This is the transcript of a talk given at the Northern New England Collegiate EMS Conference held at Dartmouth College in April 2017.
In the United States, unintentional injury is the leading cause of death for people between the ages of one and 40. This includes motor vehicle collisions and all other forms of hitting, or being hit by, objects, large and small. A long, long time ago, in 1970’s and 80’s, the time it took for people to die from trauma was divided into three groups. The first group, about half of the total deaths, was within the first few minutes. These people typically died before EMS could reach them. The next group of about 30% died over the next couple hours, mostly of major bleeding and airway compromise. This was the period of time when they were extricated, transported and delivered to a hospital. The last 20% died over the weeks and months to follow, usually in the hospital.
The trimodal distribution is a hallmark of trauma education borne from research conducted nearly a half-century ago. The picture looks a bit different today.
A lot has happened in the last 34 years. Overall, society is safer. There are now all sorts of regulations in place for safer everything. We lowered the blood alcohol limit for operating a vehicle by half, and another drop is in the works. We have engineered safety systems which prevent accidents and reduce the forces involved with trauma. And we’ve learned a lot about the science of medicine. However, the causes of trauma have changed and unintentional injury is still the number one cause of death.
Today, the deaths occurring within minutes of a traumatic event have increased, likely due to a higher threshold for serious injury and greater severity of injury, while the late period deaths have been nearly eliminated as resuscitation and critical care advancements have lowered the rates of infection and organ failure.
The middle area, deaths within that “golden hour”, remains. Improved 911 systems, quicker response times, and choreographed “scoop-and-run” techniques have been offset by hospitals that are more than a few minutes away, patients that cannot be moved, and or when mass casualty events over-burden hospital resources.
Furthermore, in the U.S. the quality of the trauma care a patient received depends largely on where and when they are injured. Patients in rural areas tend to have a longer journey to the specialized trauma care they require if they make it there at all.
Of the 147,000 trauma deaths in 2014, 30,000, or about 20% of those people could have survived. These deaths were preventable. As we increase the safety of the general population and make great advances in hospital medicine, the burden of preventable death is shifted on to the shoulders of EMS providers. Currently, the number one cause of preventable death in the United States is still uncontrolled bleeding.
The Military Connection
During the last 16 years of warfare, the U.S. Military has learned some hard lessons about the preventable causes of death. We identified the leading causes of preventable death and found simple ways to aggressively treat them. We found that we didn’t need advanced skills or high-level providers in the field to bring down the number of casualties. All we needed were basic skills, quality training, and situational awareness. Today, the percentage of wounded service members who die from their injuries is at the lowest point in recorded wartime history. We have codified these best practices into two systems, one for the military called Tactical Combat Casualty Care or TCCC, and one for civilians called Tactical Emergency Casualty Care or TECC.
In the spring of 2013, I responded to a call for a young Marine who had stepped on a pressure plate explosive. The explosion had torn apart his legs and knocked him unconscious. We landed, and his buddies loaded him into our helicopter. A well-meaning, non-medical person had put two tourniquets on his legs, but there was still a steady stream of brick-red blood flowing from the charred and mangled remains of his legs. As he laid supine on the mesh litter, still in his combat gear, unconscious and bleeding, my partner and I set into a well-practiced routine honed by a decade of combat.
We quickly applied new tourniquets high and tight on the legs and tightened them until the bright red bleeding had stopped. We quickly swept his body for additional major bleeding. I removed his helmet, tilted his head back, and inserted a nasopharyngeal airway into his nose. While I did this, my partner removed the Marine’s body armor and shirt to inspect his chest for wounds and to ensure his respirations were adequate. Working together, we rolled him to inspect his back. As we found the various small wounds where shrapnel had torn into his body, we quickly bandaged them. Finally, we placed a foil blanket and some self-heating pads around the Marine to maintain what little body heat he had left.
This well-rehearsed dance took only a few minutes to complete, but it addressed all the preventable causes of death encountered in our line of work. Similar principles can be applied to civilian practice.
The primary cause of preventable trauma death in the U.S. is uncontrolled bleeding. Trauma is managed with basics.
The Civilian Connection
Around the same time I was treating that Marine in Afghanistan, an ambulance crew here in the States was dispatched for a city worker caught in a trash compactor. The man was operating the large machine when his right leg became trapped. A tooth from the machine ripped a jagged hole in his thigh releasing a torrent of arterial blood. The man quickly removed his belt and wrapped it around his thigh in an attempt to slow the bleeding. Once on scene, the EMTs had trouble accessing the man, who was trying to hold the belt tight but was quickly losing consciousness.
The EMT reached in and placed a commercial tourniquet around the man’s upper thigh, high and tight, with only one hand. The bleeding stopped and the EMT had bought the 20 minutes necessary to free the entrapped man. While rescuers worked, the EMT kept the man warm with a hypothermia wrap.
