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Intrathoracic Pressure Regulator for Blood Loss

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Special rept. Sep 2011-Oct 2013

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Hemorrhagic shock is a leading cause of death in combat, yet potentially survivable with early intervention. This is especially true in patients with head injury. Resuscitative measures, e.g., fluid therapy, can be lifesaving however, delays in intravenous access and differential fluid responsiveness result in over- and under-resuscitation. Intrathoracic pressure regulation ITPR is an emerging technology used to treat hypovolemia and cardiac arrest. Preclinical trials demonstrate that ITPR increases venous return and thereby restores blood pressure and perfusion. We compared the effect of ITPR to placebo in restoring hemodynamics after hemorrhage under general anesthesia. A secondary aim was to determine if ITPR could reduce the fluid burden of hemorrhage. Based on group-to-group comparisons, ITPR had limited effect on improving mean arterial pressure and other hemodynamic responses. However, in some subjects, when ITPR is implemented, improvement in stroke volume, other indices of perfusion, and volume sparing occurs. While fluid resuscitation is the standard of care in hypovolemic hemorrhagic shock, delays in treatment can be potentially fatal. We have shown that there is an increase in the stroke volume and diastolic ventricular compliance using an ITPR in mild hypovolemic subjects. The mechanism of this process is unknown, but is likely due to the increased negative pressure generated throughout the thoracic cavity. In some patients, ITPR could bridge a delay in hemorrhage treatment. Further studies are needed to explore the precise mechanism and whether similar results are achieved.

Subject Categories:

  • Anatomy and Physiology
  • Medicine and Medical Research

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