The war on terrorism has been marked by continuous conflicts in Iraq, Afghanistan, and other theaters for the past 15 years. Distinct from previous conflicts, recent wars have seen a far greater percentage of injuries occur as a result of blast mechanisms; these injuries lead to the greatest utilization of resources and long-term patient disability.1,2 One hallmark injury of these conflicts has been devastating but survivable extremity trauma. Patients with severe, previously fatal extremity injuries are now surviving as a result of advances made on the modern battlefield, including the use of field tourniquets, rapid air evacuation to forward surgical units, and early and aggressive resuscitation strategies, all of which occur in far forward austere facilities. These military advances have been extrapolated to mass casualty and other disaster management scenarios outside of combat theaters of operation, with no area more pronounced in its effect on survival than that of patient resuscitation and the treatment of hemorrhagic shock.3–6
Patients with orthopaedic trauma sustained in combat frequently present in hemorrhagic shock as a result of traumatic amputations, open long bone fractures with massive soft tissue injuries, and pelvic ring disruptions. As part of forward surgical units, military orthopaedic surgeons are engaged not just in the management of orthopaedic injuries but rather in the total care of the traumatized patient. Combat orthopaedic surgeons must therefore be comfortable with patient resuscitation strategies, close coordination with general surgeons, and the temporizing measures necessary to manage extremity and pelvic trauma before evacuation, directly contributing to survival and long-term functional outcomes.
DEFINITION OF SHOCK AND PRINCIPLES OF RESUSCITATION
Definition of Shock
Shock is defined as failure of the cardiovascular system to provide adequate perfusion and oxygenation to organs and tissue.7 These effects, while initially reversible, rapidly become irreversible and often fatal if the underlying etiology is not treated promptly. Although hemorrhage is by far the most common etiology managed in combat, other forms of shock can occur to include obstructive shock due to tension pneumothorax or cardiac tamponade or neurogenic shock, which must be ruled out during the primary survey.8–10
Principles of Resuscitation
The widespread use of body armor in combat has left penetrating extremity trauma as the most common source of bleeding in the patient presenting with shock. Identifying and stopping sources of continued bleeding is the first and most important step in the primary survey, occurring before both airway and breathing assessment.11,12 This hypervigilance to seek and immediately stop ongoing blood loss stems from historical war data demonstrating that 50% of combat deaths are from hemorrhage and from more recent data demonstrating that 91% of potentially survivable prehospital deaths in Iraq and Afghanistan over a 10-year period were due to hemorrhage.10,11
During the primary survey, if a source of significant hemorrhage is identified, it is immediately addressed while continuing the patient assessment. The Tactical Combat Casualty Care (TCCC) guidelines recommend the use of extremity tourniquets early in the prehospital environment for bleeding wounds not controlled by pressure dressings.13–15 This has led to a significant reduction in combat deaths related to exsanguination from extremity wounds and has resulted in presentation of more casualties to surgical facilities with tourniquets placed immediately at the time of injury by combat medics, battle buddies, and other soldiers. Tourniquets should remain in place, especially while still in shock, until the extremity can be assessed in the operating room and surgical control obtained. Bleeding not controlled with a tourniquet should be assessed for effectiveness because tourniquet “tightness” must increase if thigh or arm swelling occurs.16
The use of field tourniquets is simple but requires a working knowledge of how they function to avoid common pitfalls during application. When not adequately tightened, a paradoxical increase in bleeding will occur because arterial inflow is not fully occluded but venous outflow is blocked.17 If one field tourniquet is not effective, placement of a second immediately proximal may be necessary for hemorrhage control. Pneumatic tourniquets should be applied as secondary tourniquets when available.18
Bleeding wounds of the trunk, axilla, and groin pose a significant challenge, especially in the prehospital setting because these areas are not amenable to control using tourniquets. TCCC guidelines recommend treatment for these areas with topical hemostatic dressings and direct pressure; Combat Gauze is the first line choice.19 Junctional tourniquets such as the Combat Ready Clamp have been shown to be effective in case series and studies in healthy volunteers and are currently approved by Food and Drug Administration. They are recommended by the TCCC for use in the prehospital environment when available because direct pressure during patient movement on the battlefield is difficult.20,21 At a surgical facility, these wounds should be controlled with direct pressure or balloon tamponade. Foley catheters are universally available, easy to use, and effective as balloon tamponade devices until the patient can be rapidly transported to the operating room to obtain surgical control. They can be used for small bleeding wounds of the axilla, torso, and groin that are difficult to control; the balloon (ideally 30 cm3) is inflated and secured at skin level. In mass casualty scenarios, patients with effective limb tourniquets in place may be triaged to follow patients with uncontrolled hemorrhage to the operating room but should be prioritized accordingly because the risk of progressive and permanent neuromuscular injury increases with ischemia time and becomes significant and potentially irreversible at 4+ hours.16
