Chapter 302: Military Medicine

Care for combat casualties is somewhat different from care for civilian trauma casualties, even though many civilian trauma management principles apply, and conversely, some military techniques have been adapted to the civilian sector. The principles of military medical care are applicable to care in civilian mass casualties, in remote settings, for tactical medicine, and in bioterrorism incidents. Civilian emergency medicine should regularly follow military medical advances and adapt as appropriate.

Advanced trauma life support approaches are well applied in a hospital setting, but in combat, how do you function without ancillary staff? What do you do without ready access to a surgical team? How will you manage in the dirt, at night, while engaged with enemy forces? Simple tasks such as obtaining vital signs or auscultating lung sounds are very challenging. Chapters 7, "Bomb, Blast, and Crush Injuries," 8, "Chemical Disasters" and 9, "Bioterrorism," discuss many conditions relevant to the combat situation. Table 302-1 lists the roles of medical care for combat casualties.

Combat situations require a properly supplied aid bag. A blood pressure cuff and central-line kit have little use on the battlefield. Pack one item that serves multiple purposes, rather than two or three items with limited applications. For example, a cravat can be used as a standard field dressing, pressure dressing, or tourniquet or to hang an IV bag, cover a face as a dust mask, protect against sun exposure on head or neck, filter parasites from water, or even clean weapons.

See Tables 302-2 and 302-3 for examples packing list for aid bags. Not all items will be needed or packed in one bag; the nature of the mission, duration, terrain, weather, and other factors guide the packing list. Consider maintaining two or more different packing lists for different purposes (i.e., one for battle injuries and one for nonbattle injuries).

Have a copy of the nine-line medical evacuation request secured to the radio, train on your personal equipment, maintain it, and pack smartly to ensure easy access to critical items.

The body of highly developed, standardized, prehospital combat trauma guidelines designed to address prevenTable causes of death is known as Tactical Combat Casualty Care (TCCC), which is organized into three phases of care: care under fire, tactical field care, and casualty evacuation.

PHASE 1: CARE UNDER FIRE

This first phase of care occurs when the patient and care provider are under effective enemy fire. The medical actions taken are extremely limited: protect the casualty and move him or her to safety. The urge to tend to a casualty must be tempered by situational awareness: return fire, and secure the site before tending to casualties. The application of a tourniquet for massive bleeding is the only intervention typically performed in this phase (also see "Tourniquets," in chapter 254, "Trauma in Adults"). Needle decompression, fluid resuscitation, and cervical spine immobilization are not performed when under fire.

TOURNIQUET APPLICATION

With massive hemorrhage in a combat setting, a tourniquet is the first-line intervention.

Casualties with tourniquets applied before the onset of shock have a survival rate of 94%, but those with tourniquets applied after shock develops have a survival rate of 17%.^1,2

There are a number of basic considerations for tourniquet application.³ A wide tourniquet (at least 1.5 inches wide) causes less soft tissue damage and is more comforTable for the patient. To control hemorrhage from a large vessel, a tourniquet must have a windlass to gain a mechanical advantage when tightening. Tourniquets without a windlass cannot attain sufficient force to stop arterial bleeding. In combat, we use a tourniquet that can be applied with one hand for self-treatment.

Place the tourniquet about 2 inches proximal to the wound. Tighten to greater than arterial pressure, because tightening that exceeds venous but not arterial pressure may increase bleeding. Apply the tourniquet until the distal pulse disappears. If no distal pulse is present on initial evaluation, apply the tourniquet with a force estimated to be greater than the systemic blood pressure. If placement of a single tourniquet does not control bleeding, place a second tourniquet immediately adjacent and proximal to the first.

The U.S. Army Institute of Surgical Research (http://www.usaisr.amedd.army.mil) has identified three 100% effective tourniquets⁴: the Combat Application Tourniquet^® (CAT) (Composite Resources, Rock Hill, SC), the Delfi EMT Pneumatic Tourniquet (EMT) (Delfi Medical Innovations, Inc., Vancouver, Canada), and the Special Operations Forces Tactical Tourniquet (SOFTT). The CAT and SOFTT are both strap tourniquets that use a built-in windlass as the mechanism for tightening (see Figures 254-1 and 254-2). Of these two strap-type tourniquets, the CAT is less painful, easier to use, smaller, and lighter than the SOFTT (59 grams vs 160 grams). The EMT (see Figure 254-3) is wider, less painful, and less likely to induce nerve damage than the strap tourniquets. The EMT weighs 215 grams and, when packaged, is similar in size to the SOFTT. The CAT tourniquet is standard issue to U.S. military personal. The EMT tourniquet is issued for medical evacuation vehicles and role I to III medical facilities. All of these tourniquets are available through the military medical supply system (http://www.usamma.army.mil/).

