Standard CPR vs. ACD CPR for Out-of-Hospital Cardiac Arrest

Abstract & commentary

Synopsis: Active compression-decompression CPR administered by highly trained advanced life support personnel increases survival among victims of out-of-hospital cardiac arrest.

Source: Plaisance P, et al. N Engl J Med 1999;341: 569-575.

Devices that allow active compression-decompression (ACD) of the chest have been developed to augment cardiac output during cardiopulmonary resuscitation (CPR). Plaisance and colleagues from France conducted a study testing the hypothesis that ACD CPR would improve survival and long-term neurologic outcome in victims of out-of-hospital cardiac arrest as compared to standard CPR. This report describes data at one year after arrest from their study.

Fifteen mobile ICUs in Paris and Thionville participated in the study. All teams were intensively trained in CPR using both standard and ACD approaches. Physicians were part of the emergency response team. The two CPR methods were used on odd or even days of the month, respectively. All CPR efforts were performed at the scene, not in a moving vehicle. Patients were intubated and ventilated at the start of CPR. Individual rescuers performed either standard closed chest compression or ACD in three-minute shifts to prevent fatigue. Although not specifically stated, defibrillation was apparently used as appropriate.

During the 19-month study period, 1083 calls for cardiac arrest were placed but 333 victims were either pronounced dead before CPR was initiated or were not candidates for resuscitation. Eight patients recovered with basic life support alone. The remaining 750 patients were assigned to either standard (377 patients) or ACD (373 patients) CPR. The two groups were comparable in terms of gender, age, site of arrest, and presence of known cardiac disease. Only 8% of victims received bystander CPR. The time from collapse to initiation of basic life support was 8.9 ± 6.9 and 9.5 ± 7.9 minutes in the standard and ACD CPR groups, respectively. The initial rhythm was asystole in 82%, ventricular fibrillation in 12%, and pulseless electrical activity or other in 6%.

ACD CPR was superior to standard CPR for the following outcome measures: return of spontaneous circulation (39% vs 29%); survival at 24 hours and 7 days (23% and 10% vs 14% and 5%); hospital discharge without neurologic impairment (6% vs 2%); and survival at one year (5% vs 2%). An analysis of the characteristics of the few one-year survivors showed the ACD CPR allowed survival after a longer interval of collapse without CPR and required a shorter duration of CPR for initial resuscitation. Complications were similar with both techniques except for more frequent sternal bruising with the ACD approach.

Plaisance et al conclude that ACD CPR administered by highly trained advanced life support personnel increases survival among victims of out-of-hospital cardiac arrest.

Comment by John P. DiMarco, MD, PhD

One of the major problems of standard CPR is the limited amount of cardiac output and coronary flow provided by the technique. A number of approaches, including the suction device for ACD CPR, described in this paper have been developed. This paper illustrates the amount of improvement we can anticipate with these new approaches.

The French emergency medical system involved in this study differs in significant ways from systems available in many major U.S. cities. In the United States, the major emphasis has been placed on quick response times and early defibrillation by emergency responders. The introduction of automatic external defibrillators has shortened the amount of responder training required. Hopefully, by enlarging the pool of potential rescuers, the time to defibrillation will be shortened and, thus, survival improved. The French system described in this report used a mobile intensive care unit headed by a physician to respond to cardiac arrests. The response time was relatively long and, as a result, many of the victims had asystole or pulseless electrical activity as their initial rhythm. Although only a small proportion were saved, the ACD system provided a significant benefit.

Based on these data, it appears that the ACD system will become a useful secondary tool for emergency response teams. Early defibrillation should still be the first priority. When the initial defibrillation attempts are unsuccessful or if the initial rhythm is asystole, use of ACD CPR may permit salvage of a small number of patients.

The best initial therapy for cardiac arrest is:

a. prompt defibrillation.

b. standard CPR.

c. compression-decompression CPR.

d. IV amiodarone.