Although extremity and truncal open wounds are obvious as sources of bleeding, adjuncts are often necessary in the forward environment to diagnose more occult sources of bleeding from the chest and abdomen. Forward surgical units now have routine access to plain radiography and/or ultrasound, allowing for focused assessment with sonography in trauma (FAST) examination and a chest x-ray during the secondary survey. FAST is effective at diagnosing both abdominal hemorrhage and pericardial tamponade, but has its limitations, particularly assessment of the retroperitoneal space. Despite early enthusiasm for FAST, recent studies have demonstrated sensitivities as low as 22% in hemodynamically stable and 28% in hemodynamically unstable patients.22 Diagnostic peritoneal aspiration remains an effective tool to assess for intraabdominal hemorrhage when suspicion is high and the FAST examination is negative because computed tomography is unavailable in forward surgical units. Aspiration of any amount of blood is considered a positive test; therefore, diagnostic peritoneal aspiration is simpler than lavage, with a sensitivity of 89% and specificity of 100% in detecting hemorrhage significant enough to cause hypotension.23,24
Early recognition of shock should be quickly followed by aggressive use of fluids, blood products, and thrombostatic medications for resuscitation, particularly in those meeting criteria for massive transfusion (MT). Current recommendations, based on military studies from the past 15 years and confirmed in the civilian trauma literature, call for an effective transfusion ratio of packed red blood cells, fresh frozen plasma (FFP), and platelets of as close to 1:1:1 as possible. Surgeons should administer blood products as soon as possible; crystalloids need not be given first and have been associated with increased rates of Acute Respiratory Distress Syndrome, abdominal compartment syndrome, multisystem organ failure, and death. Tranexamic acid is also effective as a first-line agent for control of hemorrhage and should be given as soon as shock is diagnosed because its benefit is most pronounced when given within 1 hour of injury and is most effective in those requiring MT (>10 units of blood products in 24-hour period).25,26 Tranexamic acid should be dosed at 1000 mg over 10 minutes initially, with a repeat dose of 1000 mg over 8 hours.
MT scenarios can quickly exhaust a forward unit's entire supply of blood products, and in these situations, MT protocols should be initiated, which may include whole blood transfusion as part of a unit-based blood drive. Fresh whole blood is warm, provides a higher hematocrit, platelet count, coagulation factor activity, and fibrinogen than 1:1:1 component therapy—with 10 U of cryoprecipitate.27 The main risk of whole blood use is a fatal acute hemolytic reaction; recommendations for whole blood use in the deployed environment include type-specific blood.28 Finally, recombinant activated factor VII (factor VIIa), whose use was popular early in the conflicts, is currently not a part of any military protocols or algorithms for dealing with MT scenarios or ongoing hemorrhage due to studies being mixed with regard to survival benefit and risk of thrombotic events.29,30
Two recent emerging adjuncts to control massive hemorrhage in the combat environment are the administration of freeze-dried plasma (FDP) and the technique of retrograde endovascular balloon occlusion of the aorta.31–35 Retrograde endovascular balloon occlusion of the aorta is an emerging technology to provide intraluminal aortic control of noncompressible truncal hemorrhage. Although first described in the Korean War, renewed interest has emerged in complex war trauma. The technique involves placing an endovascular balloon from the common femoral artery to the level of the descending aorta, occluding distal flow. It is considered for use as an alternative to resuscitative thoracotomy and external occlusion of the aorta in cases of traumatic arrest or profound shock with systolic blood pressure <90 mm Hg. It may have the most mortality benefit when used early in patients at significant risk of profound hemorrhagic shock who have not yet arrested, increasing systolic blood pressure by a mean of 53 mm Hg and maintaining perfusion to the heart and central nervous system during resuscitation before formal surgery to address the bleeding etiology.33
FDP represents a life-saving product being used on the battlefield and in select civilian trauma centers. FDP has similar efficacy to FFP in treating coagulopathy but has an extended 2 years shelf life, can be stored at room temperature, can be made ABO-universal, and reconstitutes with ease.32,33 Despite concerns regarding disease transmission due to blood pooling, a recent study using FDP at a deployed French field hospital showed similar efficacy to standard FFP with no adverse events.36
