Introduction

Vascular disruption with hemorrhage remains a leading cause of death in both civilian and wartime trauma. In the civilian setting, hemorrhage is present in 15% to 25% of admissions; and studies from the wars in Afghanistan and Iraq show that the rate of vascular injury in combat is approximately 10%. Hemorrhage can be broadly considered as originating from either extremity or torso vessels, a distinction of significant clinical importance. Extremity hemorrhage is generally compressible, meaning those bleeding vessels can be amenable to immediate control with manual pressure or tourniquet application. This is in contrast to torso hemorrhage which is usually noncompressible meaning vessels that are not amenable to control with direct pressure and generally require surgical control of the hemorrhage ( Fig. 8-1 ).

The shaded area denotes the region where noncompressible torso hemorrhage is anatomically located.

(From: Blackbourne LH, Czarnik J, Mabry R, et al: Decreasing killed in action and died of wounds rates in combat wounded. J Trauma 69[1]:1–4, 2010.)

Although extremity hemorrhage is a more common injury in trauma practice, noncompressible torso hemorrhage (NCTH) carries a far greater burden of mortality. Civilian studies demonstrating that NCTH accounts for 60% to 70% of mortality following otherwise survivable injuries (i.e., no lethal head or cardiac wounds) clearly emphasizes the lethality of this injury pattern. Hemorrhage is also a significant problem in the wartime setting, accounting for up to 60% of deaths in potentially survivable-injury scenarios. Studies on those killed in action in Afghanistan and Iraq have shown that of deaths occurring in the setting of otherwise survivable injuries, 80% were a result of bleeding from disruption of vascular structures within the torso.

The distinction between compressible extremity hemorrhage and NCTH is notable as there has been a demonstrable reduction in mortality with a better understanding of the epidemiology of extremity injury and the need to rapidly control hemorrhage with tourniquets and/or topical hemostatic agents. There has been no such reduction in mortality in the setting of NCTH.

The Military and Civilian Epidemiology of Torso Hemorrhage

One of the first studies to recognize the importance of vascular disruption and uncontrolled truncal hemorrhage was by Holcomb et al, who reviewed autopsy findings of special operations forces personnel killed early in the wars in Afghanistan and Iraq. A panel of experts reviewed the records of 82 fatalities and judged them as nonsurvivable (e.g., lethal head or cardiac wounds) or potentially salvageable. This was one of the first studies to specifically use the term “noncompressible truncal hemorrhage,” although it was not specifically defined. NCTH was found to be the cause of death in 50% of patients judged to have sustained potentially survivable injuries. Kelly at al used a similar methodology to analyze 997 U.S. military deaths that occurred within two time periods: 2003-2004 and 2006. Hemorrhage was the leading cause of death in those with otherwise survivable injuries and accounted for 87% and 83% of deaths during these respective periods. Airway problems, head injury, and sepsis constituted the remaining causes of death.

Within the hemorrhage group, 50% were due to NCTH and 33% to extremity hemorrhage (amenable to tourniquet application). This study also introduced hemorrhage from another distinct anatomic and clinically important location– from junctional areas between the torso and the extremities. Junctional vascular trauma or hemorrhage from the proximal femoral or axillobrachial vessels often is not amenable to direct pressure or application of a tourniquet and therefore poses an especially difficult problem. In the study by Kelly, 20% of deaths from hemorrhage occurred from injuries to these junctional zones. Again, in these early studies from the war, NCTH was not explicitly defined but encompassed disruption of any torso vascular structure that resulted in bleeding.

Interestingly, these figures remained unchanged when Eastridge et al, expanded this analysis to all U.S. military personnel who died of wounds between 2001 and 2009. While lethal head injury was the dominant pattern of trauma in the nonsurvivable cases, hemorrhage again accounted for 80% of potentially survivable deaths. Truncal hemorrhage accounted for 48% deaths in this cohort of these casualties. Publication of these studies provided an important characterization of battlefield injury and illustrated the high and early lethality of NCTH in those who could have otherwise survived their injuries. In parallel with postmortem studies, several clinical studies have examined the incidence of hemorrhage in specific organ systems.

In a study using the U.S. Joint Theater Trauma Registry (JTTR), White and colleagues reported the incidence of vascular injury in U.S. troops between 2002 and 2009. The authors of this study observed a specific vascular injury rate of 12% (1570 of 13,075), which was 5 times higher than that described in previous in wartime reports. Named large vessel injury accounted for 12% of the torso vascular injuries in White’s study, with iliac, aortic and subclavian vessels being the most commonly injured. In a separate study also using the JTTR, Propper et al examined wartime thoracic injury between 2002 and 2009. In this report, the authors found that thoracic injury of any type occurred in 5% of wartime casualties. In this cohort, the mean Injury Severity Score (ISS) was 15 and the crude mortality was 12%. The most common thoracic injury pattern in Propper’s study was pulmonary contusion (32%), followed by hemopneumothorax (19%).

