It's all about the chest compressions

New CPR advice downplays ventilation.

What do you get when you take the P out of CPR? Although the question sounds like the beginning of a joke, the answer could save the lives of patients in cardiac arrest, according to Jason Persoff, MD, assistant professor of hospital internal medicine at the Mayo Clinic in Jacksonville, Fla.

During a session at Hospital Medicine 2008, held in San Diego in April, Dr. Persoff updated attendees about the latest guidelines and research on advanced cardiac life support, including new CPR guidelines from the American Heart Association (AHA).

As of April 1, the AHA advises and trains laypeople to respond to cardiac arrest by performing only chest compressions. The research on which the group based that recommendation applies to in-hospital arrests as well, Dr. Persoff said.

Underlying the new guidelines is the realization that CPR would be done more effectively if rescuers didn't have to think about both compressions and respiration. “The reason people didn't want to do regular CPR is that they were technically overwhelmed. The same thing happens in the hospital right now,” Dr. Persoff said.

Compression before respiration

A study of inpatient cardiac arrests, published in the Jan. 29, 2005 Journal of the American Medical Association, found that chest compressions were too shallow 63% of the time and too slow 72% of the time, while an August 1993 study published in Resuscitation found that properly done CPR increased survival at 14 days from 4% to 16%.

“There are few interventions in medicine where I can increase your survival fourfold, and this is one of them,” said Dr. Persoff.

His recommendation for applying the findings was simple. “Push hard, pump fast and have good recoil. If you do those three things, you're doing chest compressions well,” he said. Because it's necessary to really put muscle into the pushes, rescuers should be prepared to rotate, he noted. It is, however, important to rotate quickly, as emerging data suggest that even within seconds of stopping compressions, the benefits of good compressions begin to wear off.

The recommendations also mean that the first responders to an arrest should prioritize compressions over bagging the patient, Dr. Persoff said. “The current clinical controversy is should we ventilate at all? We don't know, but we're going to find out because there are a lot of studies ongoing.”

Overzealous bagging, of more than 750 mL tidal volume, can actually harm the patient, Dr. Persoff noted. And according to the current research, patients in an arrest can go about four minutes before the oxygen in their blood is exhausted. “At about four minutes, we do need to start bringing ventilation into the patient, but the first priority should be chest compressions. Delivery of as little as two breaths with every 100 compressions appears to result in better outcomes in patients,” he said.

The other critical factor in CPR is getting it started as soon as possible, since research shows that outcomes drop dramatically after one- or two-minute delays. “We have to empower all the people who are on the resuscitation team and that's everyone, even techs and secretaries. Everyone needs to be able to start chest compressions when a cardiac arrest is identified,” said Dr. Persoff.

Once the code team has arrived, a shock is usually the best bet, even if you can't identify what type of rhythm the patient is in, Dr. Persoff said. “If we spend too much time analyzing what rhythm it is, we spend a lot of time not resuscitating the patient. If you don't know what rhythm the patient is in, treat them like they are in v-fib or v-tach and move on.”

Moving on generally means administering drugs, even though pretty much all of the medications used in advanced cardiac life support—anti-arrhythmics, vasopressin, calcium, atropine, bicarbonate, magnesium—have not been shown to improve survival, Dr. Persoff said.

Research to watch

In new research, beta-blockers and ACE inhibitors appear to have some potential to improve survival of in-hospital cardiac arrest. “They don't appear in the guidelines, so I can't recommend them yet, but keep an eye on it,” Dr. Persoff advised.

Other new research in the area is addressing the question of whether family members should be invited to watch a code on their loved one. Dr. Persoff said yes. “Families that are given an opportunity to witness the cardiac arrest and resuscitation in progress have less pathological mourning [when the outcome is negative], have lower regrets, and tend to be very glad that they did that,” he explained.

It's important to alert the rest of the team that the family will be there, however, so that unrelated conversation is kept to a minimum, Dr. Persoff suggested.

Of course, there's also a reasonable chance that the patient will make it. Dr. Persoff recommended that physicians learn the accurate statistics and review them with patients ahead of time.

“If you are not fluent in the risks and benefits, then a lot of it is left for you to make up as you go. Resuscitation is like any other procedure except that the patient cannot make an informed decision at the time of the arrest,” he said.