JEMS.com Editor_s Note: For more on improved CPR rates, check out ˙Groundbreaking Study Doubles SurvivalÓ. For an exclusive look at this study, look for ˙Communities Implement Proven Prehospital Cardiac Arrest Interventions Ó in the November EMS Insider.
CPR has been around since the 1960s. Although it has changed through the decades, the biggest change yet may be on the horizon.
That method is called ˙only rhythmic abdominal compressionsÓ (OAC-CPR), and Purdue researchers found it more efficient than current chest compression CPR, says Leslie Geddes, PhD, Showalter Distinguished Professor Emeritus in Purdue University's Weldon School of Biomedical Engineering.
Abdominal organs hold about a quarter of the total blood volume, and the researchers found in the study (published in the September issue ofAmerican Journal of Emergency Medicine) that pushing the abdomen with the same force recommended for standard CPR (100 lbs. of pressure, 100 times a minute) provided 25% more blood to the heart than the standard method. ˙You can squeeze all of that into the central circulation when you press on the abdomen,Ó Geddes says.
With OAC-CPR, mouth-to-mouth resuscitation isn't necessary because the abdominal compressions expel air from the lungs by depressing the diaphragm up (toward the head). Between compressions, the lungs inhale. This is an important difference from standard CPR, because people -- even medical staff -- are sometimes reluctant to perform mouth-to-mouth ventilation. In a 1993 study, 45% of the 433 doctors and 80% of the 152 nurses polled said they would refuse to administer mouth-to-mouth resuscitation on a stranger.
The idea for the OAC-CPR study began in the 1980s, when Geddes says Purdue doctoral nursing student Sandra Ralston observed that blood flow doubled when abdominal compressions were administered between chest compressions during CPR. Geddes says, ˙So I started thinking, what would happen if you just pushed on the abdomen and eliminated chest compressions entirely?Ó
He created a pressure applicator, described as a ˙scaled-down version of a baseball home plate,Ó that's contoured to compress the abdomen without pushing the ribs. However, he says the procedure can be performed with just the hands.
˙The recent scientific paper Ú was an animal study performed on 11 pigs. The paper alone does not provide sufficient data to prompt a change in AHA's recommendations for performing CPR,Ó an American Heart Association spokesman said. ˙During the development of the 2000 and 2005 ECC guidelines, we evaluated previous studies conducted at Purdue regarding a similar technique called Interposed Abdominal Compressions CPR (IAC-CPR).Ó
When the AHA evaluated IAC-CPR, it concluded, ˙[T]here is insufficient evidence to recommend for or against the use of IAC-CPR in the out-of-hospital setting.Ó