In summary, many different techniques and devices for chest
compression exist, but direct comparison between them is not
possible, and no single method has been definitively shown to
produce the best outcomes. The most significant confounder of
these trials is the highly variable quality of conventional CPR
technique, which is difficult to quantify, especially in out-ofhospital
resuscitation. Future trials should strive to better characterize
the quality of chest compression delivery in the context
of current CPR guidelines to permit more valid comparison
between studies, as well as to discover the best outcomes that
can realistically be achieved with closed-chest CPR.
If, despite optimizing external chest compression, hemodynamics,
neurological recovery, and overall survival do not
improve, consideration should be given to revisiting open-chest
cardiac massage whenever prolonged resuscitation is expected.