Vascular Injury Goals

The first goal of resuscitation and the management of a patient with PVI is hemorrhage control. There are multiple types of vascular injury, which are outlined in Table 17.1. The main focus of this chapter will be extremity hemorrhage/PVI.

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  Extremity Hemorrhage/PVI, as its name suggests, is any injury to the vasculature of the extremities resulting in hemorrhage. These injuries typically affect smaller vasculature and are more likely to have a better outcome than other types of injuries (Figure 17.1).

  
  
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  Junctional Hemorrhage is defined as hemorrhage where an extremity meets the torso that precludes the effective use of a tourniquet to control bleeding.⁵ Examples of junctional hemorrhages include the groin proximal to the inguinal ligament, the buttocks, the gluteal and pelvic areas, the perineum, the axilla and shoulder girdle, and the base of the neck (Figure 17.2).

  
  
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  Non Compressible Truncal/Torso Hemorrhage is defined as trauma to torso vessels, pulmonary parenchyma, solid abdominal organs, and disruption of the bony pelvis.⁷ As the name implies, these are injuries not amenable to tourniquets, not amenable to compression, and overall have a very high mortality rate because of the rate of bleeding (Figure 17.3).

Figure 17.1 Penetrating injury to the upper arm

(from War Surgery in Afghanistan and Iraq)³,⁴

Figure 17.2 Example of junctional injury

(from War Surgery in Afghanistan and Iraq)^{3, 6}

Figure 17.3 Example of NCTH

(from War Surgery in Afghanistan and Iraq)^{3, 8}

Most vascular injuries are obvious in presentation; however, some are subtle, and attention to detail is required.⁹ Assessment for both hard and soft signs of injury is vital for injury classification (Table 17.2). This allows the clinician to determine the next best step in managing the patient. In general, patients with hard signs of vascular injury will need immediate intervention, while those with soft signs should receive diagnostic testing to better determine the type of injury. Hard signs of vascular injury are shown in Figure 17.4.

Figure 17.4 Example of a hard sign of vascular injury

(from War Surgery in Afghanistan and Iraq)^{3, 10}

Physiologic Goals

In an ideal situation, unstable patients with penetrating vascular trauma are transported immediately to the operating room. This is not always the case when caring for trauma patients, as there are many factors than can delay operative intervention (surgical consultant not in house, multiple casualties necessitating triaging, etc.). Because of these factors, it is imperative for the emergency physician to be knowledgeable of how to appropriately resuscitate a patient with active hemorrhage. While Advanced Trauma Life Support (ATLS) provides an excellent basis and systematic approach to trauma patients, there are some aspects of these algorithms that are falling out of favor and less applicable to patients with massive hemorrhage. For example, previous versions of ATLS recommended initial crystalloid resuscitation, which in both military and civilian settings has been associated with poor outcomes including multi-organ failure, death, and abdominal compartment syndrome.¹¹

Damage control resuscitation (DCR) is broadly defined as a resuscitative strategy in which hemorrhage is controlled while preventing coagulopathy.¹² Physiologic parameters of DCR are outlined in Box 17.1. The basic underlying principles of DCR include permissive hypotension, balanced component therapy, and coagulopathy prevention.^13–22 This is further explored in detail in Chapter 3.

Secondary Injuries

While there are numerous complications from penetrating vascular injury, most of these are delayed and occur after initial evaluation and repair. While these are more applicable to the inpatient team, they include limb ischemia, wound infection, and vascular graft/repair thrombosis. There are some complications, though, that the emergency physician should be aware. Most severe penetrating vascular trauma will involve large vessels, and, by the principles of anatomy, these vessels most usually run in neurovascular bundles. It is important to consider concomitant vein and nerve injury when evaluating arterial injury. Although the immediate management may not differ, the importance of performing and documenting a thorough neurovascular is important.

The documentation and monitoring of the neurovascular exam also becomes important when monitoring for compartment syndrome, which is a mismatch between the volume and contents of a muscular compartment leading to tissue ischemia and necrosis.²⁴ This can be from many different etiologies, but the basic concepts are increased pressure, decreased volume, or external compression. This pressure overcomes the venous and eventually arterial blood supply leading to extremity pulselessness, paresthesias, pallor, pain, and eventually tissue death. Although management of this condition is ultimately surgical, expeditious diagnosis and treatment is paramount to preventing complications such as contractures.

ED Evaluation and Management

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  The most important step in management is hemorrhage control. There are numerous ways to approach this goal, but the Trauma Combat Casualty Care Guidelines summarize this approach (Box 17.2).

  
  
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  Any patient presenting with life threatening injury should always be evaluated for patency of the airway, work of breathing, and perfusion status. In the best of scenarios this should take place simultaneously while hemorrhage control is being obtained.

While surgery is the definitive answer for most severe penetrating vascular injury, the first principle in the initial management should be hemorrhage control. Direct pressure over the area of bleeding is the first and most important step. After this there are numerous other modalities available for control of bleeding. Other goals of ED resuscitation are listed in Box 17.3.

