Hands-On Defibrillation—The End of “I'm Clear, You're Clear, We're All Clear”?

T he importance of closed-chest compression in maintaining at least a minimum of myocardial blood flow during cardiac arrest has been increasingly recognized. The adverse effect of interruptions of chest compressions on coronary perfusion pressure is immediate and important; Berg et al showed a 40% decrease in cumulative coronary perfusion after a 13-second pause in chest compression. The 2010 American Heart Association Guidelines for CPR and Emergency Cardiac Care specifically advise rescuers to minimize interruptions of chest compressions for checking the pulse, analyzing rhythm, or performing other activities throughout the entire resuscitation, particularly in the period immediately before and after a shock is delivered (class IIA, level of evidence B). In practice, however, an interruption in chest compressions always happens in the period immediately before a defibrillating shock is delivered; to protect the individual performing the chest compressions from inadvertently being incorporated into the current pathway and thereby suffering the possibly lethal passage of electric current, rescuers have long been advised to stop compressions and move away from the patient. The ritual chant “I’m clear, you’re clear, we’re all clear” serves as a mnemonic for this purpose. Although intended to protect the rescuer from harm, interruption of chest compressions and a fall in myocardial perfusion must result, an unintended and undesirable byproduct. Is this practice of “clearing” the patient before defibrillation really necessary? In 2008, Lloyd et al undertook to intentionally put themselves into the current pathway of biphasic shocks administered during elective cardioversion of atrial fibrillation. They wore polyethylene gloves, self-adhesive external electrode pads were used, and the actual current flow through the “rescuers’ ” bodies was measured. The results were noteworthy — none of the rescuers felt the shock, and the current flow through their bodies was minimal, less than the leakage current that typically occurs from electric kitchen appliances. In an editorial that accompanied the article by Lloyd et al, this writer wondered if the American Heart Association should revisit its long-standing admonition to “clear” the patient about to receive a defibrillating shock; eliminating this recommendation would advance the goal of minimizing chest compression interruptions during CPR. The article “Hands-On Defibrillation Has the Potential to Improve the Quality of Cardiopulmonary Resuscitation and Is Safe for Rescuers” in this issue of JAHA, by Neumann et al, continues this discussion. In a porcine model of cardiac arrest, 20 anesthetized swine underwent an initial 7 minutes of electrically induced ventricular fibrillation (VF) followed by CPR (chest compressions and oxygen) beginning after 7 minutes of VF. After 11 minutes of VF, the animals were defibrillated with biphasic shocks delivered through pregelled self-adhesive defibrillation electrodes with nonconductive backing. The swine were divided into 2 groups; “Hands-Off” defibrillation, where the rescuers “cleared” the animal prior to the shock, and “Hands-On” defibrillation, where the rescuers, wearing 2 pairs of polyethylene gloves each, continued chest compressions as the shocks were being delivered. In the “Hands-Off” animals, chest compressions were interrupted for 8.2% of the total CPR time, whereas in the hands-on group, compression interruptions (for rhythm analysis, not for defibrillation) only totalled 0.8% of the total CPR time (P=0.0003). Berg et al emphasized that following an interruption in chest compressions, coronary perfusion pressure does not immediately return to its preinterruption level, but requires several additional compressions to do so. In the Neumann study, a coronary perfusion pressure (CorPP) “restoration time” was defined as the interval from restarting CPR to the moment when coronary perfusion pressure reached its preinterruption level. If after an interruption, the coronary perfusion pressure was not restored to its preinterruption level, the interval from restarting CPR to the next interruption The opinions expressed in this article are not necessarily those of the editors or of the American Heart Association. From the Department of Internal Medicine, Cardiovascular Division, University of Iowa Carver College of Medicine, Iowa City, IA. Correspondence to: Richard E. Kerber, MD, Department of Internal Medicine, University of Iowa College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242. E-mail: [email protected] J Am Heart Assoc. 2012;1:e005496 doi: 10.1161/JAHA.112.005496. a 2012 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley-Blackwell. This is an Open Access article under the terms of the Creative Commons Attribution Noncommercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.