INTRODUCTIONto

MILITARY TRAUMA

OBJECTIVES

• Compare basic war surgery principles versus peacetime surgical principles.

• Describe the Echelons of Care System and contrast the older system to that of today.

• Describe triage principles as they apply in the military system.

• Differentiate types of wounds, mechanism of wounding, and treatment principles.

•Identify the general principles of initial care.

Military Surgery

• Military surgery is emergency surgery performed on a mass production basis in an austere and resource-limited environment.

• Providers themselves are in jeopardy for injury.

Surgery

Military Surgery

Trauma Surgery

Res

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Patients

• CONSERVATION OF FIGHTING STRENGTH is the primary goal of medical therapy

• Military today must respond to crises and situations that are more sudden, active, and distant

• In a sudden conflict, medical channels that return soldiers to duty may be the only functional personnel replacement

• The medical system can not merely become evacuation conduit from combat zone-- but this is changing in today’s conflicts

Surgeon’s Role

• Will be intimately involved in triage of casualties• May be involved with resuscitative and/or

reconstructive surgery• May be deployed to locations from far-forward to

inside Kabul• Role is continually evolving toward a more

forward presence

Echelons of Care

• Organized to distribute resources to various levels of location and function

• Not a rigid prescription, especially in today’s war or operations

• New scheme with “smaller footprint”• first responder• forward surgery “en route care”• theater hospital

Echelons of Health Care in ANA Medical System

ANAU. S. Army

General HospitalField Hospital NMH Annex Hospital

Veterans Hospitals

Military Hospitals Foreign HospitalsCivilian Hospitals Government Hospitals

FSMC ASMB FST Medical Company - CSS BN Medical Company - Corps Spt BN

Garrison Clinics Comprehensive Clinics

Combat Support Hospital Regional Hospitals Comprehensive Clinics

Battalion Aid Station / Medical Platoon / Medical Company

Combat Medic

Combat Lifesaver

Self/Buddy Aid

Combat Medic

Combat Lifesaver

Self/Buddy Aid

Garrison Clinics Comprehensive Clinics

Battalion Aid Station / Medical Platoon / Medical Company

Other Clinics

Other Clinics

Triage

• First described in Napoleon's Army, from the French “Trier” to sort

• Based on principle of doing the greatest good for the greatest number with the time and resources available

• Civilian trauma centers and military triage situations differ

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Patients

Civilian trauma centers

Few patients with unlimited resources

Military mass casualty

Limited resources for potentially unlimited patient numbers

• In mass casualty situation, triage is paramount in optimizing available resources to benefit most victims

• The Surgeon should be intimately involved in the triage process

• Triage is dynamic and evolves as the situation and resource availability change

Triage Principles

The Four Standard U.S. Military Triage Categories

• Immediate• Urgent• Delayed• Expectant

These relate to the speed and priority for transporting the patients from the scene to a medical care facility

“DIME Categories

• Delayed

• Immediate

• Minor

• Expectant

Triage Category “Immediate”

• You determine the patient has a threat to life or limb

• A slightly injured patient is immediate if he can return to duty with immediate, simple, and short time-frame management

• Usually requires initial emergency treatment prior to transfer

• If transport is not truly immediate, should be within one hour

Triage Category “Urgent”

• The patient is at risk if treatment or transportation is unreasonably delayed

• Generally, transport to a medical facility in less than 2 hours

Triage Category “Delayed”

• No risk to life or poor consequences expected if more definitive care is not rendered quickly

• Ideally transported in less than 6 hours, but 24-hour wait may be required

Triage Category “Expectant”

• Regardless of the level of care rendered, the patient is likely to expire (die)

• Is a difficult and stressful decision to make for unit personnel

• Comfort care is still indicated

Examples of each Triage Category

• Immediate - Airway injuries, unconscious, shock, respiratory compromise, limb arterial injuries, trunk gunshot wounds, any major bleeding, major truncal burns

• Urgent - Closed proximal limb fractures, extremity burns

• Delayed - Distal extremity injuries, simple lacerations

• Expectant - Open brain injuries, major dismemberment

The Difficult Decision

“To categorize a soldier to the expectant category requires a resolve that comes only with prior experience in futile surgery that ties up operating rooms and personnel while more salvageable casualties wait, deteriorate, or even die.”

