Successful resuscitation rates doubled after upgrade to automated external defibrillators

Aug 18 2004

Successful resuscitation rates more than doubled after the Atlanta VA Medical Center instituted a program of upgrading existing defibrillators and placing automated external defibrillators (AEDs) throughout the hospital, while also educating staff, according to a new study in the Aug. 18, 2004 issue of the Journal of the American College of Cardiology.

“The main, new idea is that our current resuscitation efforts, even in tertiary care hospitals, can be improved by trying new things,” said Samuel C. Dudley Jr., M.D., Ph.D., F.A.C.C., at Emory University School of Medicine and the Atlanta VA Medical Center in Atlanta. “As much as we have come to rely on the ‘code’ system, it has a lot of room for improvement. Secondarily, AEDs work in hospitals, too, not just in places where people may not be as medically sophisticated,” Dr. Dudley said.

Beginning in early 2001, all 68 monophasic defibrillators in the 291-bed hospital were replaced. In high-use areas such as intensive care units, 34 manual biphasic defibrillators that were set to run in automated mode were installed. (A monophasic defibrillator delivers energy in only one direction between the paddles. Biphasic waveforms reverse the electric field during the course of the pulse.) In lower-use areas such as outpatient clinics and chronic care wards, 27 automated external defibrillators (AEDs) were added. These AEDs are similar to the units that are increasingly being placed in public areas. They are designed to be used by people with little or no formal training.

Dozens of workshops, hands-on training sessions, and lectures were held for nurses and physicians at the hospital regarding the role of early defibrillation in CPR (cardiopulmonary resuscitation.)

The researchers, including lead author A. Maziar Zafari, M.D., Ph.D., F.A.C.C., tracked resuscitation statistics before, during and after the defibrillator upgrade program. Between Jan. 1, 1995 and June 30, 2002, there were 569 in-hospital CPR events at the Atlanta VA Medical Center, including 141 events after the start of the program.

The percentage survival of all patients with resuscitation events improved 2.6-fold, from 4.9 percent to 12.8 percent. Looking more closely at the events, the researchers saw that all of the improvement could be attributed to a 14-fold jump in survival to discharge among patients who had no pulse and were experiencing either ventricular tachycardia (VT) or ventricular fibrillation (VF) at the time of CPR.

Dr. Dudley said the results show that hospitals can improve their CPR survival rates.

“I would emphasize that this is a realistic model of a clinical endeavor to improve CPR outcomes in any hospital, by designing a comprehensive program, including intense and continuous educational efforts. Certainly, it is possible to save money on the costs of devices and probably bioengineering support and training by switching many of your current more complicated defibrillators to AEDs. Moreover, the switch is likely to improve patient outcomes. Also, those people still using monophasic devices might consider switching to biphasic devices,” he said.

However, because the program involved more than one type of device, as well as general education about the benefits of rapid CPR, it is hard to be certain which part of the program deserves the most credit for the improvement in survival rates. Also, there may have been other factors that changed around the same time the defibrillator program was instituted.

Despite the possibility that education or other factors may have affected survival rates, Dr. Dudley said this type of program has benefits.

“Following the program we used will save money on devices, is likely to improve patient outcomes and is realistic to implement,” he said.

Dr. Dudley noted that patients who had received a beta-blocker prescription before their CPR events were more likely to survive. He said this apparent benefit may be similar to the link between beta-blockers and reduced risk of sudden death seen in other studies and should be investigated further. Also he urged all hospitals to join the National Registry of CardioPulmonary Resuscitation, in order to provide comprehensive data necessary to make real progress in resuscitation science.

In an editorial in the journal, Jay W. Mason, M.D., F.A.C.C., at Covance Central Diagnostics in Reno, Nev., wrote that the findings may have important implications, but that questions left unanswered by this study make it difficult to recommend specific actions. For instance, Dr. Mason noted that during the study period VA medical centers were changing their client base, reducing the chronic care population in their acute care hospital facilities, which may have affected CPR success rates.

“The extent of improvement in survival from ventricular tachyarrhythmias reported by Zafari, et al, is literally astonishing. In my view the most interesting aspect of the article is to ponder why. My own view is that the change in treatment (use of AEDs and a biphasic shock), could not be the sole or even principal explanation. I suspect that the change in ‘clientele’ at the VA Medical Center is the main explanation,” Dr. Mason said.

He said the challenge is to scientifically prove the true cause of improved survival, before urging widespread changes in hospital practices or equipment.

http://www.acc.org