Methodology Score: 4/5
Usefulness Score: 2.5/5
Rubertsson S, Lindgren E, Smekal D, Östlund O, Silfverstolpe J, Lichtveld RA, Boomars R, Ahlstedt B, Skoog G, Kastberg R, Halliwell D, Box M, Herlitz J, Karlsten R.
JAMA. 2014 Jan 1;311(1):53-61.
This large multi-centre randomized controlled trial compared the survival of patients with out of hospital cardiac arrest treated with a standard manual CPR algorithm vs. a mechanical CPR algorithm using an automatic CPR device; no difference is survival was noted. Given the lack of significant difference in the outcomes and the significant cost of the mechanical CPR devices the general consensus was that there would not be a benefit to implementing a mechanical CPR strategy in most circumstances.
By: Dr. Sameer Vakani
(Presented Sept 2014)
The sample size of a clinical trial must be adequately powered to show a minimal clinically important difference (MCID) between the intervention and control arms. MCID is the absolute difference in outcome proportions that would have to be shown by the study intervention for clinicians to accept the new treatment as better. In an effort to keep sample size low, investigators sometimes estimate an MCID much larger than is reasonable or use an outcome that is not the most important, e.g. 4-hour survival rather than survival to discharge.
By: Dr. Ian Stiell