• The most severely injured will be the first to be evacuated and to arrive so guard against overcommiting resources on those first victims

• Communication with the field is important to develop an overall perspective of the total number and types of casualties expected.

• Keep the triage area informed of the OR situation.• Stable (delayed) patients triaged as Immediate• Triage changes as situations change

Triage Pearls

Limited Resources

• Surgeon fatigue factor

• OR, anesthesia, blood product and ventilator availability

• Post-op holding capacity

• Evacuation capability and time to next level of care

• Surgical instruments and supplies

Types of Wounds and Injuries

• Missiles

• Explosive weapons

• Thermal weapons

• Biological or chemical weapons

Wounding Mechanism in Combat Casualties

WW II• penetrating 86%

• blast 3%

• blunt 4%

• thermal1%

• unkn/misc 7%

Vietnam• penetrating 96%

• blunt ----

• blast ----

• thermal----

• unkn/misc 4%

Distribution and Fatality of Wounds

Distributionhead/neck 12%chest 16%abdomen 11%extremity 61%

upper 22%lower 39%

Fatalitieshead/neck 47%chest 24%abdomen 9.4%extremity 2.6%multiple 6%

Missiles

• In the past, differentiation made between HI and LOW velocity weapons but now felt not to be totally different entities.

• Change to higher velocity weapons a result of change to smaller and lighter automatic weapons

• Automatic weapons more effectiveMost combat actions < 200 meters

Most infantry not great marksman

• Smaller, lighter ammo developedLess recoil, better aim

Each soldier can can carry more rounds

• To maintain wounding power, higher bullet velocities were necessary

• Higher velocities developed to increase FIREPOWER, not wounding power (same)

• Always potential for higher energy transfer with higher velocity, but this is not always the case

• Surgeon should always be concerned with the individual wound, rather than the “worst case scenario”

Missiles (cont)

Mechanism of Wounding

• Missile or fragment destroys tissue by passing through and crushing it (PERMANENT CAVITY)

• Cross-sectional area of the permanent cavity is comparable to the presenting area of the missile and is the same for ALL tissue types

• Not the only mechanism of wounding

• After passage of the projectile, the walls of the permanent cavity are stretched radially outward creating a TEMPORARY CAVITY

• Damage in the temporary cavity results from stretching of the tissue

• Tissue elasticity determines the damage the tissue sustains

Mechanism of Wounding

• Same degree of stretch in one tissue (muscle) that may cause little injury can result devastating injury in another (liver, brain)

• Zone of temporary cavitation is analogous to an area of blunt trauma around the projectile’s tract

• Summation of the two types of tissue disruption gives the wounding potential of the missile

Mechanism of Wounding

• Some missiles are designed to fragment or expandDum-dums, Hollow-points, Non-jacketed, Some fragments despite copper jacket (M-16)

• Fragments cause multiple tracts of permanent and temporary cavities

• Expansion makes the permanent cavity wider

Fragmentation/ Expansion

Yaw

• Yaw is the deviation in the longitudinal axis of the bullet from its line of flight (tumbling)

• Yaw is usually 180 degrees and can be caused by striking foliage or tissue

• It increases the area of permanent and temporary cavitation

• Important in the injuries caused by AK-47, AK-74

Shotgun Injuries

Shotgun shells have a big powder charge with a large mass of lead balls

• Destructive potential depends on range

• At close range, it can cause a large wound with severe disruption of anatomy by direct crush alone

• Long range (>25m) cause usually only skin wounds

• Wadding is a projectile too

Explosive Weapons

Multiple mechanisms of injury• fragments• blast• thermal• possibly NBC

Fragmentation

Act as missiles• Blunt, irregular shape

lose velocity rapidly/ less tissue penetration

• Made of steel usually, less dense• Initial velocity very great, but drops off rapidly