DAMAGE CONTROL ORTHOPAEDICS
Combat-injured patients with extremity fractures, traumatic amputations, and/or pelvic ring injuries benefit from temporizing treatment approaches downrange. Timing of early antibiotic coverage and surgical control of extremity hemorrhage take precedence over prompt debridement and spanning external fixation, which can be performed if time and patient status allow but which should never delay evacuation to a higher level of care for life-threatening chest, abdominal, or head injuries. Current recommendations for combat-related open fractures include gram-positive coverage with a cephalosporin and recommend against use of aminoglycosides for gram-negative coverage.37 Although numerous indices (lactate, base deficit, IL-6) are available to guide decision making and categorize patients regarding early total care versus damage control surgery in a civilian setting, they are of limited value in an austere theater of operations; definitive surgery is best performed after evacuation out of theater to a fixed military hospital. External fixators are effectively applied to manage open and closed lower extremity long bone fractures; they can be applied quickly and safely, without the use of fluoroscopy, and are readily available in both mobile and fixed forward surgical units.38 Traumatic amputations, although benefiting from early debridement and hemorrhage control, should never be shortened downrange but maintained at maximal length that bone and soft tissues allow. Even if an adjacent proximal fracture is present, only devitalized and highly contaminated tissue is excised to allow for length preservation with proven methods to stabilize fractures in the residual limb once evacuated.39
Addressing Vascular Injuries
Penetrating extremity trauma frequently is associated with vascular injury, either isolated or in the setting of associated fracture. Because forward surgical units do not have a vascular surgeon available, orthopaedic surgeons must be comfortable with temporary shunting of dysvascular limbs before evacuation to a higher level of care, where definitive vascular reconstruction can occur. The technique for placement of a vascular shunt after obtaining proximal and distal control involves choosing a shunt with a diameter that closely matches the native vessel, thrombectomy of the artery to obtain brisk back-bleeding, instillation of heparinized saline proximally and distally, followed by placement of the shunt into the native vessel to a distance of 1.5–2 cm.40,41 Although venous extremity injuries can be ligated in damage control situations, venous shunts, along with the liberal use of fasciotomies, reduce the risk of secondary thrombosis of the arterial shunt and the development of acute compartment syndrome (ACS).40 Shunted limbs associated with fracture should always have a spanning external fixator placed to stabilize the limb and prevent shunt thrombosis or dislodgement during evacuation.
Acute Compartment Syndrome
Orthopaedic surgeons must also be aware of the high incidence of ACS seen after combat-related extremity trauma, even in the absence of a tibia fracture. If clinical suspicion for ACS exists or is supported by injury mechanism in the obtunded or intubated patient, prophylactic fasciotomies should be performed emergently before evacuation.42 Because the consequences of missed compartment syndrome far outweigh the risks of an unnecessary fasciotomy and the potential for lengthy evacuations, combat surgeons are encouraged to liberally perform fasciotomy in the forward environment. Despite recent reports indicating that 4-compartment fasciotomy is safely performed through a single lateral incision, it is recommended for austere deployed environments to continue the use of 2 incisions to avoid the risk of an incomplete deep posterior compartment release.43,44
Acute Management of Pelvic Ring Injuries
Early identification of unstable pelvic ring injuries remains a critical aspect of the primary survey downrange. Once diagnosed, application of a well-positioned binder or sheet over the greater trochanters serves as an immediate maneuver capable of reducing the pelvic volume and stabilizing the pelvis, which aids in clot formation.45,46 Sheets afford the benefit of widespread availability, can be cut for vascular access, and can be left in place without impeding access for emergent laparotomy, preperitoneal pelvic packing, or conversion to external fixation. Surgeons in far forward environments should be prepared to perform pelvic packing when hemodynamic instability and shock persist despite mechanical stabilization of the pelvis and aggressive attempts at resuscitation; invasive angiography is unavailable in austere environments and far forward surgical units. Preperitoneal packing can be performed quickly through a small suprapubic incision. After external fixator stabilization of the pelvis, laparotomy sponges are packed into the traumatic cavity of the true pelvis. These create a tamponade effect adequate to control bleeding and provide for clot formation.47 When an external fixator is placed in the deployed setting, the iliac crest is used with at least 2 pins placed per side; intraoperative fluoroscopy is not available to guide pin placement in other areas of the hemipelvis.
