Improvised explosive devices have made battlefield injuries significantly more difficult to treat in recent decades. Wounds caused by shrapnel, as well as internal injuries caused by the force of the explosion, can prove extremely problematic for medics attempting to stop blood loss, and patients often succumb to bleeding with very little warning, even after receiving treatment intended to curb their loss of blood.
The leading cause of death for trauma patients anywhere in the world is a condition called hemorrhagic shock, which occurs when the body loses more blood than it is capable of compensating for. The reason human beings are able to donate blood safely is because the human body prepares for the potential of severe injury by maintaining a bit more blood that it actually needs to function. This “backup blood” is called the compensatory reserve, and until recently, medical personnel had no way of knowing if a patient’s reserve had been exhausted until it was too late and the body went into shock.
In order to combat hemorrhagic shock, the United States Army’s Institute of Surgical Research has been working for years on a quick and reliable method of measuring a patient’s compensatory reserve, and in turn, getting an advanced warning before blood loss sends the patient into shock. Traditional methods of taking vital signs can only give medics, doctors, and nurses an understanding of how the body is functioning right now, leaving them with no idea of how much longer a patient will last before succumbing to hemorrhagic shock and potentially passing away.
“Our research has revealed that the measurement of the compensatory reserve is the single most important indicator for early and accurate assessment of imminent shock,” said Dr. Victor Convertino, a senior scientist for the U.S. Army Medical Research and Materiel Command Combat Casualty Care Research Program. The compensatory reserve, he added, “represents the body’s ability to adjust for the threat of inadequate oxygen in the tissues due to blood loss.”
Their efforts resulted in the development of tiny device called a CRI (Compensatory Reserve Index). The small box uses an algorithm developed by Army researchers that measures the rate in which a bleeding patient will exhaust their compensatory reserve, or their body’s ability to compensate for blood loss. In effect, it gives doctors an immediate assessment of how long they have to stop a patient’s bleeding. It uses data pulled from the index finger, using the traditional pulse oximeter doctors already use to measure a patient’s pulse rate, making it well-suited for quick adoption in trauma treatment centers on the battlefield and at home.
The device was just cleared by the American Food and Drug Administration for use in hospitals and trauma centers around the world. Soon, emergency rooms and intensive care units will be able to utilize the device to better care for their patients, but more importantly, medics in the field will have a quick and easy means of assessing a patient’s needs. The device was designed specifically to be used by medics and nurses with limited experience in battlefield care to quickly and effectively treat wounded soldiers.
“[The clearance] paves the way for fielding a compensatory reserve measurement device to give combat medics on the battlefield a tool to predict hemorrhagic shock, as well as emergency medical technicians in civilian medical settings,” Convertino said.
“The ability to measure the compensatory reserve continuously and in real-time,” he added, “will revolutionize medical monitoring from early diagnosis of the trajectory toward shock to accurately guiding fluid resuscitation or providing feedback of intervention effectiveness.”
Blood loss is the most common cause of death on the battlefield, and this device could revolutionize the way we treat our wounded in a combat environment. By simply placing a sensor on the index finger of a patient, medics will now be able to assess their treatment in real-time. While a medic may normally take action to curb blood loss and have to hope it worked, the CRI will allow them to know immediately if the procedure or dressing effectively stemmed the flow of blood, or if they need to take further action to stabilize a patient before evacuating them.
Image courtesy of the U.S. Army