A report by Morrison and co-workers, from a single combat support hospital in Afghanistan, analyzed 12 months of consecutive episodes of abdominal trauma. Over half (65 patients, 52.0%) required immediate laparotomy, with hemorrhage from solid organs identified in 46 patients (70.8%). There were 15 deaths (23%) in patients undergoing immediate laparotomy with a median New Injury Severity Score (NISS) of 29 and range of 1-67.

Despite the value of these studies, they do not specifically emphasize the potential lethality from vascular disruption resulting in NCTH. In this context, given the undeniable association of NCTH with early mortality in those with otherwise survivable injuries, military researchers and civilian collaborators have aggressively sought to establish a unifying definition of this pattern of vascular trauma. Table 8-1 illustrates the initial definition of NCTH, which was developed at the U.S. Army’s Institute of Surgical Research and is based on the previously mentioned anatomic categories of vascular disruption linked to either a physiologic or a procedural criterion. A procedure in this definition is defined as an emergent laparotomy, a thoracotomy, or a procedure undertaken to control bleeding from a complex pelvic injury.

Defining Noncompressible Torso Hemorrhage

These observations have resulted in a thrust within the combat casualty care research community to better define and classify locations and patterns of NCTH. Despite its obvious significance, a consensus definition of NCTH was lacking until the wars in Afghanistan and Iraq. Reports have emerged recently from the military’s Joint Trauma System (JTS) and select civilian institutions proposing a unifying classification of this injury pattern. It has been the aim of these studies to establish a cohesive definition allowing for study of the epidemiology of this problem and allowing for comparison of management strategies with the hope of mortality reduction. Until these recent reports, studies of injuries within the torso focused on specific organ injuries (e.g., a series of liver injuries), or they fell along specialty boundaries (e.g., a vascular surgeon’s approach to iliac artery repair).

The wartime perspective on NCTH works from the premise that vascular disruption with bleeding can arise from an array of anatomic sites, as follows:

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  Large axial vessels

  
  
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  Solid organ injuries

  
  
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  Pulmonary parenchymal injuries

  
  
• •
  

  Complex pelvic fractures

As such, the contemporary definition of NCTH begins with the presence of vascular disruption from one or more of four anatomic categories listed in Table 8-1 . Cardiac wounds are not included within this definition because of their high mortality.

In order to identify only patients with active hemorrhage from these anatomic categories, the definition of NCTH includes the presence of physiologic measures or operative procedures that reflect hemodynamic instability and/or the need for urgent hemorrhage control. These include hypotension or shock and the need for emergent laparotomy, thoracotomy, or a procedure to manage bleeding from a complex pelvic fracture. Without the physiologic or procedural inclusion criteria, the definition of NCTH would be prone to include injuries within the at-risk anatomic category that does not include active bleeding. The following sections will review the military and civilian experience with noncompressible torso hemorrhage and will provide an overview of surgical and resuscitative strategies.

Epidemiology of Noncompressible Torso Hemorrhage

A recent study of the U.S. JTTR presented at the American Association for the Surgery of Trauma in 2011 used the definition presented in Table 8-1 to characterize the epidemiology of NCTH in patients injured in Iraq and Afghanistan between 2002 and 2010. Using the injury pattern criteria alone, 1936 patients were identified as each having an injury putting them at risk for NCTH, which was nearly 13% of battle-related casualties. When the physiological and procedural inclusion criteria were applied to this cohort, 331 patients with a mean ISS ± standard deviation (SD) of 30 ± 13 were identified as having NCTH. The most common pattern of hemorrhage was pulmonary parenchyma (32%) followed by bleeding from a named, large vessel within the torso (20%). High-grade solid organ injury (grade IV or V liver, kidney, spleen) also constituted 20% of cases, and pelvic fracture with vascular disruption accounted for 15%. The most lethal injury pattern in this study (odds ratio: 95% CI) was injury to a named large vessel within the torso (3.42; 1.91-6.10), followed by injury to the pulmonary parenchyma (1.89; 1.08-3.33) and complex pelvic fracture with vessel disruption (0.80; 0.36-1.80).

The same authors applied this definition to British troops injured in Iraq and Afghanistan from 2001 to 2010 using the UK Trauma Registry. This analysis included patients who died before receiving treatment at a military surgical hospital (i.e., killed in action [KIA]) and thus did not apply the physiologic or procedural inclusion criteria. This report identified 234 patients with the anatomical injury profile at risk for NCTH, which was 13% of UK battle-related injuries—a number nearly identical to the incidence of this injury pattern in the U.S. JTTR. The overall case fatality rate of UK patients with NCTH was 83% compared to 25% for any battle-related injury, underscoring the significant mortality burden posed by vascular disruption of any type within the torso.

The civilian experience with NCTH carries a similar message, albeit with a different injury pattern. Specifically, vascular injury or disruption within the torso in the civilian population consists predominantly of blunt rather than penetrating or explosive mechanisms. Hemorrhage remains the leading cause of potentially preventable death in civilian settings accounting for 30% to 40% of mortality, with 33% to 56% of such deaths occurring in the prehospital phase of injury. Tien and co-workers examined 558 consecutive trauma deaths at a Canadian Level I trauma center. While the most numerous causes of death related to CNS injury, 15% were due to hemorrhage, with 16% of such deaths judged to be preventable. Delay in identifying the bleeding source was cited as the most common preventable reason, with pelvic hemorrhage being the most common source. These findings were confirmed and extended by investigators at Los Angeles County and University of Southern California Medical Center, who identified delayed pelvic hemorrhage control as the most frequent cause of preventable deaths from hemorrhage.