POSTTOURNIQUET CARE

The safe time limit for tourniquet application and the point at which limb loss becomes ineviTable have not been determined. Tourniquets are routinely left in place for up to 2 hours in the operating room, and this is the basis for the recommendation to remove a tourniquet within 2 hours, situation permitting. It is certain that for every minute of tourniquet application time, the greater is the chance for permanent damage.⁵ At 6 hours with a tourniquet in place, it is probably best not to remove it; at this point, the release of potassium, lactate, myoglobin, and other toxins from a severely acidotic limb into the circulation would likely cause more systemic harm than benefit. There are, however, several cases of limb salvage with tourniquet times greater than 6 hours.⁶ Additionally, keeping a limb with tourniquet cool, but not freezing, may extend the safe application time substantially.

A tourniquet is a temporizing measure. The next step is to convert the tourniquet to an effective pressure dressing, using direct pressure and a basic gauze roll and elastic wraps and/or hemostatic agents, if required. A knee or hand can apply additional pressure to the bleeding site. Once an effective pressure dressing is applied, release but DO NOT REMOVE the tourniquet. If no bleeding occurs, leave the tourniquet in place but with all pressure released. If bleeding recurs, retension the tourniquet to control bleeding.

PHASE 2: TACTICAL FIELD CARE: THE PRIMARY SURVEY

This phase begins once the patient and provider are no longer under effective enemy fire. Conduct a complete primary survey and perform life-saving interventions.

Combat medicine deviates from the universally accepted airway, breathing, and circulation (ABC) algorithm. Massive hemorrhage is the most common correcTable cause of death on the battlefield, and lethal exsanguination can occur in minutes. Airway compromise accounts for relatively few combat deaths, and respiratory difficulties typically progress over time. This is the reason that TCCC recommends the modified primary survey algorithm of MARCH:

• Massive hemorrhage

• Airway

• Respiratory

• Circulation

• Hypothermia prevention/Head injury

After hemorrhage control, the algorithm mirrors the ABC algorithm, with the additional consideration of a closed head injury and hypothermia prevention as primary survey responsibilities. If a problem is noted during any part of the algorithm, it is addressed before moving further down the algorithm.

In a tactical setting, simple parameters such as level of consciousness and pulse strength are indicators of peripheral perfusion. Is the casualty verbally responsive? If yes, you have already gathered critical information: the blood pressure is strong enough to provide a modest level of cerebral perfusion, and the airway is patent. If the soldier's peripheral pulse is weak or absent, level of consciousness is altered, or if not verbally responsive, then immediate intervention is needed before moving down the algorithm.

MASSIVE HEMORRHAGE

Topical Hemostatic Agents If the wound is not amenable to tourniquet use and a pressure dressing is inadequate, use a hemostatic agent (Figure 302-1). The TCCC Committee recommends the following agents: Combat Gauze, Celox Gauze, and ChitoGauze. Combat Gauze (Z-Medica Corporation, Wallingford, CN) uses a zeolite compound impregnated into surgical gauze, which can be easily shaped into any wound. Celox Gauze (Medtrade Products LTD, Electra House, Crewe, UK) is a chitosan-impregnated gauze, as is ChitoGauze (HemCon Medical Technologies, Portland, OR).

To apply any of these gauze-like hemostatic agents, prepare the wound by evacuating excess blood, taking care to preserve any clot that may have formed around the damaged vasculature; pack the hemostatic gauze directly over the site of the most active bleeding; repack or adjust the gauze for optimum placement; use additional hemostatic agent as required. Hold direct pressure for a minimum of 3 minutes, then reassess for bleeding and repack as needed. Secure the hemostatic agent in place with a pressure dressing.

Junctional Hemorrhage Junctional hemorrhage (from the "junctional" anatomic area between the limbs and intracavitary areas of the abdomen or thorax) is difficult to control. Hemorrhage in the axilla and groin is not amenable to tourniquet application and hemostatic agents.⁷ Specialized junctional tourniquets may be beneficial in certain cases. Presently these include the Abdominal Aortic Tourniquet,⁸ the Combat Ready Clamp,⁹ the Junctional Emergency Tourniquet Tool,¹⁰ and the SAM Junctional Tourniquet. Each product has specific directions for application.

