The return of tourniquets
Although tourniquets are meant to control life-threatening vascular hemorrhage from extremity wounds, they were long believed to do more harm than good. Complications from improvised tourniquets, including significant tissue damage, limb loss, increased bleeding and mortality, were noted as early as 1916, when the Journal of the Royal Army Medical Corps called them the "invention of the devil."
For much of the century since then, the use of tourniquets was strongly discouraged, both in the military and the civilian pre-hospital setting. Retrospective studies have shown, however, that exsanguination from extremity wounds was the leading cause of preventable death among American casualties in Vietnam and accounted for 7.8 percent of preventable deaths in the first five years of the conflicts in Iraq and Afghanistan. Civilian hospitals, including Boston Medical Center, have reported similar findings.
Attitudes about tourniquets began to change in the 1990s, but the real turnaround came during the later years in Iraq and Afghanistan, explains David S. Morris, M.D., of Mayo Clinic in Minnesota. "One of the biggest threats in Iraq and Afghanistan were roadside bombs, which cause traumatic lower and upper extremity injuries and amputations but aren't as devastating to the torso. Injured soldiers would survive to the aid station, but then couldn't be saved, so the military began using more tourniquets. And what they found was that the type of tourniquet dramatically affected outcomes."
The tourniquets that proved effective were commercial devices, especially the Combat Application Tourniquet (C-A-T), which many studies have found to safely and effectively occlude blood flow with a low incidence of adverse events.
Beginning in 2004, the U.S. Army Institute of Surgical Research began studying mechanical tourniquets. A paper detailing the benefits of the tourniquets and strongly advocating their use appeared in the February 2008 issue of the Journal of Trauma Injury, Infection, and Critical Care. Since then, C-A-T devices have become standard military issue and all soldiers are trained to use them.
C-A-Ts have also made the transition to civilian emergency care. Some police and fire departments now routinely use them in the field, and they were crucial for emergency departments treating Boston Marathon bombing victims. "Those tourniquets are one of the reasons so many people survived," Dr. Morris says. He adds that improvised tourniquets applied at the bomb site were replaced by mechanical ones as soon as patients arrived in hospital emergency departments.
All about C-A-T
The C-A-T has a wide Velcro band and a one-handed windlass system, which tightens the band above a wound. Unlike improvised tourniquets, which act more like a ligature, commercial tourniquets provide true circumferential pressure that completely and consistently impedes arterial blood flow. The windlass is secured in a holder and locked in place with a Velcro tab.
Applying the tourniquet isn't difficult, Dr. Morris says — it's intuitive and comes with printed instructions. Nevertheless, to avoid ischemic and neurological complications, proper use is critical.
Adult tourniquets adjust to fit different limb sizes. Specially sized devices are available for children, and the Southern Minnesota Regional Trauma Advisory Committee has produced a video, available online, showing how to place them.
For both adults and children, the tourniquet should be placed just above the wound — not necessarily on the thigh or upper arm only — and the time of application recorded and submitted to the receiving hospital. If transit time is less than an hour, the tourniquet normally remains in place until the patient is in the operating room. When the transit time is longer and the patient is stable, it may be possible to gradually loosen a tourniquet and leave it unfastened as long as bleeding is completely controlled. Use of another hemostatic bandage may be necessary to augment hemorrhage control, however. If bleeding occurs, the tourniquet is simply re-tightened.
Knowing when tourniquets are medically necessary is equally important. "We tell pre-hospital providers and residents a tourniquet should be used if bleeding can't be controlled with direct pressure, there are multiple wounds or you're in an austere environment and need free hands," Dr. Morris says. Situations in which emergency tourniquets may be necessary include:
- Penetrating trauma from firearms and stabbings
- Terrorist incidents with high-velocity blast injuries to the limbs
- Injuries in rural or wilderness areas where resources are limited and transport to definitive care may be difficult or delayed
- Industrial or farm accidents
Getting the word out
Shortly after the shooting in Newtown, Conn., leaders from medical, law enforcement and fire and rescue agencies published the "Hartford Consensus," a concept paper whose goal was to promote policies that would improve response to mass casualty events. One of the primary recommendations was to place greater emphasis on effective hemorrhage control.
Dr. Morris believes this is a good starting point for a national effort to make mechanical tourniquets readily available in public spaces, including schools. "Tourniquets now have enough presence in the public mind that we should be taking the next step and teaching people when and how to use them," he says, adding that the same educational outreach also applies to hospitals. "In smaller hospitals, where the ED is often staffed with locums, we need to train nurses and pre-hospital personnel. That's a tall order because we work with so many agencies, but it's definitely doable."
Other hemostatic agents
Like mechanical tourniquets, hemostatic gauze and QuikClot dressings were first developed for the battlefield but are now widely used for hemorrhage control in civilian settings.
Hemostatic gauze is embedded with chitosan, a shellfish-derived polysaccharide that actively promotes clot formation. Several types of gauze are available, but in studies, none has proved superior in all circumstances or for all wound types.
QuikClot is a collection of rayon and polyester hemostatic dressings impregnated with kaolin clay. Kaolin has long been known to trigger factors in the blood that initiate the coagulation cascade, resulting in rapid clotting.
"It's pretty dramatic," Dr. Morris says. "We use it for packing the abdomen or for spontaneous hematomas in Coumadin patients."
Dr. Morris is intent on making lifesaving hemostatic agents more readily available and ensuring that people know how to use them." Maybe we can piggyback tourniquet education onto a CPR class or train lifeguards or more paramedics and EMTs," he says.
No matter how you look at it, it's a big undertaking and one that may ultimately be stymied more by a lack of PR than logistics. "Trauma suffers from a lack of good publicity," Dr. Morris admits. "Every cancer, every rare disease that affects far fewer people has a marathon or an armband. Meanwhile trauma, which is the leading cause of death in people under 44, including children, goes unheralded."
For more information
Kragh JF Jr, et al. Practical use of emergency tourniquets to stop bleeding in major limb trauma. The Journal of Trauma Injury, Infection, and Critical Care. 2008;64(2 suppl):S38;discussion:S49.