Extrapolating Military Experience to Civilian Applications
The advances described above may have had their genesis and greatest application in the combat setting, but these techniques have been adopted where appropriate in the civilian sphere and reflect a beneficial bidirectional evolution in trauma care. The earlier use of blood products with a 1:1:1 ratio has become standard in many civilian centers, and tourniquets are now routinely used by civilian emergency providers as well; effective tourniquet application was credited with saving lives during the Boston Marathon bombing.48–51 This serves as a reminder to civilian providers that complex extremity war-type wounds and mass casualty situations may occur in their communities, as events such as the San Bernadino shootings and the multi-centric Paris attack with bombs and high-velocity assault weapons have shown.52 In addition to the time honored military practice of triage, the more recent principles of resuscitation, hemorrhage control, and damage control orthopaedics are valuable lessons for any orthopaedic surgeon-military or civilian (Table 1).
Advances in the care of polytraumatized patients with extremity injuries continue to occur as a result of modern challenges faced on the battlefield. Hemorrhage control as a result of proven and emerging resuscitative strategies and surgical techniques has led to a greater likelihood of survival after devastating bodily injury than at any prior point in our military's history. Future research will need to identify which of these strategies are most effective on the modern battlefield, one where surgical units must be lighter, smaller, and more mobile to support the changing scope of military combat operations. These lessons will continue to be applicable to civilian settings, particularly when addressing complex open injuries, natural disasters, and mass casualty events.
1. Owens BD, Kragh JF Jr, Wenkle JC, et al. Combat wounds in operation Iraqi freedom and operation enduring freedom. J Trauma. 2008;64:295–299.
2. Masini BD, Waterman SM, Wenke JC, et al. Resource utilization and disability outcome assessment of combat casualties from operation Iraqi freedom and operation enduring freedom. J Orthop Trauma. 2009;23:261–266.
3. Langan NR, Eckert M, Martin MJ. Changing patterns of in-hospital deaths following implementation of damage control resuscitation
practices in US forward military treatment facilities. JAMA Surg. 2014;149:904–912.
4. Palm K, Apodaca A, Spencer D, et al. Evaluation of military trauma system practices related to damage-control resuscitation
. J Trauma Acute Care Surg. 2012;73(6 suppl 5):S459–S464.
5. Kotwal RS, Butler FK, Montgomery HR, et al. The Tactical combat casualty care TCCC guidelines? Proposed Change 1301. J Spec Oper Med. 2013;13:82–87.
6. Eastridge BJ, Wade CE, Spott MA, et al. Utilizing a trauma systems approach to benchmark and improve combat casualty care. J Trauma. 2010;69(suppl 1):S5–S9.
7. Andersen GØ. Circulatory shock
. N Engl J Med. 2014;370:583.
8. Vadakel H, Rizzolo D. Shock
: early recognition and resuscitation
are key. JAAPA. 2013;26:21–24.
9. Eastridge BJ, Mabry RL, Seguin P, et al. Death on the battlefield (2001–2011): implications for the future of combat casualty care. J Trauma Acute Care Surg. 2012;73(6 suppl 5):S431–S437.
10. Kotwal RS, Montgomery HR, Kotwal BM, et al. Eliminating preventable death on the battlefield. Arch Surg. 2011;146:1350–1358.