Systemic Hemorrhage Control: Tranexamic Acid Tranexamic acid decreases mortality in trauma.¹¹ It is recommended for use in all casualties that require significant fluid or blood products. Tranexamic acid is most effective when given within 1 hour of injury and must be given within the first 3 hours. The dose is 1 gram of tranexamic acid in 100 mL of normal saline.¹²

Prior to the Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage (CRASH) study and introduction of tranexamic acid, recombinant factor VIIa was considered for use by some special operations forces.¹³ The advent of tranexamic acid, with its ease of administration, efficacy, and improved safety profile (the risk of systemic hypercoagulability has always been a concern), has limited the use of recombinant factor VIIa to very specific intraoperative clinical scenarios.

AIRWAY

Airway intervention during the primary survey is similar for both combat and civilian casualties. Less than 1% of combat trauma requires lifesaving airway intervention in the prehospital setting.^14,15

Lack of spontaneous respirations is a grievous prognostic sign. If there are no spontaneous respirations after opening the airway, the casualty is triaged to the expectant category (expected to die) in a mass casualty (MASCAL) situation (defined as more casualties than resources available); if the situation and resources allow, perform advanced airway techniques including cricothyrotomy,¹⁶ supraglottic airway¹⁷ intubation, and mechanical ventilation. If space is limited, cricothyrotomy equipment is the most important.³¹ The threshold for performing a cricothyrotomy during combat should be low. It is critical to confirm placement and firmly secure the airway.

RESPIRATORY/BREATHING

Tension Pneumothorax The nearly universal use of body armor in present combat operations provides critical protection to the chest and upper abdomen, as evident in the 5% to 7% thoracic wound rate, the lowest in U.S. military conflicts.¹⁸ Many combatants are alive today because of the proper use of body armor.

In a tactical setting, the threshold to perform a needle decompression is very low, as most casualties with penetrating chest trauma will have some degree of hemo-/pneumothorax, and even in the absence of tension pneumothorax, needle decompression is unlikely to cause harm. Use the largest and longest catheters available, because catheters are apt to kink or occlude, and the needle will have to penetrate through several inches of muscle and soft tissue to enter the thorax. The TCCC minimum standard is the 14-gauge 3 inch long needle, as any shorter length will often not penetrate through a muscular chest.¹⁹ Also, there are 10- and 12-gauge catheters available in 3-inch lengths that are highly recommended over the standard, universally available 14-gauge catheters because they are even less likely to kink or occlude with patient movement. Two locations are recommended: (1) the second intercostal space, midclavicular line; or (2) the anterior axillary line at the fourth to fifth intercostal space (see chapter 68, "Pneumothorax," for further discussion).²⁰

Penetrating Chest Trauma Penetrating chest trauma with open pneumothorax or sucking chest wounds is common with large injuries to the chest wall. There are many chest seals, including valved/vented and non-valved/vented chest seals. The updated TCCC standard is to use a valved/vented chest seal as the first choice. If not available, then an unvented seal can be used, but the patient will need to be continuously reassessed for the need for possible needle decompression.²¹ Most casualties encountered in a combat setting are bloody and sweaty; applying a chest dressing that actually adheres to the chest is no small accomplishment and requires some skill and proper preparation of the skin. Wipe the skin as dry as possible. Consider using tincture of benzoin or Mastisol to facilitate dressing adherence if it is available and you have the luxury of time.

Chest Tubes Many physicians come into a field environment expecting to perform sophisticated interventions such as tube thoracostomy or thoracotomy at the point of injury. At this phase of tactical field care, do not expect to perform either of these procedures. The casualty is better served if you focus on basic, lifesaving procedures, prepare for immediate evacuation, and leave more sophisticated interventions for the next level of care. The lifesaving intervention for a chest injury is needle decompression; a chest tube is not immediately required. Needle decompression can be as effective as a chest tube in a patient for up to 4 hours if the patient is not subjected to much movement.²² Needle decompression can be repeated as needed.

CIRCULATION

The TCCC mainstays of circulation management are the appropriate use of low-volume resuscitation (also known as hypotensive or hypovolemic resuscitation) and the selection of appropriate resuscitation fluids. The first step is vascular access.

IV Access Smaller-bore IVs (primarily 18-gauge catheters) are preferred in a tactical environment. Large-bore IVs are more appropriate to administer blood products, which typically are not an option at this phase of field care, and 18-gauge catheters are more than adequate to provide fluid resuscitation in a tactical setting. If blood products are available, then a larger-gauge catheter is indicated.

It is critical to firmly secure the catheter in the combat setting. Use a clear adhesive bandage first; then wrap enough tape to ensure that the catheter will hold in place if you were to throw the IV bag. There are also commercially available IV catheters with Velcro wraps that work very well. There is no one right way to secure a catheter, but give due attention to this because vascular access is the lifeline for severe combat casualties.

