Wild Iris Medical Education
COURSE PRICE: $6.00
CONTACT HOURS: 1
This course is available until March 1, 2012.
ACCREDITATION / APPROVAL
Wild Iris Medical Education is an approved provider for paramedic and EMT continuing education in California by the Coastal Valleys EMS Agency: CE Provider #49-0057.
This course is appropriate for EMTs, paramedics, and first responders.
The planners and authors of this CE activity have disclosed no relevant financial relationships with any commercial companies pertaining to this activity.
Copyright © 2009 Wild Iris Medical Education, Inc. All Rights Reserved.
Upon completion of this course, you will be able to:
Reports of gunshot wounds are commonplace in many communities across the United States. Nationally in 2005, 30,694 people died from gunshot wounds; 17,002 cases were suicides and 12,352 were homicides. The remaining 1,340 were accidental, police-related, or of undetermined intent. Nearly 70,000 more people received hospital treatment for nonfatal wounds (Wintemute, 2007). These emergency calls are a fact of life for every EMS provider, regardless of service area demographics. The injuries are often devastating and require prompt action, often in a less than ideal situation.
SCENARIO
It’s late evening, midway through a busy shift. Just as you are giving serious attention to the question of whether you “want fries with that,” dispatch information comes through. The address is in a neighborhood well known for its steady supply of penetrating trauma victims. The only information given is: shots fired, unknown number of patients, and police not on scene.
As always, scene safety begins long before the call is dispatched. Units are checked and stocked. Crews should be well rested and alert. They should be familiar with their response area and have reliable maps available. You listen carefully to the dispatch information but remember that it’s only as reliable as the caller.
If there is any indication of violence or if no information is forthcoming, assume the scene to be unsafe. Shut down warning devices early and wait several blocks away until law enforcement can declare the scene safe. If you go in and the scene appears unsafe or becomes unsafe at any point in the call, leave immediately, with or without the patient.
Assume that any scene where there has been injury due to a firearm is also a crime scene. Every service should have protocols concerning command and management of crime scenes and it is imperative to follow them. Approach the scene carefully, noting potential entries and exits, hiding places, and weapons.
Do not take a direct path to the door and remain highly aware of all that goes on around you. Step very carefully and disturb as little as possible without compromising patient care. Determine the number of patients and call for extra resources as needed. Prepare for your initial count to change. Patients may flee the scene while shots are being fired and return once they see the emergency lights.
Be aware that multiple patients may have been on opposite sides of a gun fight. Keep your patients separated and if at all possible send them to different hospitals in separate ambulances. Be aware of bystanders. They may have been part of the fight and may renew it at any time. They may also be friends or family of the patient and may become hysterical or hostile. Do not overlook the fact that your patient may have a weapon as well!
Assume that all firearms are loaded, and do not handle them unless absolutely necessary. Ideally, law enforcement will promptly secure any weapons as soon as they are found. Never lift a gun by inserting an object in the barrel or trigger guard. Everything at the scene has the potential to be evidence.
Carefully note anything that you move or disturb and report it to law enforcement. This includes the patient’s clothing. Do not cut through bullet holes when you remove clothing and do not break the chain of evidence by tossing the clothing aside.
SCENARIO (continued)
Halfway to the call, you receive information that police are on scene, the perpetrator is in custody, and there is one patient who was shot in the arm. As you approach the scene, you note a large law enforcement presence, and the patient sitting on a porch step holding his arm. Closer inspection shows a very distressed teenage male sitting in a large pool of blood. The officer has unloaded a .38 caliber weapon with soft point rounds. The patient tells you he was on his own porch and the shots came from across the street.
The term ballistics refers to the science of the travel of an object in flight (Evans, 2004). In the case of a bullet fired from a gun, this includes its travel down the barrel, its flight through the air, and its behavior once it strikes a target.
In the language of physics, energy is the ability to do work. Work is the displacement of an object. In the case of a gunshot wound, the energy is largely kinetic energy, or energy due to motion. The work done moves tissue in a way that usually causes injury. The kinetic energy of a moving object is a function of its mass and its velocity. The formula for this is, simply:
KE = ½mv2
Note that the velocity is squared. This means that small increases in velocity will cause larger increases in kinetic energy. We know from physics that energy can neither be created nor destroyed. It can, however, change form, often converting to heat or sound. It can also be transferred to another object, including a body, or living tissue. What actually does happen depends in part on bullet design.
