This January 1, 2014 JAMA article studies Mechanical Chest Compressions and Simultaneous Defibrillation vs Conventional Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest There are clearly many factors that affect the chances of survival after a cardiac arrest, including early recognition of arrest, effective cardiopulmonary resuscitation (CPR), timely defibrillation, and postresuscitation care.
One important link is thought to be the delivery of high-quality chest compressions to achieve restoration of spontaneous circulation (ROSC). Even under the best scenarios, the effectiveness of manual chest compressions is thought to provide only 30% of normal cardiac output. Therefore mechanical devices were developed to improve chest compressions. . Prior to this study two small randomized pilot studies (N = 328 and N = 149) found no difference in outcomes of mechanical vs manual out-of-hospital cardiac arrest.
This study looked at whether manual or mechanical CPR would improve 4-hour survival. This Multicenter European study randomized 2589 adult patients with out-of-hospital cardiac arrest. Patients were randomized to receive either mechanical chest compressions (LUCAS Chest Compression System) combined with defibrillation during ongoing compressions (n = 1300) or manual chest compressions and CPR according to guidelines (n = 1289).
Four-hour survival was achieved in 307 patients (23.6%) with mechanical CPR and 305 (23.7%) with manual CPR (risk difference, –0.05%; 95% CI, –3.3% to 3.2%; P > .99). Survival with a CPC score of 1 or 2 occurred in 98 (7.5%) vs 82 (6.4%) (risk difference, 1.18%; 95% CI, –0.78% to 3.1%) at intensive care unit discharge, in 108 (8.3%) vs 100 (7.8%) (risk difference, 0.55%; 95% CI, –1.5% to 2.6%) at hospital discharge, in 105 (8.1%) vs 94 (7.3%) (risk difference, 0.78%; 95% CI, –1.3% to 2.8%) at 1 month, and in 110 (8.5%) vs 98 (7.6%) (risk difference, 0.86%; 95% CI, –1.2% to 3.0%) at 6 months with mechanical CPR and manual CPR, respectively. Among patients surviving at 6 months, 99% in the mechanical CPR group and 94% in the manual CPR group had CPC scores of 1 or 2.
The study concluded that there was no significant difference in 4-hour survival between patients treated with the mechanical CPR algorithm or those treated with guideline-adherent manual CPR. The vast majority of survivors in both groups [also] had good neurological outcomes by 6 months.