Tod Schimelpfenig first reported on ‘Hands-Only CPR’ here in the Wilderness Medicine Blog back in 2008. Two studies just released in the July 2010 edition of the New England Journal of Medicine show that in many cases Compression Only CPR results in similar patient survival rates as Compression and Rescue Breathing CPR. This is especially important in situations where untrained people are giving CPR (or are being coached by 911 dispatchers.

The first study, CPR with Chest Compression Alone or with Rescue Breathing reported “analyses showed a trend toward a higher proportion of patients surviving to hospital discharge with chest compression alone as compared with chest compression plus rescue breathing for patients with a cardiac cause of arrest and for those with shockable rhythms.”

In the second study, Compression-Only CPR or Standard CPR in Out-of-Hospital Cardiac Arrest the results “showed no significant difference with respect to survival at 30 days between instructions given by an emergency medical dispatcher, before the arrival of EMS personnel, for compression-only CPR and instructions for standard CPR in patients with suspected, witnessed, out-of-hospital cardiac arrest.”

It should be noted that compression-only CPR is primarily focused on witnessed arrest scenarios and is not for infants or children and is not recommended in situations such as near-drowning, respiratory failure or drug overdose where rescue breathing is a necessary component.

One of the major sites for this research has been the University of Arizona. The press release that follows expands on their research into this issue. Additional information is available at NPR or you can listen to the NPR Podcast from the link at the bottom of this Blog. You can also watch the Continuous CPR Video from the University of Arizona.

Cardiac Arrest Resuscitation: Passive Oxygen Flow Better than Assisted Ventilation

Arizona researchers have added another piece to the mounting body of evidence that suggests during resuscitation efforts to treat patients in cardiac arrest, “passive ventilation” significantly increases survival rates, compared to the widely practiced “assisted ventilation.”

The study, published in an online edition of Annals of Emergency Medicine, compared the numbers of patients who had suffered a cardiac arrest outside a hospital setting and were resuscitated in the field by Emergency Medical Services personnel. Rescuers used either bag-valve-mask ventilation, which forces air into the patient’s lungs, or facemasks with a continuous flow of oxygen, which work in a similar fashion to those carried on airplanes in case the cabin pressure drops.

Among the 1,019 adult out-of-hospital cardiac arrest patients in the analysis, 459 received passive ventilation and 560 received bag-valve-mask ventilation. Neurologically normal survival after witnessed cardiac arrest with a shockable heart rhythm was higher for the passive oxygen flow method (38.2 percent) than bag-valve-mask ventilation (25.8 percent).

“These results are strikingly similar to earlier observations from Wisconsin, where survival rates went up from 15 percent to 38 percent after paramedics abandoned the official guidelines for the modified protocol that we developed,” says Gordon A. Ewy, MD, a co-author of the study and director of the Sarver Heart Center at The University of Arizona College of Medicine. The Sarver Heart Center’s Resuscitation Research Group developed a modified protocol for treating out-of-hospital cardiac arrest called Cardiocerebral Resuscitation, as opposed to Cardiopulmonary Resuscitation, which should be reserved for respiratory arrest (such as near-drowning or drug overdose).

Under the new concept, first tested in Wisconsin, EMS personnel no longer intubated the patient for ventilation. Instead, they applied a facemask delivering a continuous, low-pressure flow of oxygen.

“Our findings provide compelling evidence that positive pressure ventilation is not optimal in the initial management of out-of-hospital cardiac arrest,” says lead author Bentley Bobrow, MD, emergency physician at Maricopa Medical Center in Phoenix and associate professor of emergency medicine at the UA College of Medicine. “The work from our EMS providers in Arizona further questions the longstanding dogma of tracheal intubation and ventilation for cardiac arrest.

“We are most pleased that while we are helping to advance the science of resuscitation, we are saving more victims of cardiac arrest in Arizona than ever before,” adds Dr. Bobrow, who also is the medical director for the Arizona Department of Health Services Bureau of Emergency Medical Services.

“This study reinforces our belief that survival of out-of-hospital cardiac arrest has more to do with circulating the blood through quality and uninterrupted chest compressions than with ventilation,” Dr. Ewy adds.

EDITORS PLEASE NOTE:
A full-text pdf of the study published in Annals of Emergency Medicine, “Passive Oxygen Insufflation Is Superior to Bag-Valve-Mask Ventilation for Witnessed Ventricular Fibrillation Out-of-Hospital Cardiac Arrest,” is available at https://www.sciencedirect.com  using the search terms “passive oxygen insufflation” and “Bobrow.”

More information about Cardiocerebral Resuscitation is available at https://www.heart.arizona.edu