Intraosseous Access An intraosseous (IO) line is the alternative to IV access. There are a number of IO devices available commercially, designed for different osseous points of access. Nearly universal use of body armor in the modern tactical environment protects the sternum, so this site is ideal for IO access. Provide secure catheter fixation to prevent dislodgement during patient movement. Some devices may require a removal instrument, which you should secure to the patient; without this removal instrument, the catheter must be surgically removed at the next level of care.

Permissive Hypotension/Low-Volume Resuscitation Following the landmark 1994 Ben Taub study²³ and with subsequent extensive supporting research, permissive hypotension is the TCCC standard for treating noncompressible hemorrhage. Noncompressible hemorrhage is bleeding that occurs in any body part or area that cannot be controlled by a tourniquet or other method of compression. In combat injuries, this equates to penetrating wounds of the abdomen, thorax, and possibly junctional areas. This type of bleeding tends to decrease or even clot once the blood pressure has decreased significantly; however, at this low level of blood pressure and tissue perfusion, the casualty will eventually reach a state of irreversible shock. Providing large-volume resuscitation will initially raise blood pressure and perfusion, but it is also likely to "blow out" any formed clot, resulting in immediate rebleeding and further dilution of clotting factors as additional fluid is given to maintain blood pressure. This vicious cycle leads to rapid death.

We attempt to increase the survival time of casualties by maintaining a delicate balance between a blood pressure high enough to provide adequate tissue perfusion but low enough to avoid clot "blow-out" and clotting factor dilution. Current recommendations are to maintain a mean arterial pressure of 60 mm Hg or a systolic blood pressure of approximately 80 to 90 mm Hg.^24,25 A blood pressure of 80 to 90 mm Hg is clinically noted by a normal level of consciousness and a weakly palpable radial pulse.²⁶ Multitrauma patients with a head injury can be difficult to manage. If hypotensive resuscitation is required in a head-injured casualty, try to maintain a systolic blood pressure between 90 and 95 mm Hg.^27,28

Resuscitation Fluid The prehospital resuscitation fluid of choice for combat trauma has changed over the last 10 years of U.S. military conflict. The goals of the TCCC Committee in recommending the appropriate resuscitation fluid are the following:

1. Enhance the body's ability to form clots with platelets, plasma, and red blood cells at sites of active bleeding.

2. Minimize adverse effects (edema and dilution of clotting factors) resulting from iatrogenic resuscitation injury.

3. Restore adequate intravascular volume and organ perfusion prior to definitive surgical hemorrhage control.

4. Optimize oxygen-carrying capacity as much as possible.

The current resuscitation fluid recommendations for a severe hypovolemic shock are as follows, in order of preference:

• Fresh whole blood

• Blood components in a 1:1:1 ratio of packed red blood cells (PRBCs): plasma: platelets

• Blood components in a 1:1 ratio of PRBCs: plasma

• Plasma: freeze-dried plasma or fresh frozen plasma appropriately reconstituted

• PRBCs

• Hextend

• Lactated ringer's or Plasmalyte

Whole-Blood and Blood Component Infusions In the combat setting, prehospital blood transfusion is carried out under specifically approved theater protocols by specially trained and certified providers. For example, several special operations units can give European-produced freeze-dried plasma under an approved protocol.

Fresh whole blood is the TCCC primary resuscitation fluid of choice because it has all the required blood components in their natural state and provides a survival advantage to casualties with severe trauma and shock.^29,30 The use of whole blood in civilian institutions is rare. However, in a battlefield environment, whole blood is often obtained from fellow soldiers known as "walking blood banks" who are the only available blood source. During Operation Iraqi Freedom, 13% of blood transfusions used fresh whole blood.²⁸

All U.S. combatants are tested for human immunodeficiency virus on a regular basis, but not for hepatitis. There is a U.S. Food and Drug Administration–approved rapid test (QuickVue; Quidel Corporation, San Diego, CA) for human immunodeficiency virus and hepatitis B and C that has been used for timely screening (manufacturer reports >98% sensitivity and specificity). All potential donors should be screened for risk, although perceived risk is often outweighed by potential benefit; additionally, all recipients and donors have blood samples sent to the Armed Forces Blood Program for retrospective analysis. The collection kits for fresh whole-blood transfusions are readily available through military medical supply channels. Because whole-blood transfusions are the treatment of choice for severe trauma and shock, we expect future developments in whole-blood storage to increase its availability for resuscitation.

If fresh whole blood is not available, the next preferred choice is plasma, PRBCs, and platelets in a 1:1:1 ratio.^31,32 A unit of plasma is given first, followed by the PRBCs, and then platelets. In addition to PRBCs, the military is now fielding frozen red blood cells and deglycerated red blood cells to augment current supplies of liquid-packed red blood cells.

