INTRODUCTION to MILITARY TRAUMA

1. INTRODUCTIONtoMILITARY TRAUMA

2. 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.

4. Military Surgery 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. Trauma Surgery Military Surgery

5. Resources Patients

6. 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

7. 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

8. 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

9. Echelons of Health Care in ANA Medical System ECHELON IV ECHELON III ECHELON II ECHELON V U. S. Army ANA ECHELON I Self/Buddy Aid Self/Buddy Aid ECHELON I Combat Lifesaver Combat Lifesaver Combat Medic Combat Medic ECHELON I Battalion Aid Station / Medical Platoon / Medical Company Battalion Aid Station / Medical Platoon / Medical Company Garrison Clinics Comprehensive Clinics Other Clinics Combat Support Hospital Garrison Clinics Comprehensive Clinics Regional Hospitals FSMC ASMB FST Medical Company - CSS BN Medical Company - Corps Spt BN Other Clinics Field Hospital General Hospital NMH Annex Hospital Comprehensive Clinics Military Hospitals Veterans Hospitals Civilian Hospitals Government Hospitals Foreign Hospitals

10. 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

11. Civilian trauma centers • Few patients with unlimited resources • Military mass casualty • Limited resources for potentially unlimited patient numbers Resources Patients

12. Triage Principles • 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

14. 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

15. “DIME Categories • Delayed • Immediate • Minor • Expectant

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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.”

22. Triage Pearls • 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

23. 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

24. Types of Wounds and Injuries • Missiles • Explosive weapons • Thermal weapons • Biological or chemical weapons

25. WW II penetrating 86% blast 3% blunt 4% thermal 1% unkn/misc 7% Vietnam penetrating 96% blunt ---- blast ---- thermal ---- unkn/misc 4% Wounding Mechanism in Combat Casualties

26. Distribution head/neck 12% chest 16% abdomen 11% extremity 61% upper 22% lower 39% Fatalities head/neck 47% chest 24% abdomen 9.4% extremity 2.6% multiple 6% Distribution and Fatality of Wounds

27. 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 effective Most combat actions < 200 meters Most infantry not great marksman • Smaller, lighter ammo developed Less recoil, better aim Each soldier can can carry more rounds

28. Missiles (cont) • 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”

29. 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

30. 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

31. 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

33. Fragmentation/ Expansion • Some missiles are designed to fragment or expand Dum-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

34. 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

35. 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

36. Explosive Weapons Multiple mechanisms of injury • fragments • blast • thermal • possibly NBC

37. 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)

39. 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

40. Explosive Weapons • Other wounding mechanisms to be covered in following lectures Blast Thermal Chemical/Biological • Nuclear should not be a surgical problem except in contamination or triage Radiation exposure with convulsions/vomiting in the first 24 hours are expectant

41. 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

42. 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

43. 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

44. Initial Care

45. Initial Care (cont) • Surviving casualties that arrive to surgeons fit two broad categories immediate: 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.

46. 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

47. 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.)

49. 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

50. 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