11. Jenkins D, Stubbs J, Williams S, et al. Implementation and execution of civilian remote damage control resuscitation
. 2014;41(suppl 1):84–89.
12. Hooper T, Nadler R, Butler FK, et al. Implementation and execution of military forward resuscitation
programs: reply. Shock
. 2014;41(suppl 1):102–103.
13. Bennett BL, Littlejohn LF, Kheirabadi BS, et al. Management of external hemorrhage
in Tactical combat casualty care: chitosan-based hemostatic gauze dressings—TCCC guidelines-change 13-05. J Spec Oper Med. 2014;14:40–57.
14. Schauer SG, Robinson JB, Mabry RL, et al. Battlefield Analgesia: TCCC guidelines are not being followed. J Spec Oper Med. 2015;15:85–89.
15. Shackelford SA, Butler FK, Kragh JF, et al. Optimizing the use of limb tourniquets in tactical combat casualty care: TCCC guidelines change 14-02. J Spec Oper Med. 2015;15:17–31.
16. Walters TJ, Mabry RL. Issues related to the use of tourniquets on the battlefield. Mil Med. 2005;170:770–775.
17. Bulger EM, Snyder D, Schoelles K, et al. An evidence-based prehospital guideline for external hemorrhage
control: American College of Surgeons Committee on Trauma. Prehosp Emerg Care. 2014;18:163–173.
18. Kragh JF, Murphy C, Dubick MA, et al. New tourniquet device concepts for battlefield hemorrhage
control. US Army Med Dep J. 2011:38–48.
19. Deal VT, McDowell D, Benson P, et al. Tactical combat casualty care February 2010. Direct from the Battlefield: TCCC lessons learned in Iraq and Afghanistan. J Spec Oper Med. 2010;10:77–119.
20. Theodoridis CA, Kafka KE, Perez AM, et al. Evaluation and testing of junctional tourniquets by special operation forces personnel: a comparison of the combat ready clamp and the junctional emergency treatment tool. J Spec Oper Med. 2016;16:44–50.
21. Kragh JF, Johnson JE, Henkel CK, et al. Technique of axillary use of a combat ready clamp to stop junctional bleeding. Am J Emerg Med. 2013;31:1274–1276.
22. Carter JW, Falco MH, Chopko MS, et al. Do we really rely on fast for decision-making in the management of blunt abdominal trauma? Injury. 2015;46:817–821.
23. Kuncir EJ, Velmahos GC. Diagnostic peritoneal aspiration—the foster child of DPL: a prospective observational study. Int J Surg. 2007;5:167–171.
24. Cha JY, Kashuk JL, Sarin EL, et al. Diagnostic peritoneal lavage remains a valuable adjunct to modern imaging techniques. J Trauma. 2009;67:330–334; discussion 334–6.
25. Nadler R, Gendler S, Benov A, et al. Tranexamic acid at the point of injury: the Israeli combined civilian and military experience. J Trauma Acute Care Surg. 2014;77(3 suppl 2):S146–S150.
26. Morrison JJ, Dubose JJ, Rasmussen TE, et al. Military application of tranexamic acid in trauma emergency resuscitation
(MATTERs) study. Arch Surg. 2012;147:113–119.
27. Gaskin D, Kroll NA, Ochs AA, et al. Far forward Anesthesia and massive blood transfusion: two cases revealing the challenge of damage control resuscitation
in an austere environment. AANA J. 2015;83:337–343.
28. Murdock AD, Berséus O, Hervig T, et al. Whole blood: the future of traumatic hemorrhagic shock resuscitation
. 2014;41(suppl 1):62–69.
29. Bucklin MH, Acquisto NM, Nelson C. The effects of recombinant activated factor VII dose on the incidence of thromboembolic events in patients with coagulopathic bleeding. Thromb Res. 2014;133:768–771.
30. Smith JE. The use of recombinant activated factor VII (rFVIIa) in the management of patients with major haemorrhage in military hospitals over the last 5 years. Emerg Med J. 2013;30:316–319.
31. Sunde GA, Vikenes B, Strandenes G, et al. Freeze dried plasma and fresh red blood cells for civilian prehospital hemorrhagic shock resuscitation
. J Trauma Acute Care Surg. 2015;78(6 suppl 1):S26–S30.