The bullet’s travel down the gun barrel is initiated by a powder charge and its velocity is determined largely by the size of the charge. Most handguns fire a bullet at less than 2000 ft/sec and are considered low in velocity. Hunting and assault rifles are considered high in velocity. Magnum charges have more than the usual amount of powder and result in increased velocity. The term rifling refers to a pattern of grooves inside the barrel that causes the bullet to spin in flight. This makes its flight path more stable.
As the bullet travels, it will lose velocity from several factors. The drag from the air will cause it to lose velocity over time. If the bullet’s flight is unstable, subject to yaw or pitch, it will increase the drag and further decrease the velocity. It may also pass through other objects such as walls, windows, or other body parts before reaching its final target.
The bullet’s ability to do damage to a human depends on many factors. These include the velocity of the bullet when it enters the body, the composition and behavior of the bullet, and what tissue it strikes within the body.
Early bullets were nothing but lumps of lead. Lead deforms easily once it strikes an object and, in doing so, transfers kinetic energy well. However, lead also deforms when traveling at high velocity. This makes its path unstable and unpredictable as well as causing it to lose velocity.
Modern developments have addressed this. Encasing a lead bullet in a jacket of hard metal reduces deformation in flight and allows it to travel at a higher velocity. Soft-point and hollow-point bullets are partly jacketed. This allows some increase in velocity but the point will expand on contact. The bullet’s expanded surface area traveling through the body increases the amount of damage it can do. A full metal jacket is primarily used by the military and deforms very little when it strikes the body. It may actually pass entirely through the body with little transfer of energy.
A shotgun blast has its available kinetic energy divided among the multiple pellets. They lose velocity very quickly and will not penetrate the body very far unless shot from close range.
Some bullets are designed to fragment on impact, and the fragments may move off in many directions, causing extensive damage. Other bullets may tumble once they are inside the body; these do extensive damage as they take unexpected paths. The damage is not always on a straight line between the entrance and exit wounds.
Several other things may happen when a bullet enters the body. Tissue crushed by the bullet may create a permanent cavity. Tissue may also be pushed aside, which causes a temporary cavity. This will depend on the bullet and the type of tissue. A bullet that flattens on impact will crush much more tissue than a sharply pointed one that slices through at high velocity.
A bullet may not only fragment itself, but in striking bone it may produce additional fragments. An impact to the body at high velocity also produced a pressure wave, which some believe sufficient to cause traumatic brain injury (Courtney & Courtney, 2007). This is similar to the way in which a primary blast may cause head injury without a direct blow. It is more likely to result from a high-velocity rifle round that tumbles or fragments.
SCENARIO (continued)
Your initial assessment reveals an alert but agitated young man who is protecting his own airway. He is breathing 26 times a minute and has strong pulses centrally. The radial pulse is strong on the left but barely palpable on the right. A single wound high on the right upper arm spurts blood when the patient moves his hand. There is no neurological deficit.
The patient and the officer inspecting the gun agree that only one shot was fired. The patient denies any other pain or injury and has no ongoing health problems. He denies alcohol but admits to “smoking pot” tonight. The chest is stable, his lungs are clear and his abdomen is soft.
The initial assessment begins with a general impression of the patient. Does this patient appear seriously injured or not? Briefly assess mental status. Take any necessary spinal precautions as you evaluate ABCs.
The initial assessment may tell you enough to make a transport decision. The American College of Surgeons has published an excellent flow chart to illustrate the process behind this decision (ACS, 2006). The chart is available at http://crashedu.org/field_triage/2006_decision_scheme_final.pdf. Local protocols always prevail, but many services have used this as a basis for their protocols.
Patients should be taken to a trauma center if they have a Glasgow Coma Score of less than 14; a systolic blood pressure less than 90; or if they are breathing greater than 29 breaths per minute or less than 10 breaths per minute.
Gunshot wounds to the head, neck, or torso call for trauma routing. Gunshot wounds to the extremities qualify for trauma routing if they are proximal to the knee or elbow.