Clinical Management Strategies in Torso Hemorrhage Control

The aim of this section is to complement the forthcoming chapters on the definitive management of specific vessel injuries by introducing strategic surgical concepts within the context of the current literature. The surgical management of the “nontraditional” vascular injuries—pulmonary parenchymal, solid organ, and pelvic hemorrhage—is also discussed in order to provide a holistic view of torso hemorrhage control. Throughout these chapters, the fundamental tenants of vascular surgery remain: proximal control and distal control are essential when managing any suspected vascular injury.

Damage Control Surgery and Damage Control Resuscitation

Damage control surgery (DCS) is a strategy originally described in the context of exsanguinating abdominal trauma, where the completeness of operative repair is sacrificed in order to limit physiologic deterioration. This technique has been extended to include other body regions. Definitive operative repair is then completed in a staged fashion following resuscitation and warming in the intensive care unit. DCS is an extreme surgical strategy that should be selectively applied because infection, intraabdominal abscess, wound dehiscence, incisional hernia, and enterocutaneous fistulae are common with its use.

Military experience in Iraq identified a survival benefit in patients receiving a higher ratio of packed red blood cells (PRBCs) to fresh frozen plasma (FFP) and found that they had a significantly lower mortality than patients receiving the lower ratio (19% vs. 65%; p < 0.001). This finding has brought about the concept of a balanced or hemostatic resuscitation, where major trauma patients are resuscitated with a unit ratio of around 1 : 1 PRBC to FFP. This concept has evolved into a coherent strategy incorporating additional hemorrhage control adjuncts and is termed “damage control resuscitation (DCR).” Most DCR protocols incorporate techniques such as permissive hypotension, minimal use of crystalloid, aggressive warming, and novel infusible hemostatic drugs such as tranexamic acid paired with damage control surgery for early hemorrhage control.

Importantly, damage control surgery (DCS) should be considered a tool within DCR, which may be utilized in circumstances of extreme physiology or significant anatomical injury burden. The evidence thus far suggests that the adoption of DCR confers a survival advantage, and is associated with a reduction in the use of DCS techniques. However, while DCR demonstrates significant promise, it does liberally utilize precious resources exposing patients to the risks associated with blood products. Work is being undertaken on product ratios and the use of novel compounds to reduce this reliance, such as lyophilized fibrinogen and platelets.

Resuscitative Surgical Maneuvers

A proportion of patients with vascular trauma resulting in noncompressible torso hemorrhage (NCTH) have circulatory collapse, either profound hypotension or cardiac arrest. With the burden of injury resulting from the wars in Iraq and Afghanistan, the management of these patients has been extensively studied. The current civilian standard in this setting is to perform a resuscitative thoracotomy (RT) to enable release of cardiac tamponade, to enable control of a massive air leak, to obtain thoracic hemostasis, and to accomplish thoracic aortic occlusion. The latter maneuver is undoubtedly the most practiced because aortic control has several beneficial effects in hypovolemia—namely, to enhance cerebral and myocardial perfusion. While RT is typically performed for thoracic wounding, it has been explored for use in patients with a tense hemoperitoneum in physiological distress. The aim is to obtain control of the vascular inflow of the abdomen, while enhancing central pressure, before laparotomy and abdominal hemostasis. This approach is now being challenged due to the poor survival rate, although the physiological principle of aortic occlusion supporting central pressure remains.

Resuscitative techniques where proximal control is remote to the site of injury should not be used liberally, as direct vascular control, where possible, results in a lesser ischemic burden. A recent animal study that examined thoracic clamping versus aortic clamping versus direct control of an iliac arterial injury identified a significantly reduced burden of global ischemia with direct control.

Resuscitative aortic occlusion can also be achieved by use of a compliant endovascular balloon as demonstrated by the use of percutaneous devices to control inflow to abdominal aortic aneurysms during endovascular repair. This technique enables the physiological benefit to be realized without the additional burden of entering the abdomen or thorax. Such a technique was utilized in trauma as early as the Korean War and has been utilized since. It has not been used widely or been evaluated systematically. However, with recent improvements in endovascular devices and overall resuscitation strategy, there is a renewed interest in this approach that has been termed “resuscitative endovascular balloon occlusion of the aorta (REBOA).”

Recent animal work has characterized the reduced physiological burden of REBOA compared to RT. Animals in Class IV shock were allocated to aortic occlusion by a balloon or clamp via thoracotomy. The balloon group demonstrated the same improvement in mean aortic pressure as the clamp group, but with a lower lactate, base excess, and pH measurements post intervention. A different group has identified 40 minutes as the optimum time for aortic balloon occlusion in hypovolemic animals using similar end points.