All you need to read in the other general journalsBMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d5616 (Published 08 September 2011) Cite this as: BMJ 2011;343:d5616
No improvements for CPR after cardiac arrest outside hospital
Two large trials attempted to improve the practice of cardiopulmonary resuscitation (CPR) after cardiac arrest outside hospital, but without success. Ten centres across the US and Canada participated, and in both trials the primary outcome was survival to discharge from hospital without severe disability.
In one study with nearly 10 000 participants, emergency medical staff provided either 30–60 seconds of manual chest compressions and ventilations before the first analysis of heart rhythm or 3 minutes of CPR before first analysis. Previous studies gave conflicting results as to whether manual CPR applied for some time before defibrillation helped or harmed patients. No difference was seen in this study, with 5.9% of people surviving to discharge from hospital without serious disability regardless of the intervention (310/5290 among those who received 30–60 seconds v 273/4643 of those receiving 3 minutes of manual CPR).⇑
The other trial tested an impedance threshold device (against a sham device) added to manual CPR. The device increases negative pressure in the chest cavity, thus increasing venous return and cardiac output. It has been shown to improve short term survival after cardiac arrest outside hospital, but in this trial no effect was seen on the primary outcome, which occurred in 5.8% (254/4373) of patients who received the working device and 6.0% (260/4345) of those who received sham.
Neither trial found an effect on the secondary outcomes, which included survival to admission to hospital, spontaneous return of circulation at arrival to hospital, and survival to discharge from hospital.
Survival rates after cardiac arrest outside hospital have been constant at 7.6% for the past three decades, says the linked editorial (pp 850-1). It seems that the biggest advances in CPR, such …