May 14, 2010

Speeding Ambulances Can Hinder CPR

Korean doctors are suggesting that speeding ambulances might do more harm than good to patients receiving cardiopulmonary resuscitation (CPR).

The researchers monitored how well EMTs performed as the ambulance picked up speed by using a computerized mannequin called Resusci Anne.

The depth and rate of chest compressions both increased, which made researchers worry that EMTs tended to spend less time doing CPR at high velocities.

The exact reasons for the added hands-off time are not understood.  However, what is clear is that during this time no blood gets pumped into the body of a patient in cardiac arrest, starving the brain and other organs of vital oxygen.

At about 37 mph and faster, the extra "no-flow" time amounted to only a few seconds, compared to going 19 mph or slower.  However, Dr. Tae Nyoung Chung, an emergency physician at Yonsei University College of Medicine in Seoul, Korea, said the ambulance was driving on a straight expressway with no traffic lights.

Chung, the leader of the study, told Reuters Health that in real life, sharp turns, stops and bumpy roads would likely exaggerate the effects.

He said based on the findings, which were published in the journal Resuscitation, "there may be a threshold speed between 30 km/hour and 60 km/hour which doesn't increase the portion of hands-off interval while maintaining the speed of ambulance."  He added, "This speed level can be suggested as a speed limit for the ambulance transport with ongoing CPR."

Dr. Dana Edelson, associate chair of the CPR Committee at the University of Chicago, urged caution before slowing down ambulances.  She said that while continuous CPR is crucial to survival, the effects found in the current study were "pretty small."

"The downside of slowing down your ambulance is that it takes longer to get to the hospital," she told Reuters. "We need to be looking for other ways to increase CPR quality."

According to the American Heart Association, one way to increase that quality is for emergency personnel to attempt resuscitation where it happened, instead of rushing the victim off to the hospital.

"Trying to do CPR in the back of an ambulance is not terribly effective," emergency physician Dr. Michael Sayre, a spokesman for the association, told Reuters.

Experts say that it is common practice in both Korea and the U.S.  Some patients go into cardiac arrest during transport, and others might not respond to CPR initially.

Jerry Johnston, a paramedic and the immediate past president of the National Association of Emergency Medical Technicians, said that while few emergency services do moderate ambulance speed when the EMT is doing chest compressions in the back, there are currently no official guidelines.

Johnston told Reuters that mechanical devices which deliver chest compressions dependably already exist, but the price for them is between $10,000 and $15,000 per ambulance.

"Right now the overarching recommendation is that the person driving the ambulance needs to be really cognizant about making the ride smooth so that quality CPR can be performed," he said.


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