This JEMS supplement on Intrathoracic Pressure Regulation (IPR) presents current perspectives and data from EMS medical directors and researchers on this non-invasive therapy that improves circulation in cardiac arrest and shock states from a variety of etiologies. Changes in intrathoracic pressure, subtle and invisible to prehospital providers, dramatically affect coronary and cerebral blood flow.
IPR therapy was discovered in 1987 when Keith Lurie, MD, treated a patient resuscitated twice by using a toilet plunger for CPR and survived neurologically intact. This led to the development of the CardioPump, a device that performs active compression-decompression CPR (ACD-CPR). However, studies of ACD-CPR saw mixed results. Subsequent research demonstrated an open airway during CPR eliminated negative pressure created during CPR and that negative intrathoracic pressure dramatically increased when the airway was temporarily blocked during chest wall recoil, improving cardiac preload and coronary artery perfusion. This finding led to the development of the impedance threshold device (ITD) to limit the influx of air during chest-wall recoil to enhance intrathoracic vacuum and perfusion during CPR. Clinical studies have shown increased survival when an ITD is used with an ACD-CPR device and a bundled approach to cardiac arrest. This supplement highlights EMS agencies using a systems-based approach (including the ITD) reporting survival rates above national averages.
The therapeutic concept to enhance perfusion by increasing negative intrathoracic pressure, termed intrathoracic pressure regulation (IPR), drew the interest of NASA and the U.S. military as a treatment for patients suffering from hypotension and shock. The ITD 7 (ResQGARD ITD) was developed to enhance circulation in spontaneously breathing hypotensive patients non-invasively. Use of the ResQGARD has been shown in studies to increase blood pressure by up to 30%. In this supplement, systems using the ITD 7 will share their experiences and data.
Current research and experience with IPR supports its use to enhance perfusion; the more we learn, the more the potential for IPR therapy grows. We’ll explore exciting new areas where IPR therapy is showing an impact.
Our goal is to provide you with an understanding of IPR Therapy and its future potential in this supplement so that you can be more effective in implementing it in the field.