The next preferred choice is PRBCs and plasma in a 1:1 ratio if platelets are not available.^33,34 Plasma is again given first followed by PRBCs. Advances in warm platelet storage will hopefully increase the availability of platelets in the near future.

If availability of blood products is limited, you may have to choose between PRBCs and plasma alone. There is some debate as to whether PRBCs or plasma alone is best, so product availability is more likely to drive this decision. Although availability of plasma is somewhat limited, some special operations combat medics now carry freeze-dried plasma as compared to PRBCs. The freeze-dried plasma concentrate currently carried by our medics is produced in France and available for use by North Atlantic Treaty Organization countries³⁵; however, the French freeze-dried plasma should only be used to resuscitate casualties who have given prior informed consent, given the theoretical risk for transmission of certain viral diseases. Units that intend to use freeze-dried plasma typically arrange for consent of their soldiers prior to deployment and provide some method of identification for those who give consent and those who do not.

Colloids and Crystalloids If no blood products are available, Hextend (hetastarch in lactated ringer's solution) is recommended. There is no overwhelming evidence supporting the use of crystalloid over colloid in the young, healthy combat trauma casualty; additionally, colloid has a clear advantage from a weight/volume perspective in the prehospital environment, where the medic must carry the fluid on his back. Hetastarch 500 mL provides intravascular volume expansion of 600 to 800 mL. Hextend is potentially protective against multisystem trauma–induced acute respiratory distress syndrome, induces a favorable acid-base balance, and results in less severe coagulopathy.³⁶ Indiscriminate colloid use can have coagulopathic and immunologic effects, but these adverse effects typically do not occur with colloid administrations of <1500 mL.^37,38

If fluid resuscitation requires >1500 mL of colloid, lactated ringer's solution is given next. Initial use of colloids to replenish intravascular volume during resuscitation must be balanced at some point with an appropriate volume of crystalloid to avoid extensive intracellular dehydration. Start with a 500-mL bolus, and repeat the bolus in 30 minutes if there is no clinical response, using pulse strength and level of consciousness to guide the volume infused. Maintain a systolic blood pressure of 80 to 90 mm Hg, but in head injury, a systolic blood pressure between 90 and 95 mm Hg is the goal.

One liter of infused lactated ringer's results in only 200 to 250 mL of intravascular volume expansion; normal saline is not recommended for resuscitation due to the hyperchloremic acidosis it produces.³⁹ Additionally, aggressive resuscitation with saline-based resuscitation strategies is associated with a number of adverse effects, including increased bleeding, acute respiratory distress syndrome, multiorgan failure, acute coronary syndrome, and increased mortality.^40,41,42

Other Resuscitation Solutions Hypertonic saline (7.5% saline) has some benefits in the intensive care setting^43,44,45 but has not been evaluated in combat.⁴⁶ Hypertonic saline is neither commercially available nor Food and Drug Administration approved, and is not an option for use by U.S. Armed Forces.

Hemoglobin-based oxygen-carrying solutions are promising in theory, but at this time, clinical trials are ongoing and no hemoglobin-based, oxygen-carrying solutions are presently approved by the Food and Drug Administration or available on the commercial market.^47,48

Oral Hydration Common practice in the civilian community is for patients to avoid any oral intake because of the risk of aspiration during anticipated surgery. In the combat setting, there are often limited IV fluids available and long waiting times for evacuation or surgical intervention. In the patient with a normal level of consciousness, the risk of aspiration is very low and outweighed by the benefit of maintaining adequate hydration and patient comfort if evacuation is delayed. As such, oral fluid hydration is accepTable for combat casualties in many situations, even if surgery is anticipated at the next level of care. The only contraindication is active vomiting or an altered level of consciousness that increases risk of aspiration. Time to surgery is not an issue in oral provision of clear liquids to combat casualties.⁴⁹

HYPOTHERMIA AND HEAD INJURY

Rewarming a hypothermic casualty can be very difficult, so it is better to prevent than to treat. Under TCCC, we prevent hypothermia by wrapping the patient in a multilayer insulating wrap with a vapor barrier liner.

Closed head injury is one of the final considerations in this modified algorithm. If a casualty has an altered level of consciousness, it is either because of inadequate cerebral perfusion or cerebral injury. If hypovolemic shock has been ruled out or treated and the mechanism is consistent with closed head injury, then treat accordingly. Have the patient recline with the head elevated at 30 degrees. Give oxygen to maintain an oxygen saturation of at least 90%. Maintain a systolic blood pressure of at least 90 mm Hg.²⁶

SECONDARY SURVEY

Expose the casualty as much as the tactical situation will allow. Be prepared to preserve body heat to avoid hypothermia. Stabilize fractures and treat less severe wounds. Continually reassess the casualty. This may seem obvious, but a tactical environment with multiple casualties is chaotic. Do not expect to have an assistant to monitor each casualty or call out periodic vital signs. Attend to the casualties who require intervention, but remember to reassess everyone. This can be as quick as asking a quick question to assess airway, hemodynamic status, and level of consciousness, or quickly palpate a radial pulse to determine rate and strength; obtain blood pressure if possible and if there are concerns about hemodynamic status. The character of the peripheral pulse and the Glasgow coma scale are reliable severity indicators.⁵⁰ Recheck dressings or bandages for continued bleeding.

