ARTICLE: Stop Randomizing All Cardiac Arrests
AUTHORS: Myron L. Weisfeldt
JOURNAL: Circulation. 2016 Dec 20;134(25):2035-2036.
The field of resuscitation science is characterized nearly uniformly by failed clinical trials: be it sodium bicarbonate, epinephrine at low or high dose, vasopressin, continuous or interrupted chest compressions, temperature management, antiarrhythmic drug use, or devices to augment perfusion, none has been shown convincingly to be of value.
Nearly all of these large expensive trials included victims of cardiac arrest who met entrance criteria and received efforts to resuscitate to the point in time of the intervention. In many of these trials, a subgroup appears to have greater survival in 1 of the arms of the study. Those subgroups are often patients with likely better survival because the arrest is witnessed and a higher frequency of initial shockable rhythm is present. We are then prone to believe the correctness of the benefit in the subgroup and approach guidelines for treatment with these subgroups in mind.
An extensive review and cautionary note on the risks of subgroup analysis when the overall result is null, and the risk of believing borderline statistically significant overall results, has been published recently by Pocock and Stone.1 Even recognizing these concerns, I predict, recent clinical trial subgroup differences will haunt cardiopulmonary resuscitation guideline committees going forward. One example is the recently published study2 of amiodarone, lidocaine, and placebo in refractory ventricular tachycardia or ventricular fibrillation. The overall result showed no statistically significant difference between the individual drugs and placebo, but for the more optimistic subgroup of witnessed cardiac arrest, both drugs were significantly better than placebo. Will the guideline be Class IIb (may or might be reasonable), Class IIa (can be useful or is reasonable), or Class I (is recommended)?
For a link to the full article, click here: http://circ.ahajournals.org/content/134/25/2035.long