Certain situations also receive consideration for trauma routing. Children and the elderly have poor tolerance for trauma and may decompensate very quickly. Patients with other health history (e.g., bleeding disorders or treatment with blood thinners, end-stage renal disease, advanced pregnancy) will benefit from a trauma center.
At the end of the flow chart is the provision for provider judgment. Look at your patient. If they look “bad” or give you a “bad feeling,” there’s probably a reason you should route them to a trauma center.
These patients should be transported without unnecessary delay on scene. BLS units should request ALS back-up if it is available without prolonging transport time.
The detailed assessment may be done on scene for a stable patient who does not meet criteria for trauma routing. Otherwise, it is done on the way to the hospital once any life-threatening conditions have been addressed. Additional life threats may become apparent during the detailed assessment. If so, they are treated as soon as they are found and the patient is routed to a trauma center if they haven’t already been so designated.
Obtain a SAMPLE history by asking about:
This information can be very helpful in predicting injury patterns, but there should be no delay on scene in order to obtain it. Determine if there was an additional mechanism of injury involved such as a long fall or car wreck.
Use a systematic approach as you would for any assessment. Do not let an impressive injury give you tunnel vision. Take the time to expose the patient’s body and do a complete head-to-toe examination.
Never assume the patient was shot only once. Also realize that some gunshot wounds are subtle and may be overlooked in a hurried or careless examination. The skin is elastic and may close around a small wound. If there was little damage to the vascular system, bleeding may be minimal.
Entrance and exit wounds are not always easy to distinguish. Entrance wounds are generally expected to be smaller than exit wounds. This may be so if the bullet fragments or shatters bone, but it may not always be the case. A shotgun blast may have a devastating entrance wound and no discernible exit. A fully jacketed bullet passing through only soft tissue may show an almost identical entrance and exit wound. A patient shot at very close range may have powder marks on skin or clothing.
Head injuries can be deadly and, even if the patient survives, they can have permanent, devastating consequences. Head-injured patients often require very costly, lifelong care.
Mental status, initial and ongoing, is the single most important for the trauma patient because changes may be the earliest sign of serious injury. Determine whether the patient is oriented to person, place, time, and situation. Do they remember the shooting and what lead up to it? If the patient is unconscious, note any posturing; this is a serious sign.
Your initial assessment of the head should include any obvious wounds, whether due to bullets or another mechanism. Try to determine alcohol or drug use because it may mask or mimic some signs.
Inspect and palpate the scalp for wounds or skull instability. Palpate the facial bones and look at the face for symmetry or swelling. Check the ears for drainage. Assess the eyes for discoloration, foreign bodies, or blood. Check pupil size and reactivity to light. Assess the nose for drainage or bleeding.
Open wounds should be covered, but avoid pressure dressings if there is bony instability. Treat patients with significant head injury as if they also had a spinal injury.
Head-injured patients should receive oxygen. How much oxygen is currently under debate. High-flow oxygen causes vasoconstriction and may reduce swelling in the brain; however, the decreased perfusion can also worsen head injury. Follow your local protocol.
Be prepared to control the airway. Have suction available, as vomiting may occur. Be prepared to assist ventilations if needed. Monitor vital signs. Increasing blood pressure and decreasing pulse may indicate a rise in intracranial pressure. Watch for seizures, document their timing and appearance, and treat according to local protocol.
Consider spinal injury early and take appropriate precautions. Gently take control of the cervical spine and encourage the patient to remain still. Examine for wounds and control bleeding. If the bleeding cannot be controlled with a cervical collar in place, defer the collar. Remember that uncontrolled hemorrhage has a 100% death rate.
Ask about pain and gently palpate for tenderness or deformity before placing a cervical collar. Palpate the spine as you move the patient to a long spine board. Document pulse movement and sensation in all extremities before and after applying an immobilization device.
Any respiratory compromise should prompt you to look for chest injuries. Initial assessment of the chest includes palpation of the chest wall and auscultation of the lungs on both sides. Identify any wounds or major bleeding. These should be sealed as soon as they are found.
During the detailed exam, assess the chest for paradoxical motion. Look for bruising and accessory muscle use. Feel for boney crepitus, the grating sensation when broken bone ends move against each other. Soft-tissue crepitus is a sensation of air bubbles under the skin and can be felt in the chest or neck as a result of air leaking from a punctured lung and getting into the soft tissue. This is a serious finding.
