Introduction
The use of an impedance threshold device (ITD) in cardiac arrest victims has been shown to increase the systolic arterial pressure (SAP) by increasing venous return [1]. There are limited studies concerning the use of ITD in patients with spontaneous respiration and hemodynamic instability. The purpose of this study is to evaluate changes of hemodynamic parameters with the use of ITD in patients with spontaneous respiration and hemodynamic instability.