Treating Hypotension Using Intrathoracic Pressure Regulation Therapy

The ResQVentTM Intrathoracic Pressure Regulator. (Courtesy photo)

Annually, there are over 11 million diagnoses of hypotension in the U.S. alone. These cases result from a variety of clinical conditions including cardiac arrest, traumatic injury, head trauma, septic shock and post-operative complications. Hypotension and shock resulting from hemorrhage account for 87% of the "potentially survivable" casualties among warfighters, and another 12% of those who have traumatic brain injury result in elevated intracranial pressure.

In light of these statistics, the U.S. Army Medical Research and Materiel Command tasked its Combat Casualty Care Research Program at Fort Detrick, Md., with seeking out ways to lower the casualty figures related to conditions associated with hypotension/hemorrhagic shock. Eliminating or reducing hypotension and elevated ICP as quickly as possible has a life-saving impact on patient outcomes, and the USAMRMC has partnered with Advanced Circulatory Systems, Inc. in order to solve this problem.

The result of this joint effort is Intrathoracic Pressure Regulation technology.

"IPR technology provides a simple, inexpensive, and non-invasive approach for the treatment of several clinical conditions that are common to both military and civilian medical emergencies," said Dr. Sylvain Cardin, portfolio manager for Forward Surgical & Intensive Critical Care within the CCCRP.

"IPR therapy focuses on creating a vacuum inside the chest cavity to enhance circulation, increase blood pressure and lower intracranial pressure," he said. "The vacuum pulls more blood back to the heart from the extremities, resulting in more blood being circulated, and this is actually a huge change from the traditional approach."

Dr. Vic Convertino, a senior scientist at the U.S. Army Institute of Surgical Research located at Fort Sam Houston, Texas, said, "This approach of enhancing circulation to the brain, heart, and other organs by using a small amount of resistance during inspiration to decrease pressure within the thorax is particularly eloquent because it takes advantage of a fundamental relationship between breathing and circulation that naturally exists."

Maintaining a long-standing, successful partnership with the Department of Defense and National Institutes of Health programs, ASCI has been built around a robust product research and development pipeline with both DoD and NIH Small Business Innovation Research funding through ten Phase I awards and eight Phase II awards. The result of this research has been the development of three medical devices designed to enhance circulation to the heart, brain and other vital organs: (1) ResQPOD® for non-spontaneously breathing cardiac arrest patients; (2) ResQGARD® for spontaneously breathing individuals suffering from severe hypotension; and (3) ResQVentTM for patients requiring assisted ventilation.

Launched in 2005, the ResQPOD® has been shown to increase neurologically-intact-survival to hospital discharge rates by 53% in out-of-hospital cardiac arrest patients, in combination with ACSI's CardioPump®. No other technology has had such a transformative and disruptive impact in the field of cardio-pulmonary resuscitation, including a shift in American Heart Association doctrine of training for basic life support from Airway-Breathing-Circulation to the current paradigm of emphasis on circulation through the teaching of Circulation-Airway-Breathing.

"With regard to its military application, the ResQPOD® has been placed on every emergency 'crash cart' at Brooke Army Medical Center, and in the medical kits at the Battalion Aid Stations and air ambulances in the Operation Enduring Freedom theatre," said Cardin. "This device has been shown to save more lives both inside and outside the hospital when used with high-quality CPR."

Released in 2009, the ResQGARD® Impedance Threshold Device is an operationally useful and effective device designed to counteract the effects of severe hypotension and avoid the development of hemorrhagic shock, heat shock, and dehydration in combat casualties until more definitive treatment is available. Historically, over 50% of all battlefield deaths and 87% of potentially preventable deaths are the result of hemorrhage and subsequent circulatory shock.

As with the ResQPODs, ResQGARDs have been placed in medical kits and air ambulances. This technology has proven life-saving benefits as demonstrated by a case of an intervention with this device at a Combat Support Hospital in Iraq with a combat casualty's life-threatening gunshot wound to the pelvis. Events such as this attest to the immediate impact that the ResQGARD® has had on addressing important military needs -- made possible with the support of military funding.

In 2012, ACSI will launch its next generation device, the ResQVentTM, to deliver IPR therapy to the clinical and market segment not served by its existing products, specifically non-breathing patients with TBI or shock in the military and EMS markets. Developed under a DoD SBIR and add-on commercialization pilot program contract, this device lowers elevated intracranial pressure in patients with head injury, and increases circulation and blood pressure in patients with severe hypotension due to multiple causes, including blood loss, sepsis, and cardiac arrest. The ResQVentTM builds upon the physiological breakthroughs achieved with the ResQPOD® and ResQGARD® by harnessing the changes in pressure in the thorax to enhance circulation to the vital organs and lower ICP. It also functions as a lightweight, battlefield-ready, positive-pressure ventilator and continuous positive airway pressure device.

A primary use of the ResQVentTM is for treating one of the most important determinants of outcome from severe head injury, the degree and duration of elevated ICP, which reduces cerebral perfusion pressure and cerebral blood flow. Traumatic head and neck injuries account for 16-33% of all war-related injuries and are a leading cause of mortality upon evacuation to a definitive care setting.

The currently available models of the non-invasive circulatory enhancer technology can be carried and used by multi-level civilian emergency care and military personnel to treat low blood pressure secondary to: (1) hemorrhage, (2) heat shock, (3) dehydration, (4) orthostatic hypotension, and (5) cardiac arrest. The device can also be used by a combat medic to begin resuscitative efforts in situations where establishing intravenous therapy is not possible or practical, and to increase blood pressure to facilitate establishment of intravenous therapy.

"The use of this technical innovation by the U.S. Army on the battlefield, by NASA for post-space flight care, and by personnel in the civilian EMS and acute care markets clearly demonstrates how cooperation between different federal government agencies and private citizens' investment can produce a deliverable product than can make a significant difference in combat theater," said Cardin.

This IPR technology has been recognized nationally with numerous awards, including the 2012 U.S. Army Small Business Innovation Research Achievement Award for "use on the battlefield and during transport for Soldiers with traumatic brain injuries and/or hypotensive emergencies."

"The development of ResQPOD®, ResQGARD® and ResQVENTTM is truly a SBIR success story," said Convertino. "No other technology in the history of the Army SBIR program has received two independent SBIR Achievement Awards for two different life-saving applications."

"It is nice to see what can be accomplished when many agencies come together in a synergistic manner to create a simple, yet very timely and useful, medical device for combat casualty care," said Cardin. "It also shows how basic physiology still has a place in today's high technology world."

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Last Modified Date: 29-Jun-2012