Reassess breath sounds. A patient with penetrating chest trauma may develop a tension pneumothorax (collapsed lung). These patients will have progressive shock and respiratory difficulty. Lung sounds are decreased or absent on the affected side. Tracheal deviation away from the affected side is a late sign and should not be relied on too heavily.
If it is within your scope of practice, needle decompression can be lifesaving. If an open chest wound has been sealed, releasing the seal may also relieve the pressure.
Penetrating chest trauma can also lead to abdominal injuries. Don’t neglect the abdominal exam on a patient shot in the chest. The diaphragm can ride as high as the nipple line. Inspect and palpate the abdomen. Is it firm or soft? Are any masses or pulsations palpable? Check the pelvis for pain, motion, or crepitus. Reassess often. These patients may develop signs of shock very suddenly.
If there is a large open wound with protruding abdominal contents, do not attempt to push them back inside. Cover them with a moist sterile dressing.
Extremity trauma is usually not considered life threatening. Serious hemorrhage is the exception. Severe bleeding should have been controlled in the initial assessment.
Don’t overlook the possibility that the bullet struck a bone and caused a fracture. A splint is appropriate as long as it does not interfere with hemorrhage control.
Some systems allow analgesics to be administered for isolated extremity injuries. Follow your local protocol.
SCENARIO (continued)
The location of the wound and the nature of the bleeding have already determined that the patient will go to the closest trauma center, about 10 minutes away. As the patient has no neurologic deficit and did not fall or undergo any other mechanism of injury, you defer spinal packaging and move the patient to the ambulance for immediate transport.
You place a blood-pressure cuff above the wound and inflate it until the bleeding stops. Then you administer oxygen and place two IV lines. Repeat assessment shows moist, ashen skin that was not apparent before. Blood pressure is 80/40, pulse rate is 120 and weak, both carotid and radial. Respirations are shallow and gasping, 32 breaths per minute.
A good ongoing assessment is not a single action but a continuous process that lasts for the length of the patient encounter. Once the focused and detailed examinations are completed, go back and repeat your initial exam. If the patient is responsive and stable, you are doing this as you converse with the patient.
Patient responses show that they have an airway and a pulse and the pattern of response gives an indication of their mental status and how well they are breathing. For the unstable or unresponsive patient, go back and repeat the steps of the initial assessment at least every 5 minutes.
Repeat and record vital signs. Repeat a focused examination, if indicated. Make sure that oxygen delivery and artificial ventilations are adequate. Do not arrive at the hospital ventilating from an empty oxygen cylinder!
Check dressings to make sure bleeding is controlled. Use the ongoing assessment to re-establish priorities.
SCENARIO (concludes)
Repeat exam of the chest still shows it to be stable with no open wounds; however, lung sounds are absent on the right and you note subcutaneous air in the upper right chest and neck. Needle decompression of the right chest expels the plunger from the syringe and gives rapid relief to the patient.
You place a flutter valve, and repeat vital signs show a blood pressure of 110/80, pulse of 100, respirations 24 and unlabored. Transport concludes without further incident. Chest x-ray in the emergency room shows a simple pneumothorax and a bullet lodged in the right upper chest.
The science of medicine is constantly evolving. New medicines and techniques become available. Tried-and-true methods are scrutinized in the light of new information and may be modified or discarded altogether. Care of the trauma victim is no exception.
Remember that local protocols must always be followed. Those in charge of updating protocols should keep current by whatever means they have available and changes made in an orderly fashion. Street medics should not change their procedures until instructed to do so by their medical director.
One of the first questions on the scene of a serious injury is whether to do anything at all. Death by gunshot wound happens quickly. Of those who die of gunshot wounds, 80% die at the scene or in the emergency room (Wintemute, 2008). Any trauma patient who is pulseless and nonbreathing at the scene has a very small chance of survival. A good DOA policy covers traumatic cardiac arrest and it is essential to follow it.
Spinal restriction has been looked at carefully over the last few years. Immobilization of the head and spine of every trauma patient has been standard practice of most American EMS systems for decades. Only recently has it actually been subject to scientific study, and so far immobilization has not been shown to be effective (Baez & Schiebel, 2006).
