There is some evidence that use of an impedance threshold device added to active compression-decompression device  may result in small improvement in survival but impedance device added to standard cardiopulmonary resuscitation (CPR) does not improve survival.

Aufderheide TP, et al. Standard cardiopulmonary resuscitation versus active compression-decompression cardiopulmonary resuscitation with augmentation of negative intrathoracic pressure for out-of-hospital cardiac arrest: a randomised trial. Lancet. 2011 Jan 22;377(9762):301-11. RESQ Trial
1,653 adult patients with out-of-hospital cardiac arrest randomized to resuscitation with compression-decompression device plus impedance threshold device compared to standard CPR. RESULTS:  Survival to discharge without neurologic impairment was similar for both groups.

Aufderheide TP, et al. A trial of an impedance threshold device in out-of-hospital cardiac arrest. N Engl J Med. 2011 Sep 1;365(9):798-806. ROC PRIMED Trial
9,220 patients with out-of-hospital cardiac arrest randomized to standard CPR with active impedance threshold device (ITD) compared to standard CPR with sham ITD. RESULTS:  Survival to hospital discharge with normal Rankin score was 6% for the sham ITD group compared to 5.8% for the active ITD group.  Rates for return of spontaneous circulation and survival to hospital admission were also similar for both groups.

Also see Cardiac Arrest (Treatment>Other Management>Prehospital care>Improving chest compressions).  In:  DynaMed

Cabrini L, et al. Impact of impedance threshold devices on cardiopulmonary resuscitation: a systematic review and meta-analysis of randomized controlled studies. Crit Care Med. 2008 May;36(5):1625-32.
Systematic review of older, RCTs

Reviewed JKN 4/14