Purdue News

October 17, 1983 Researchers Improve CPR Methods West Lafayette, Ind. – Researchers at Purdue University have developed a new cardio-pulmonary resuscitation method that could save the lives of more heart attack victims. The new method, called Interposed Abdominal Compression-CPR, combines traditional CPR techniques with abdominal compression, forcing blood from the lower part of the body into the heart, says Dr. Charles F. Babbs, a research engineer in Purdue's Biomedical Engineering Center. "A primary concern in CPR is to get oxygen to the tissues," says Babbs. "By forcing more oxygen-rich blood to the heart and brain, we hope to increase the victim's chances for survival." The new method requires two people--one person to compress the victim's chest while the other alternately applies abdominal compression, says Babbs. Though the new technique will not be taught to the public yet, clinical studies are now underway to measure differences in blood-flow and blood pressure between IAC-CPR and standard techniques, he adds. "In almost all cases, we have found an increase in the blood pressure after initiating the modified technique," says Babbs. Studies conducted at Purdue with animals show that the new method can produce twice the blood-flow and twice the blood pressure of standard CPR, he adds. Oxygen intake, essential to successful CPR, increased by 50 percent. If data on human patients show similar improvements, current CPR techniques could be updated to improve victims' chances for survival, says Babbs. However, Babbs urges people not to try the new technique until research on human studies is completed. He expects to obtain results from clinical studies within a year. The research team at Purdue is continuing studies on the IAC-CPR method to see if generalized pressure over the abdomen works better than pressure over the abdominal aorta--a part of major artery leading from the heart. Results from these studies will determine what kind of hand position should be used in the procedure. CPR is used primarily in rescue situations to generate heart and lung action when the heart has stopped, says Babbs. Prompt action is essential because irreversible brain damage can occur within four to six minutes after breathing stops. Babbs hopes to see CPR techniques improved to the point where patients could be sustained for periods of up to one hour. "The percentage of people who receive CPR and survive is low--l0 to 20 percent--with the lowest survival rates in rural areas," he says. "If we could improve CPR to keep the brain alive for periods approaching one hour, many more patients could be saved." The best CPR method for humans has never been worked out, he adds, primarily because of a lack of feedback. "Rescuers need a system to determine the optimal amount of pressure and number of chest compressions to use on individual patients." Though CPR is strongly recommended as a life-saving measure, if done improperly it can cause damage to the heart, liver or other internal organs, puncture lungs or large blood vessels or cause vomiting, warns Babbs. Anyone interested in learning CPR techniques should receive training from a qualified CPR instructor, he adds.   Contact Purdue News Service (765) 494-2096 or purduenews@purdue.edu. To the Purdue News and Photos Page