While the city worker ended up losing his leg due to the significant trauma, he not only survived what was nearly a fatal accident but completed rehab and returned to work for the city.
This scenario was possible because that EMT had been trained to recognize and prioritize life threats. He was able to apply a tourniquet quickly and under stressful circumstances. He recognized the importance of maintaining his patient’s body heat despite the relatively warm temperatures that day.
Preventable death is managed with basic techniques. The better you know the basics, the more advanced you are.
The Trauma Lethal Triad
Let’s get into the science for a moment and talk about the lethal triad. The Lethal Triad is the self-perpetuating combination of hypothermia, coagulopathy, and acidosis. Understanding the underlying principles and complicating factors are important in order to aggressively prevent this deadly spiral.
The Lethal Triad begins with bleeding. But people don’t generally start bleeding without some encouragement, in this case, trauma. Imagine, if you will, driving recklessly fast on a rainy summer night. All of the sudden you lose control of your vehicle and skid off the road, hitting a large tree.
Once someone has been traumatically injured, they are subject to a number of conditions which kick the Lethal Triad into high gear. The windows that were, until recently, keeping the warmth inside your car are now crumbled along the side of the road. You are trapped in your car, traumatically injured, unable to move, and now exposed to the environment. The warm summer rain feels cold on your skin as you wait for help.
Nearly a half hour later the local rescue squad arrives and extricates you from the wreckage. They load you into the ambulance and strip off your wet clothes. They do this because they need to check you for injuries, of which you have plenty. But, when combined with your now significant blood loss, this quickly leads to you being very cold.
The human body produces its own heat in order to operate in the relatively narrow temperature range of 97° to 99° degrees Fahrenheit. Any shift outside this range starts to create physiological effects. Hypothermia increases short-term death and long-term disability by itself. When combined with uncontrolled bleeding it directly feeds back into the deadly cycle of the lethal triad. Heat loss happens in a number of ways, all of which can happen in an ambulance.
First, the rain has made your clothing wet, conducting heat away from your body. As the EMTs cut your wet clothes off, you are now exposed to the convective air currents inside the ambulance. Without the relative insulation of your clothing, your body radiates heat into the surrounding environment. Your wet skin begins losing heat as the water evaporates. The blood vessels close to your skin constrict further as your body now not only compensates for shock from blood loss but also from the cold.
Being cold wreaks havoc inside your body. It causes oxygen to stick to the blood cells and not enter the tissues of the body. It slows down the metabolic processes that generate heat in your body. It constricts blood vessels, reducing blood flow to certain parts of your body. And it interferes with the ability for your body to build clots.
Your body’s primary solution for bleeding is the formation of blood clots. Most minor bleeding can be controlled in a matter of seconds with direct pressure because we can normally form clots very quickly. The process involved is a complicated cascade involving blood components, such as platelets, and clotting factors present in tissues and in your blood. Once your body cools past 95°F your platelets begin to work less effectively. Past 91°F other parts of the clotting cascade begin to fail as well. This all leads to an interruption in the natural formation of clots and, as a consequence, increased bleeding.
As the EMTs assess and treat your injuries in the back of that ambulance, even with the heaters cranked, you begin to shiver.
Meanwhile, as your body becomes anemic from blood loss– as blood is shunted towards the core in order to perfuse vital organs– and as vessels close to your skin constrict due to hypothermia, less oxygen is delivered to the tissues of the body. A systemic lack of tissue perfusion is known as shock. As oxygen supply dwindles, cells switch from the oxygen-based aerobic metabolism to the less efficient anaerobic metabolism. Where before oxygen allowed cells to create plentiful energy while producing the relatively harmless byproducts CO2 and water, now cells are making a fraction of the energy while producing lactic acid as a consequence.
As you begin to shiver, the metabolic demand increases on your muscles, which are already starved for oxygen, which causes them to pump out even more lactic acid. As this acid builds up in your blood, a condition called acidosis, it further hinders the clotting cascade from doing its critically important job of slowing the bleeding.
The MARCH Algorithm
So what can we do to apply some of this science to the practical aspects of managing a trauma patient? Military medics have been using the MARCH algorithm to treat critical patients for nearly a decade. In addition to being a rather clever mnemonic, the system helps medics quickly identify and treat the primary causes of preventable death. Each letter in MARCH stands for a step in the assessment process. This system is similar to– and builds upon– other trauma assessment algorithms, such as the ubiquitous “HABC” and specifically identifies things we can do to improve the outcomes of our patients.
M stands for Massive Hemorrhage. Early control of life-threatening bleeding is the key to improving survival in trauma. The quickest way to control bleeding from an extremity is with the use of a tourniquet. There are many myths surrounding the use of tourniquets including that they should only be used as a last resort. Current evidence-based medicine has busted most, if not all of these myths. But if you are still on the fence about tourniquet use there are lots of great resources available through federal programs such as Stop the Bleed and national medical organizations such as NAEMT and the American College of Surgeons.
