Does Use of an Impedance Threshold Device During CPR Make a Difference?

The goal of cardiopulmonary resuscitation (CPR) is to establish and enhance cardiac output. Therefore, it seems rational that lowering intrathoracic pressure should promote venous return and improve circulation. The impedance threshold device (ITD) prevents inflow of air to the chest during chest recoil without impeding active ventilation and, thereby, prevents intrathoracic pressure from rising. In a cluster-randomized study, 9933 patients with nontraumatic out-of-hospital cardiac arrest at 10 Resuscitation Outcomes Consortium sites in the U.S. and Canada received standard CPR by emergency medical services (EMS) responders with use of an active ITD or a sham device placed within 5 minutes. The study was government funded, and ITDs were sup…