PAIN CONTROL

Pain control is crucial for facilitating transport and patient comfort. Under TCCC, there are three primary pharmacologic modes of pain control. For lesser injuries with normal mental status, use a combat pill pack. This contains two 500-milligram acetaminophen tablets and a meloxicam tablet. This combination is effective for moderate pain control, does not affect mental status, and is administered orally. Because meloxicam has a favorable side effect profile and no effect on platelet function, it is the TCCC nonsteroidal anti-inflammatory drug of choice.

FENTANYL AND KETAMINE

For more severe pain, we recommended either oral transmucosal fentanyl citrate lozenge, informally known as the fentanyl "lollipop," or ketamine. Oral transmucosal fentanyl citrate provides rapid-onset, long-lasting pain relief for severe pain without the need for an IV. When placed into the buccal fold and slowly sucked on, 25% of the fentanyl is absorbed sublingually, with onset in 15 minutes. The remainder that is swallowed enters the GI tract and loses about 50% of its bioavailability through first-pass effect, but the remaining 50% is slowly absorbed, providing more extended pain relief for the next 4 to 6 hours.⁵¹ An 800-microgram fentanyl lozenge is the recommended starting dose. Rapidly chewing and swallowing the lozenge will decrease the total amount of fentanyl received, because less is absorbed sublingually and more enters the digestive system, which is subject to first-pass effect. Should the casualty swallow the lozenge, he or she is generally not at risk of an uncontrolled fentanyl bolus. To avoid swallowing, the recommended technique is to tape the lozenge to the patient's finger, which will deter swallowing and prevent overdosing should the patient become somnolent (as the lozenge attached to the hand will fall from the mouth). If pain control is not achieved in 15 minutes, a second 800-microgram lozenge can be placed in the other cheek. Fentanyl can also be given intranasally with the use of a nasal atomizer.⁵² If an IV is available, then IV fentanyl or IV ketamine can be used and titrated to effect.

Ketamine at subdissociative doses is an effective pain control agent. It can be given IM, IV, IO, or intranasally via nasal atomizer or syringe with rapid onset and good efficacy. The initial dose is 50 milligrams IM or intranasally repeated every 30 minutes and titrated to effect or 20 milligrams IV/IO by slow push repeated every 20 minutes and titrated to effect.

For treatment of nausea, the TCCC Committee now recommends ondansetron, oral dissolving tablets every six hours as needed.

ANTIBIOTICS

All war wounds are dirty and contaminated. Early antibiotic use with such wounds may decrease subsequent infection.⁵³ For those able to tolerate PO administration, a single 400-milligram dose of oral moxifloxacin, found in the combat pill pack, is recommended. For casualties with hypotension or an altered level of consciousness, administer either cefotetan, 2 grams, or ertapenem, 1 gram IV.

SPECIFIC INJURIES

BURN CARE: THE RULE OF 10S

TCCC has adopted the rule of 10s for burn management, which is clinically effective and easy to implement in a prehospital environment.⁵⁴ For burns >20% total body surface area, first estimate the total body surface area burned to the nearest 10%. Then, for adults weighing 40 to 80 kg, give IV fluid as follows: 10 mL × % total body surface area burn per hour. For every 10 kg of patient weight above 80 kg, add another 100 mL of fluid per hour (resuscitation for hemorrhagic shock takes precedence over resuscitation for burn shock).

For example, for a 90-kg patient with 40% total body surface area burns, the following would be given: 40% × 10 mL = 400 mL, plus 100 mL for 10 kg above the 40 to 80 kg range, giving a total of 500 mL of IV fluid per hour. Once the patient is at a higher level of care, the fluid rate can be adjusted based on clinical status and urinary output.

BLAST INJURIES

Injuries from explosions have historically been the leading cause of deaths in combat. This trend has continued, as we see approximately 50% of combat deaths and 77% of all injuries in the global war on terror caused by explosions. There is the tendency to rely on common clinical indicators to triage blast casualties. Tympanic membrane perforation and hypopharyngeal petechiae are common findings in blast casualties; however, no correlation has yet been shown between these findings and level of injury. There are many factors that contribute to a pattern of injury, such as body orientation relative to the blast and confined versus open space, so be wary of relying on a particular clinical finding to triage casualties.⁵⁵ If anything, the most reliable sign may be respiratory distress immediately after the blast. Casualties with clinically significant lung injury typically manifest as respiratory failure within minutes of the blast.^55,56 See chapter 7 for detailed discussion.