One of the keys to successful tourniquet application is to place the tourniquet “high and tight” on the affected limb. Later on, during a thorough head-to-toe exam when you can determine the extent of the wound, you can place a tourniquet lower and over the skin. But, when seconds count, it is better to place it where you know it will be effective. If the first tourniquet you place doesn’t stop the bleeding, place a second tourniquet right next to it. Make sure there is no gap between the two.
Not all bleeding is going to be manageable with tourniquet application. If you find a wound gushing blood in a place where a tourniquet cannot reach, use any material at hand to pack the wound tight. It is very important to hold good pressure over the packing for several minutes.
Keeping the blood in the body is the first and best way to avoid entering the vicious spiral of the lethal triad.
A stands for Airway. Conduct a survey of the airway. With the adoption of restricted spinal motion protocols in civilian EMS, we now know that with the application of common sense we can manipulate the neck with very little risk of injuring the spine. Use a simple chin lift or jaw thrust to open the patient’s airway and ensure patency. You can then use an airway adjunct to keep the airway open while you move on. The military uses the nasopharyngeal airway almost exclusively because it tends not to stimulate the gag reflex if the patient were to regain consciousness.
If your patient is conscious, you may consider allowing them to assume any position that best protects their airway, to include sitting up. If maintaining consciousness becomes troublesome for the patient, placing them in the recovery position can be very useful in any situation where you have multiple patients.
R stands for Respiration. We want to ensure that the patient is moving air in and out of their lungs, determine whether there is any injury preventing this from happening, and quickly fix those problems.
One of the easily fixable problems we see with thoracic trauma is a penetrating injury into or through the chest. Holes in the chest interrupt the mechanism of breathing. When the diaphragm contracts it creates negative pressure which sucks air in through the nose and mouth to fill the lungs. When there is a hole in the chest wall, air takes the path of least resistance and enters the chest through the hole instead. Instead of the lungs filling with air, the air is sucked in around the lung, collapsing it. This is known as a sucking chest wound. These wounds are easily remedied by quickly covering them with an airtight seal. In the military, we use commercial chest seals with an aggressive adhesive, but any kind of plastic and tape will work. While you prepare a proper chest seal, remember to cover the hole with a gloved hand (it doesn’t have to be yours).
Once you have assessed and, if needed, treated the front of their chest, roll the patient over and assess their back both physically and visually. Make sure to lift all clothing and expose the back completely. By fixing this break in the mechanism of breathing, we help the patient’s blood pick up and transport oxygen to feed tissues and prevent acidosis.
C stands for circulation. At this point, you’ve treated the major causes of preventable death. This is a great time to check your own circulation. Take a deep breath and calm down. Your patient is relying on you to make good decisions now that the bulk of the life saving is done.
Take time to do a thorough head-to-toe physical exam. Check for any unrecognized sources of bleeding. Grab a set of vital signs and start treating for shock. Reassess your patient often.
H stands for hypothermia. Throughout your assessment and treatment, treat your patient’s body heat as you would their blood, keep as much of it in their body as you can. You can do this by minimizing exposure to the environment while you extricate. Once you get them back to your ambulance, replace wet clothing with warm, dry blankets. Crank the heat up even if you are sweating. Use commercially available active heating systems if you can. Or place heat packs around the patient’s neck, armpits, and groin.
When exposing your patients to assess and reassess them, make sure you are exposing them for as little time as necessary and then covering them back up.
Even in the heat of Afghanistan, patients would routinely become hypothermic if not managed aggressively.
Once you’ve completed one cycle through the MARCH algorithm, march back through it again. Recheck your tourniquets to ensure bleeding is still controlled. Reassess the patient’s airway and any adjuncts you inserted. Make sure the patient’s breathing is adequate and unlabored. Check that your bandages are clean, dry, and intact. Monitor temperature and active warming all the way to the hospital.
These steps are taught sequentially but are often practiced simultaneously. The more you are able to practice these assessments and treatments, the more successful you will be when faced with your first major trauma.
We still have quite a ways to go before we reach the goal of zero preventable deaths after injury. But with the battle-tested approach to managing complex trauma that the MARCH algorithm gives us, we will get there.
(2012) Hypothermia and coagulation
(2013) Timing and causes of death after injuries https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603725/
(2014) Ten Leading Causes of Death and Injury https://www.cdc.gov/injury/wisqars/leadingcauses.html
(2015) Trauma Mortality and the Golden Hour
(2010) Changing epidemiology of trauma deaths leads to a bimodal distribution
(2017) Improving Survival from Active Shooter Events: The Hartford Consensus http://bulletin.facs.org/2013/06/improving-survival-from-active-shooter-events/