Any medic who has tried to do so will tell you that the airway is more difficult to manage if the patient is in a full spinal package. Older adults, in particular, may have chronic deformities that make them unable to lie flat, and the hard board may cause skin breakdown if they have a long wait in a busy emergency room. Anyone who has spent time on such a board in an ambulance or in a classroom will tell you that they are just plain uncomfortable. Remember that we should first do no harm.
Immobilization takes up precious minutes on the scene. In some patients, a 10-minute delay on scene can reduce survival by 10%. One study found that patients with gunshot wounds to the torso had a better chance of survival if they came in by private vehicle rather than by ambulance! The authors suspect that the increased scene time for the EMS-transported patients accounts for this surprising finding. The researchers point out that unstable spinal injuries are extremely rare and they believe that the extra time spent on scene is unwarranted (Cornwell et al., 2001).
Many services are implementing protocol for omission of spinal restriction in carefully prescribed situations. Again, local protocol prevails. Certainly penetrating torso trauma is one situation in which spinal restriction may have more risks than benefits.
There was a time when standard treatment for volume depletion was to start two large-bore lines and run fluids as fast as they could be made to flow. Crystalloids and colloids, isotonic and hypertonic fluids have all had their supporters and detractors. Blood substitutes were brought to clinical trial with great fanfare but the results were disappointing.
Studies suggest that massive volume replacement without adequate hemorrhage control is associated with poor outcomes (Bozeman 2008). This may be due to dilution of clotting factors in the blood. In addition, the increase in blood pressure may disturb newly formed clots.
Hypotension may not be as bad as we once thought. Many protocols now promote the concept of permissive hypotension. Lines are still placed, but fluid is infused judiciously with the goal of maintaining a systolic blood pressure of 80 or 90.
The use of tourniquets has been debated repeatedly over the years and seems to be coming back into style. While we glibly say that all bleeding stops sooner or later, we realized that “sooner” is associated with better patient outcome than “later.” Uncontrolled hemorrhage has a 100% mortality rate, even from extremities. The U.S. military actively promotes the use of tourniquets in combat.
A recent study has shown that pre-hospital personnel with proper education and training can make good decisions about tourniquet use. The neurologic damage and loss of limb that we have been taught to fear did not occur (Kalish et al., 2008). This simple and potentially lifesaving procedure needs to be revisited by protocol committees.
Shootings can be tough calls. Some emergency personnel thrive on the adrenaline rush, but the reality is often an unstable patient with many critical needs that must be met simultaneously. The best approach is a level head, a good knowledge base, and an appropriate skill set coupled with an approach that’s organized, familiar enough to be efficient, and flexible enough to work in the most challenging situation.
American College of Surgeons. (2006). Field Triage Decision Scheme. Retrieved May 8, 2008 from http://crashedu.org/field_triage/2006_decision_scheme_final.pdf.
Baez AA, Schiebel N. (2006) Is routine spinal immobilization an effective intervention for trauma patients? Annals of Emergency Medicine 47(1):110–11.
Bozeman WP. (2008). Shock, Hemorrhagic: Treatment and Medication. Retrieved December 12, 2008 from http://emedicine.medscape.com/article/827930-treatment.
Bradley EM. (2004). Gunshot Wound Ballistics. Retrieved November 21, 2008 from http://www.bcm.edu/oto/grand/02_12_04.htm.
Cornwell EE, Chang DC, Bonar JP, et al. (2001). Thoracolumbar immobilization for trauma patients with torso gunshot wounds: Is it necessary? Archives of Surgery 126(3):324–27.
Courtney A, Courtney M. (2007). Links Between Traumatic Brain Injury and Ballistic Pressure Waves Originating in the Thoracic Cavity and Extremities. Retrieved December 30, 2008 from http://www.ballisticstestinggroup.org/tbipwave.pdf.
Kalish J, Burke P, Feldman J, et al. (2008, August). The Return of Tourniquets. JEMS 44–52.
Wintemute GJ. (2007). Guns, Fear, the Constitution, and the Public’s Health. Retrieved January 7, 2009 from http://content.nejm.org/cgi/content/full/358/14/1421.
