in the Jan. 27 New England Journal of Medicine. Researchers looked at records gathered by 208 EMS agencies on almost 12,000 men and women who expe- rienced cardiac arrest in 10 cities throughout the United States and Canada from December 2005 to April 2007.
About 2,042 arrests occurred in public, such as in an airport, sports arena or mall, and 9,564 occurred at home. Seventy-nine percent had a shockable arrhythmia of either ventricular tachy- cardia or ventricular fibrillation (VT/VF), a heart rhythm dis-turbance that can be restored using an AED.
The researchers found there was a two-fold greater chance of having a shockable rhythm in public than at home, and a much greater chance of surviving if the cardiac arrest occurred in public. About 34 percent of those who were shocked by a bystand-er using an AED in public survived to hospital discharge, com-pared to about 12 percent of those shocked at home.
Lead study author Myron Weisfeldt, M.D., speculated that patient demographics and severity of their heart disease likely explain why VT/VF rates are different at home vs. in public. People who go into cardiac arrest at home tend to be older and have other chronic diseases compared to those who are active and attending major sports events, Weisfeldt, a Johns Hopkins cardiologist and past president of the American Heart Association, said in a university news release.
Also, large public venues tend to be where there’s the greatest chance of finding an AED and someone who knows how to apply it.
“Our research clearly shows that the chances of surviving a shockable cardiac arrest are best when someone publicly witnesses it happening, a bystander uses CPR to keep blood flowing to the brain and other key organs and an AED can be applied to electrically restart the heart,” he said in the release.
Researchers say the study is the largest-ever VT/VF analysis. It is part of a landmark series of research projects known as the Resuscitation Outcomes Consortium, which will continue through 2017 and is funded by the U.S. National Heart and Lung and Blood Institute.
Many Bystanders Unwilling to Use AEDs
Most people cannot recognize an AED, and fewer than half would be willing to use one in an emergency, finds a survey of more than 1,000 people from 38 countries. If that’s not bad enough, some of those who say they wouldn’t act have first responder or medical training.
The survey, published online Feb. 3 in the Annals of Emer- gency Medicine, asked people who were passing through a ma- jor train station in Amsterdam questions such as: “If presented with a situation where you could save someone’s life in public with an automated external defibrillator (AED), would you?” The train station is equipped with five public-access AEDs, which enabled the researchers to show participants an AED and ask if they knew what it was.
About 47 percent could correctly identify an AED when researchers pointed one out, and 53 percent said they knew what the device was used for. Only about one-third knew that anyone was allowed to use the device, while 49 percent believed only trained personnel could use it.
About 47 percent said they would be willing to use the AED if necessary, 43 percent said they would not be willing to use the device, and 10 percent were unsure.
A small sample of those surveyed were health care profes- sionals or individuals who had first-response training, according to the study. Of these, around 1 in 4 were unable to identify an AED; about the same number said they would not, or were unsure if they would, use the AED in an emergency.
Reasons given for not using the AED included not know- ing how it works, fear of hurting the victim and worries about being sued.
Researchers say better awareness and training programs are needed to teach more people to use AEDs and to get more people comfortable with the idea of using one.
