Home Feature New thinking on resuscitation techniques

New thinking on resuscitation techniques

June 2008

Published in the June 2008 issue of Today’s Hospitalist
Dramatically revised CPR recommendations released earlier this year now call for bystanders who witness an out-of-hospital cardiac arrest to concentrate on performing high-quality, minimally interrupted chest compressions “and not stop to perform mouth-to-mouth resuscitation. Some experts are predicting that those recommendations may portend big changes for in-hospital rapid response and resuscitation procedures.

“It is a 180-degree turn from previous guidelines,” said Daniel Davis, MD, director of resuscitation at the University of California, San Diego (UCSD) Medical Center and founder and director of UCSD’s center for resuscitation science.

The recommendations are part of an American Heart Association (AHA) science advisory published in the March 31, 2008, issue of Circulation. Speaking at the Society of Hospital Medicine annual meeting this year, Dr. Davis underscored the need for hospitalists to take on new resuscitation training and techniques.

Deeper compressions
According to Dr. Davis, you can calculate a patient’s chance of survival based on how much time you spend doing compressions. “If you spend more than 80% of the time in a code doing compressions,” he explained, “patients appear to have a three-fold better chance of neurologically intact survival.”

While physicians believe that they currently meet these guidelines, “the data coming out of hospitals indicate that we’re doing compressions only about one-quarter to one-third of the time,” Dr. Davis pointed out. “We actually are not doing them as often as we think.”

Moreover, he said, two important studies released in the past year show how important the depth of each compression is. Research has shown that it’s particularly critical to allow the chest to spring back up before pressing down again.

When doctors retrain in CPR, Dr. Davis said, they will likely be taught to make compressions more patient-focused, finding the optimal depth and rate for each patient. But the general rule for every patient is to make compressions “deep enough to go all the way down and let the chest spring all the way up. Rescuers can compress as fast as possible, as long as they can maintain adequate depth and recoil.”

Allowing for negative thoracic pressure to pull blood back into the heart and lungs, he said, “seems to be an important piece of this. The focus of the last three or four years has been to slow down and go deeper. Right now, we are going only an inch to 1¼ inches deep and doing 130-140 compressions a minute. Instead, we want to go more than two inches and slow down to closer to 100 compressions a minute.”

And for inpatients, he added, “We have the unique opportunity to add a pressor as soon as possible in the compression cycle to enhance coronary perfusion pressure because most inpatient arrest victims have intravenous access.” His hospital uses a protocol that includes standing orders for nurses to administer pressors prior to a physician’s arrival during a code.

“Pressor administration,” he said, “is one of the first things we should do.”

Highly choreographed defibrillation
The thinking about shockable rhythms is also changing, said Dr. Davis. Hospitals should change their training so physicians, nurses and housestaff can practice proper defibrillation techniques that minimize compression interruptions.

In the past, he explained, physicians typically stopped compressions, analyzed rhythm, consulted with colleagues, backed away from the patient and started to charge the defibrillator. “Forty-five seconds later, the patient was defibrillated,” Dr. Davis said. “Now, you are supposed to deliver the shock within seconds of stopping compressions “and within seconds, be back trying to profuse the chest at what is probably the most critical point in the resuscitation.” Unlike what physicians have previously been taught, “this has to be a highly choreographed event.”

New technology “such as a device that allows “see-through CPR” via a filtered ECG on a defibrillator screen “will make it easier to perform this sequence, he said. That’s because responders will not have to stop compressions to see if the ECG shows a shockable rhythm.

And although studies have also found that the quicker a patient can be shocked after arresting the better, the odds that rapid shock will happen in a hospital aren’t as good as you might think.

Defibrillation times in areas of the hospital outside of telemetry units where defibrillators are immediately available “aren’t much different than in the out-of-hospital setting,” Dr. Davis said. In addition, doctors and nurses in these areas are not as comfortable assessing potential arrest victims and are often reluctant to initiate chest compressions.

“These providers don’t see a lot of arrests and are no more comfortable determining the presence or absence of a pulse than is your next-door neighbor,” Dr. Davis said. “Our training should address this.”

One possibility is to have responders prioritize high-quality chest compressions to keep the heart primed until the defibrillator arrives rather than running for the defibrillator themselves. “But that may be premature,” he said. “We know very little about hospital resuscitation, but early defibrillation still appears to be a top priority, regardless of location.”

Backing off from mouth-to-mouth?
The AHA backed off from its recommendation to add mouth-to-mouth to compressions during bystander CPR, Dr. Davis said. The goal is to encourage laypeople to perform compressions.

Likewise, the importance of ventilation early in resuscitation is being deemphasized. In cases of sudden, witnessed cardiac arrest, patients have “a full tank of oxygen” and can probably go without additional oxygen for 10 minutes or so until a defibrillator can arrive. For many arrests in the hospital, however, that calculation probably isn’t as true.

Dr. Davis predicts that two different CPR protocols may develop: one for sudden, witnessed arrests, and another for patients who may need oxygen when they are found.

But his final piece of advice for hospitalists is this: Think about ways to prevent inpatient arrests in the first place so you’ll have less need to resuscitate at all.

“There is no question that most arrests in the hospital are broadcast for hours before,” Dr. Davis pointed out.

To make his case, he cited a startling statistic: In his institution, 80% of arrest victims in non-ICU areas showed signs of instability that would have met rapid response criteria for a median of five hours before they actually arrested.

“I suspect,” he said, “that you all would find similar rates at your hospital.”

Deborah Gesensway is a freelance writer reporting on U.S. health care from Toronto, Canada.