Intrathoracic Pressure Regulation for the Treatment of Hypotension

Abstract

Intrathoracic pressure regulation therapy is based upon the physiological principles of the inspiratory impedance threshold device which was developed to increase the return of venous blood back to the heart for treatment of a number of different clinical conditions associated with clinically significant hypotension, including cardiac arrest [1–9]. Intrathoracic pressure regulation therapy works by modulating pressures inside the thorax to augment circulation in states of low blood pressure. This technology was first used in the setting of cardiopulmonary resuscitation (CPR). In the non-spontaneously breathing patient, by harnessing the chest wall recoil with a device that prevents air from entering the lungs each time the chest re-expands after a chest compression, an impedance threshold device (ResQPOD®, Advanced Circulatory Systems, Minneapolis, MN) lowers intrathoracic pressures, enhancing blood return to the heart while lowering intracranial pressures (drop in internal jugular vein pressure). In spontaneously breathing patients, inspiration through a differently configured impedance threshold device (ResQGard®) lowers intrathoracic pressures and similarly enhances cardiac preload and lowers intracranial pressures. Both mechanisms contribute to increases in cerebral perfusion during CPR and in spontaneously breathing patients. Based upon collaborative research with the National Aeronautics and Space Administration (NASA) and the United States Army Institute for Surgical Research, the impedance threshold device has recently been recommended in spontaneously breathing patients for treatment of hypotension due to multiple potential causes, including blood loss, intradialytic hypotension, perioperative hypotension, orthostatic hypotension, and hypotension associated with labor and delivery [10–16].