32. Glassberg E, Nadler R, Gendler S, et al. Freeze-dried plasma at the point of injury: from concept to doctrine. Shock
33. Saito N, Matsumoto H, Yagi T, et al. Evaluation of the safety and feasibility of resuscitative endovascular balloon occlusion of the aorta. J Trauma Acute Care Surg. 2015;78:897–903.
34. Morrison JJ, Galgon RE, Jansen JO, et al. A systematic review of the use of resuscitative endovascular balloon occlusion of the aorta in the management of hemorrhagic shock
. J Trauma Acute Care Surg. 2016;80:324–334.
35. Morrison JJ, Ross JD, Rasmussen TE, et al. Resuscitative endovascular balloon occlusion of the aorta: a gap analysis of severely injured UK combat casualties. Shock
36. Martinaud C, Ausset S, Deshayes AV, et al. Use of freeze-dried plasma in French intensive care unit in Afghanistan. J Trauma. 2011;71:1761–1764.
37. Hospenthal DR, Murray CK, Andersen RC, et al. Guidelines for the prevention of infection after combat-related injuries. J Trauma. 2008;64(3 suppl):S211–S220.
38. Possley DR, Burns TC, Stinner DJ, et al. Temporary external fixation is safe in a combat environment. J Trauma. 2010;69(suppl l):S135–S139.
39. Gordon WT, O'Brien FP, Strauss EE, et al. Outcomes associated with the internal fixation of long-bone fractures proximal to traumatic amputations. J Bone Joint Surg Am. 2010;92:2312–2318.
40. Taller J, Kamdar JP, Greene JA, et al. Temporary vascular shunts as initial treatment of proximal extremity vascular injuries during combat operations: the new standard of care at Echelon II facilities? J Trauma. 2008;65:595–603.
41. Rasmussen TE, Clouse WD, Jenkins DH, et al. The use of temporary vascular shunts as a damage control
adjunct in the management of wartime vascular injury. J Trauma. 2006;61:8–12.
42. Ritenour AE, Dorlac WC, Fang R, et al. Complications after fasciotomy revision and delayed compartment release in combat patients. J Trauma. 2008;64(2 suppl):S153–S161.
43. Bible JE, McClure DJ, Mir HR. Analysis of single-incision versus dual-incision fasciotomy for tibial fractures with acute compartment syndrome. J Orthop Trauma. 2013;27:607–611.
44. Emergency War Surgery, 4th United States Revision. Chapter 23: Amputations. TX: Borden Institute. US Army medical Department center and School, Fort Sam Houston. 2013;23:341–347.
45. Mohanty K, Musso D, Powell JN, et al. Emergent management of pelvic ring injuries: an update. Can J Surg. 2005;48:49–56.
46. Grimm MR, Vrahas MS, Thomas KA. Pressure-volume characteristics of the intact and ruptures pelvic retroperitoneum. J Trauma. 1998;44:454–459.
47. Osborn PM, Smith WR, Moore EE, et al. Direct retroperitoneal pelvic packing versus pelvic angiography: a comparison of two management protocols for haemodynically unstable pelvic fractures. Injury. 2009;40:54–60.
48. Holcomb JB, del Junco DJ, Fox EE, et al. PROMMTT Study Group: the prospective, observational, multicenter, major trauma transfusion (PROMMTT) study: comparative effectiveness of a time-varying treatment with competing risks. JAMA Surg. 2013;148:127–136.
49. Kutcher ME, Kornblith LZ, Narayan R, et al. A paradigm shift in trauma resuscitation
: evaluation of evolving massive transfusion practices. JAMA Surg. 2013;148:834–840.
50. Scell R, Smith A, McSwain NE Jr, et al. A multi-institutional analysis of prehospital tourniquet use. J Trauma Acute Care Surg. 2015;79:10–14.
51. King DR, Larentzakis A, Ramly EP; Boston Trauma Collaborative. Tourniquet use at the Boston Marathon bombing: lost in translation. J Trauma Acute Care Surg. 2015;78:594–599.
52. Hirsch M, Carli P, Nizard R, et al. The medical response to multisite terrorist attacks in Paris. Lancet. 2015;386:2535–2538.