More than 2,000 years ago, Hippocrates, the father of western medicine, advised men eying a surgical career to join the army to gain experience. His wisdom has held true through ages. “Necessity is the mother of invention,” observes David W. Ross, DO, with Front Range Emergency Specialists in Colorado Springs, Colo., explaining that many advances in trauma management originate on the battlefield. The Boston bombings once again proved the case as modern tourniquets and refined surgical protocols helped to save lives among the nearly 200 victims. Looking forward, imaging will play a key role as the estimated 13 amputees are fitted for prosthetic limbs.
Originally deployed by ancient Greeks to decrease blood loss, tourniquets fell out of favor in the 1980s and 1990s. Although uncontrolled bleeding is a distinct possibility in blast-injured limbs, older tourniquet design posed a double-edged sword as it could damage viable tissue.
“Tourniquets were not standard issue when the Afghanistan and Iraq conflicts began. Soldiers were making due with rubber tubing,” recalls Joseph Blansfield, NP, trauma program manager at Boston Medical Center and chief combat nurse at the 339th Combat Support Hospital in Iraq from 2006-07.
The market responded and makers redesigned tourniquets that are less damaging to normal tissue. Thus, first responders in Boston and elsewhere are equipped withupdated tourniquets, which have been shown to quickly and effectively occlude arterial blood flow and reduce pain scores. “Tourniquets are a difference maker and a life saver,” sums Blansfield.
Medical teams in Boston also adopted new protocols developed on the battlefield, specifically component therapy and damage control surgery, says Blansfield.
Prior to recent conflicts, the conventional transfusion protocol for trauma patients applied a somewhat single-minded goal: re-pressurize the patient’s tank and return blood pressure to 120/80 mmHg. Patients were infused with normal saline or isotonic fluid to replace the lost blood volume. “The problem,” says Blansfield, “is that this didn’t do anything in terms of carrying oxygen or clotting blood. It was an inadequate resuscitation that diluted patients’ clotting ability.”
Component therapy provides patients with what they need: packed red blood cells, which transport oxygen, and fresh frozen plasma to help clotting. “It doesn’t necessarily return the patient’s blood pressure to 120/80, but it brings him or her to the point where organs are perfused, the brain works and urine is produced,” explains Blansfield.
The conventional trauma surgery MO set its sights on completing complex operations, such as vascular anastomosis or liver repair, no matter how long they took. The cliché “the operation was a success, but the patient died,” was all too common. After grueling six- and eight-hour surgeries, patients often faced the trauma triad: hypothermia, acidosis and coagulopathy.
Combat casualty care has ushered in a new era of damage control surgery. “We open whatever compartment is injured, identify the wounds, stop the bleeding and complete the operation in no more than 90 minutes,” says Blansfield. The patient is transferred back to the warm cocoon of the ICU, resuscitated with blood and plasma to reverse the coagulopathy, treat the acidosis and return the physiology to normal. The surgeon completes the operation 24 to 48 hours later, minimizing the trauma to the patient.
|The 3S80 running system was specially designed for above-knee amputees. (Ottobock)|
From acute to chronic crisis
The trauma of the blasts represents the beginning of treatment plans not just for injured victims but also bystanders. “During the next few months, we’ll see much deeper problems than the immediate life or death situation,” predicts Ross.
It’s no secret that blast injuries in the combat zone have resulted in thousands of amputations among wounded warriors. Again, innovation has risen to the challenge, and developments in prosthetics are likely to be transferred to Boston patients.
The historical approach to prosthetic design required a custom cast of the residual limb, explains Kenneth M. Koyle, deputy chief, history of medicine division at the National Library of Medicine in Bethesda, Md. These latex or plaster surrogates took several months to build.
Not anymore. Today, CT and MR images are fed into computer-aided design (CAD) software to accelerate and improve the process of creating the socket and prosthetic model. “Now all we have to do is wait for the swelling to go down and for the incision to heal. As soon as the limb is ready to accept the prosthetic, the patient can have one.”
Researchers have explored bypassing the temporary model completely and developing prosthetic limbs by transferring stump images directly into CAD software. “This has been shown to reduce errors and costs and increase speed,” explains Koyle.
Another development is the “bionic” prosthetic. Ottobock, based in Duderstadt, Germany, developed the C-Leg, a microprocessor-controlled knee joint for transfemoral amputation, in 1997, but the device didn’t take off until the onslaught of amputations among veterans of conflicts in Iraq and Afghanistan. The microprocessor uses accelerometers and sensors to adapt the user’s gait to varying surfaces, providing much more stability compared to the conventional swing joint/locked leg prosthetic model.
Also in the FDA pipeline is the experimental concept of osseointegration. “Instead of a sleeve and socket to hold the limb in place, the prosthetic is attached directly to the bone,” explains Koyle. The advantage is the device becomes part of the skeletal framework, reducing the pressure that a conventional prosthetic places on soft tissue by rubbing against tissue rather than bone. However, the approach requires a connection device that protrudes through the skin, which creates an infection risk.
The experimental technique, which grew from the dental field’s use of implants, is approved for clinical trials in the U.S. “There is a lot of hope that osseointegration will deliver a similar success rate [as implants],” says Koyle.
One final battlefield lesson centers on preparation. Ross’ practice covers the Fort Carson military base. “The mental health requirements have been significant.” PTSD, and related issues such as child abuse, suicide and homicide, affects countless veterans. He cautions that PTSD is not limited to those who personally experienced carnage but also extends to uninjured bystanders. “Based on our experience with returning troops, we are going to see significant psychiatric and psychological issues among [Boston] survivors for years to come,” he predicts.
“Physicians should know how to recognize PTSD, diagnose it promptly and provide the necessary care,” adds Koyle.
The Boston experience proves the value of transferring combat medicine home. And many providers like Blansfield have applied their combat experience to patient care stateside.
Despite the timeless nature of Hippocrates’ advice, modern medicine has outsmarted his instruction on one front, according to Koyle. That is, physicians who choose to serve in civilian life instead of the military can still benefit from the lessons of the battlefield by accessing the latest research and vicarious experience through modern resources like PubMed and PubMed Central.