> 5900 m/s (initial)------< 1900 m/s (survivors)

• Body armor provides much better protection against fragments than bullets

• Tissue damage is from the crush rather than stretch• Land mine injuries are fragment injuries with

extensive anatomic disruption• Primary thing to remember of these and all missile

injuries is to treat the INDIVIDUAL WOUND rather than the weapon

Explosive Weapons

• Other wounding mechanisms to be covered in following lecturesBlast

Thermal

Chemical/Biological

• Nuclear should not be a surgical problem except in contamination or triageRadiation exposure with convulsions/vomiting in

the first 24 hours are expectant

General Principles of CareInitial Care

Advanced Trauma Life Support

• Guide to recognition of many immediately life-threatening injuries and initial care

• Developed for civilian trauma, not military

• Targeted for primary care provider, not trauma surgeons

Trauma vs. Military Surgery

• Civilian trauma predominantly blunt while military is penetrating

• Most penetrating trauma in the military is high velocity

• Military trauma care is performed in an austere, mass casualty setting

Initial Care

“Trimodal” distribution of death in trauma• At scene--golden hour--late sepsis/MOF

Most military fatalities due to penetrating injury and rapid death from exsanguination• 70% die in the first 5 minutes, 80-90% in first

hour• Thus, most wounded with fatal injuries die prior

to transport or arrival to care

Initial Care

Initial Care (cont)

• Surviving casualties that arrive to surgeons fit two broad categoriesimmediate: needing immediate intervention to

control hemorrhage

delayed, minimal, expectant

• The closer (sooner) to the front line resuscitative surgery is performed the better the patient outcome.

Initial Care (cont)

• ATLS provides a guide to principles of resuscitation and diagnosis

• A surgeon’s role in military setting goes beyond ATLS and involves complex and specific knowledge, skills, and judgement

• Lectures to follow will give ground-work for this level of care by organ system

General Principles of Care of Battlefield Wounds

• Battlefield are very contaminated places

• Frequently time lag between injury and treatment

• Combat wounds have extensive tissue destruction

• Some victims are immune compromised(prisoners, non-combatants, etc.)

Early, Adequate Surgery is the Answer

• Most important steps are stopping hemorrhage and avoiding infection and sepsis

• Hemorrhage control techniques in following lectures

• Wounds debrided of nonviable, contaminated tissue with good blood supply are best able to resist infection

Debridement

4 “C”s of wound debridement: color, consistency, contractility, and circulation• Pulsatile irrigation is useful adjunct• Debridement should be thorough and leave only

viable tissue• A second-look at 24-48 hours can be done if

questionably viable tissue remains• Antiseptics are good for prepping wound• Drain and delay primary closure or secondarily

close all war wounds

Antibiotics

• Use broad spectrum antibiotics from available drugs in unit stock

• Be sure to have clostridial and strep coverage

• Antibiotics do not replace adequate and prompt debridement

• Assure tetanus prophylaxis and administer toxoid/ immunoglobulin as indicated

Wound Problems

• Delay in surgery/ inadequate debridement• Vascular injury with regional tissue ischemia• Hematoma due to inadequate hemostasis• Retained foreign body• Inadequate drainage• Primary closure war wounds• Missed hollow viscus injury• Contaminated by resistant organisms

Other Particulars to War Injuries

Become familiar with them through this course, reading, and training• Time lag from wounding to treatment• Time without close care during transfer• Interruption in the continuity or care by same

MD or team• Particulars of aeromedical transport

Other Particulars (cont)

• Battlefield security• protection of hospital and personnel from enemy or

friendly action

• breakdown of lines of evacuation and supply

• air superiority and impact on you situation

• checking of injured for weapons

• Possible bio-chem contamination

• Psychological and physical stresses of deployment, combat, and mass casualties

Other Particulars (cont)

Combined wounding mechanisms• blunt• penetrating• thermal• blast• NBC• disease/malnutrition• psychological

Unexploded Ordnance