Objective measurements for guiding initiation, sequencing, and discontinuation of life-support intervention.

At present, there are only a limited number of objective measures available to clinicians resuscitating patients from cardiac arrest. The electrocardiogram and end-tidal CO2 are easily applied, but the data they produce are of only limited utility in evaluating the efficacy of chest compression and in choosing the sequence of therapies. In particular, we are in need of an objective test that can tell us when the myocardium will defibrillate into a perfusing rhythm. The ventricular fibrillation waveform holds information that we have not yet begun to utilize. Parameters derived from power spectrum analysis, such as ventricular fibrillation median frequency, appear promising. Combination of both old and new parameters may allow us to more accurately evaluate the efficacy of therapy.