CERVICAL SPINE INJURY

As discussed earlier, the vast majority of penetrating injuries in the combat setting do not require cervical spine immobilization, unless there is direct injury to the neck with associated neurologic deficit.⁵⁷ In fact, cervical spine immobilization (particularly with a cervical collar) will impede the ability to manage the more immediate concerns of a penetrating neck injury. Therefore, cervical spine immobilization for penetrating injury in a combat casualty is not recommended. Blunt head trauma should be treated with cervical spine immobilization, situation permitting, as practiced in the civilian sector.⁵⁸

ABDOMINAL TRAUMA

Although body armor does provide some protection to the upper abdomen, the lower abdomen is still relatively vulnerable. There is a groin attachment for the issued body armor that provides some protection to the lower abdomen, but it is not composed of a rigid Kevlar plate that is used to protect the chest and back; rather, this is a flexible Kevlar material that allows for movement at the hips, while providing some level of protection to the lower abdomen and groin region. Use of this additional piece of equipment has become more prevalent among our combat troops.

With a significant large-vessel (aorta, inferior vena cava, iliac vessels), liver, or splenic injury, there is not much a combat physician can do to save a casualty. In this situation, stabilize the casualty as best as possible, start an IV, administer antibiotics, and transport to a higher level of care with surgical capability immediately. For management of difficult-to-control, noncompressible massive hemorrhage, see the TCCC section on massive hemorrhage control.

If there is a bowel evisceration, replacing the contents will minimize insensible fluid and heat loss and allow for easier casualty movement. First remove any significant particulate matter or dirt; then attempt to replace the bowel contents intra-abdominally (this might not be possible if there is significant bowel edema and/or a small abdominal defect); cover exposed bowel and abdominal defect with a moist dressing; cover with plastic wrap or other fluid-impervious dressing to minimize insensible fluid loss; start an IV and administer IV fluids as needed; and administer IV antibiotics in preparation for evacuation.

PELVIC TRAUMA

The standard torso body armor does not provide any protection to the pelvis. A groin attachment protects the genital region and does provide some protection for the perineum, but the inguinal regions, containing large neurovascular bundles, are left largely unprotected. As such, the femoral vessels are vulnerable to penetrating injury, often resulting in life-threatening hemorrhage.

A tourniquet or pressure dressing to a proximal femoral artery or vein injury may be ineffective. For this type of injury, use of a hemostatic agent is imperative. Direct pressure should be applied to gain immediate control of the bleeding. Vessel clamping should only be attempted if an effective tourniquet or pressure dressing cannot be applied, a hemostatic dressing is not available, there is no device to control junctional hemorrhage, and there is no ability for immediate evacuation.

Pelvic fractures can result in significant hemorrhage that is difficult to control. Determination of a pelvic fracture, if not obvious, should be done from symptoms of pain and a clinical suspicion. The practice of "springing" or doing a "pelvic rock" is no longer recommended because this technique is likely more harmful than beneficial.⁵⁹ Past recommendations of improvised pelvic splinting with a sheet to produce needed compression for hemorrhage control can be used (if no other more effective options are available), but such splinting is inferior to more recent commercially manufactured pelvic splints and binders.^48,59

EXTREMITY AMPUTATION

About 7% of wounded soldiers in Operation Iraqi Freedom and Operation Enduring Freedom had a major extremity amputation, and 50% of soldiers killed in action or who died of wounds had major amputations.⁶⁰ Field treatment of an amputation is focused primarily on hemorrhage control and preserving as much tissue as possible. Often the vessels of the limb have retracted from the initial force of the amputation, making it particularly difficult to identify and control hemorrhage. It may appear that hemostasis has been achieved with little effort; however, effective hemorrhage control may be necessary in the form of a hemostatic agent, pressure dressing, or tourniquet because delayed bleeding often occurs as the damaged vessels relax and dilate shortly after the patient appears stable. Constant reevaluation of the patient is essential. A partial amputation where the limb is still attached by substantial tissue or bone should be treated the same as an open fracture with hemorrhage control, wound debridement and irrigation, antibiotic administration, and splinting in an attempt to salvage the limb.

MASS CASUALTY TRIAGE

Mass casualty or MASCAL events are generally defined as situations in which the number and needs of the casualties exceed available resources (personnel and supplies). Three casualties might represent a MASCAL for one inexperienced physician, whereas 30 casualties might not represent a MASCAL for five well-prepared physicians.

Triage is a critical aspect of managing a MASCAL (Table 302-4 provides one example of a simple triage algorithm). Another very effective method for handling a large number of casualties is the SALT mass casualty triage methodology (Figure 302-2). SALT stands for sort, assess, lifesaving interventions, and treatment/transport, which are the key activities that must be accomplished during the triage process.

THREE-TIER PRIORITIZATION

SALT begins with a global sorting of casualties, prioritizing them into three tiers for individual assessment. The triage physician directs casualties to walk to a designated area "if they need help." Those who follow the command to walk are the last priority for individual assessment, because they demonstrate an intact airway, breathing, circulation, and mental status and are therefore the least likely to have a life-threatening condition. The remaining casualties should then be asked to wave or be observed for purposeful movement. Those who remain still and do not move, as well as those with obvious life-threatening injuries, such as massive external hemorrhage, are assessed first. Those who wave are individually assessed next, followed by the ones who previously walked to a designated area. Although this initial sorting is not perfect, it is an attempt to organize numerous casualties.

INDIVIDUAL CASUALTY ASSESSMENT

The second step of SALT is to perform individual assessments and apply lifesaving interventions, such as controlling massive external hemorrhage or opening an airway. Lifesaving interventions must meet all of the following criteria: can be provided quickly; can greatly improve a casualty's likelihood of survival; does not require the physician to stay with the casualty; are within the physician's scope of practice; and require only immediately available equipment. After appropriate interventions are performed, casualties are prioritized for treatment and assigned to one of the following triage categories: immediate, delayed, minimal, and expectant (includes the dead for the purpose of military triage), known in the military by the acronym DIME.

Colored triage tags or chemical light markers can mark casualties based on triage category. Colored triage tags typically are red for immediate, yellow for delayed, green for minimal, and black for expectant or deceased. If chemical light sticks are employed, red is typically used for immediate, green/yellow for delayed, and blue for expectant. Avoid using green and yellow chemical lights for different triage categories to mirror the markings on the triage tags, because it may be difficult to distinguish the two colors during night operations.

The field triage score is another easy, rapidly applicable method to identify casualties who are more seriously injured and expected to have a higher mortality. The field triage score is based on two variables: character of the radial pulse and the motor component of the Glasgow coma scale (GCS-M), namely the ability to follow commands. A weak or absent radial pulse, which correlates with a systolic blood pressure of ≤90 to 100 mm Hg, is assigned a score of 0, whereas normal pulse character (systolic blood pressure >90 to 100 mm Hg) is assigned a score of 1. Similarly, an abnormal GCS-M (<6) is assigned a score of 0, whereas the ability to follow simple commands (GCS-M of 6) receives a score of 1. A casualty can therefore receive an aggregate field triage score of 2, 1, or 0. A retrospective review of 4988 casualties in Iraq and Afghanistan from 2002 to 2008 demonstrated that those with a field triage score of 2 had a mortality of only 0.1% (5 of 4366), whereas those with a field triage score of 1 and 0 had a mortality of 10.8% (33 of 540) and 41.4% (34 of 82), respectively.⁶¹

Triage categories are not the same as evacuation categories. Triage identifies the severity of a casualty's injuries and determines a treatment priority based on the likelihood of survival, whereas evacuation is based on the urgency of transport to definitive care and the likelihood of deterioration over time. Triage is an ongoing, dynamic process, and triage categories may change if an intervention stabilizes a casualty or if a casualty deteriorates clinically. For example, a delayed casualty with second-degree burns over 30% of his body may become immediate if unrecognized inhalational injury leads to airway swelling and compromise.

CPR

Battlefield resuscitation of victims of blast or penetrating trauma who have no pulse, respiratory effort, or other signs of life will not be successful and should not be attempted because CPR on combat casualties has failed to show any benefit.^62,63 Therefore, CPR on the battlefield is not currently recommended. Even in the civilian setting, very few trauma arrest patients survive when prehospital CPR is performed.^64,65 In a tactical situation, CPR should only be considered as a last effort if the situation permits and appropriate resources are available, and in the case of nontraumatic disorders such as hypothermia, near-drowning, and electrocution. Casualties with torso trauma or polytrauma, who are pulseless and apneic, should receive bilateral needle decompression of the chest to ensure they do not have a tension pneumothorax prior to discontinuation of care. CPR may be initiated during evacuation for casualties that do not have obviously fatal injuries and will be arriving at a facility with surgical capability within a short period of time. CPR should not be done at the expense of mission compromise or denying lifesaving care to other casualties.⁶⁶