When acting to control hemorrhage, one must first recognize the type of injury. For most extremity injuries with active hemorrhage, tourniquets are a cheap, readily available, and efficacious method to control bleeding. Tourniquets for the most part had fallen out of favor until their re-emergence in Operation Iraqi Freedom. Multiple studies demonstrate favorable outcomes when tourniquets have been applied in the battlefield setting.^25–27 Tourniquets have become an integral part of Trauma Combat Casualty Care (TCCC). While there are multiple facets to the TCCC guidelines, the basic premise for use is early applications of a tourniquet to a bleeding extremity as “high and tight” as possible until hemorrhage control is obtained.²⁸

Tourniquet use in civilian settings was previously limited; however, tourniquets have re-emerged as essential for civilian pre-hospital care. In addition, there are now numerous centers in the United States studying the pre-hospital use of tourniquets.²⁹ The long standing debate and controversy is whether these devices cause more harm than good.³⁰ While the injuries incurred during wartime are different than those in the civilian setting, the same principles can still be applied, with appropriate use (Box 17.2). Complications that can occur from tourniquets include compartment syndrome, neuropraxia, nerve paralysis, and limb ischemia.³¹ While most complications have been noted at greater than 2 hours, a tourniquet should not be removed if hemorrhage cannot be controlled by other means. In the civilian setting, prolonged tourniquet use should not be as much of an issue as the battlefield, where definitive care is not always immediately available.

For injuries not amendable to tourniquet placement or if a tourniquet is not available, direct pressure over the wound is the next viable option.³² Clamping and ligation may be performed by a surgeon when indicated, but the initial recommendation for ED management is to avoid these maneuvers when possible, as this may hinder future vessel repair.

Numerous hemostatic agents and dressings are on the market. These agents have been shown to be superior to standard non-hemostatic dressings in numerous studies.³³ However, a recent study that emulated severe penetrating vascular injury in areas not amendable to tourniquet placement showed standard gauze without hemostatic agent compared equally well to hemostatic agents in a swine model.³⁴ Therefore, while hemostatic agents may confer benefit to some specific types of wounds, the most important aspect of hemorrhage control is direct pressure over the area of vascular injury, regardless of dressing type.

Once hemorrhage control has been accomplished, the next goal is determining those requiring emergent intervention (Figure 17.5).

Figure 17.5 PVI Algorithm

(from War Surgery in Afghanistan and Iraq)^{3, 8, 32}

If the patient has soft signs of vascular injury, the next best step is to perform an Injured Extremity Index (IEI). The IEI is similar to an ankle brachial index, with the exception that this is used to compare opposite extremities, as opposed to upper and lower. The first step is to apply a manual blood pressure cuff, inflate the cuff until cessation of pulses by Doppler, and then determine the pressure at which the arterial Doppler signal returns in the injured extremity as the cuff is deflated, which is the numerator in the equation. Next, the cuff and Doppler are moved to the uninjured extremity, ideally an uninjured upper extremity, and again the pressure at which the arterial Doppler signal returns as the cuff is deflated is recorded as the denominator in the ratio. An IEI >0.90 is normal and has high sensitivity for excluding major extremity vascular injury.¹⁰ The negative predictive value of an IEI >0.90 approximates 96%.¹¹ Due to IEI’s ease of use, rapidity, and noninvasiveness, it is an ideal test that emergency physicians should use in the care of patients with suspected vascular injury.

CT angiography remains the gold standard for the diagnosis of vascular injuries because of its accuracy, cost, and rapidity.^{35, 36}

Duplex ultrasound has been evaluated in the diagnosis of this condition but does not have high enough sensitivity to exclude these injuries.^{37, 38} In formally performed ultrasounds that are interpreted/performed by a vascular technologist or vascular surgeon, a finding of arterial injury by ultrasound may obviate the need for CTA in the correct circumstance. While this test may be useful to rule in arterial injury, it should never be used to exclude arterial injury.³⁹ To the author’s knowledge, there have been no randomized studies on the use of Point of Care Ultrasound (POCUS) for the evaluation of penetrating vascular injuries. Therefore, POCUS can only be recommended as an adjunct in the evaluation of these patients.

Low Risk Penetrating Extremity Injury Management and Disposition

If after evaluation the patient has been found to be at low risk for penetrating extremity injury (Box 17.4), it is reasonable to observe the patent in the ED with serial examinations and IEI measurements. If the patient’s symptoms and exam are reassuring, IEI remains >0.9, and the patient does not develop compartment syndrome, then wound irrigation, analgesia, and discharge with follow up with a surgeon is a reasonable option. This should be performed in accordance with predetermined policies at the institution or in consultation with a trauma surgeon.

Antibiotic therapy is not recommended for routine low velocity and uncomplicated gunshot wounds/penetrating wounds of the extremities.⁴⁰ There are some special situations which antibiotic therapy may be warranted; however, these fall out of the low risk category and include high velocity injuries, open fractures, heavy wound contamination, joint involvement, and hand injuries.⁴¹ The most important aspect in the care of low risk injuries is to provide detailed discharge instructions and strict return precautions for complications of these injuries. In particular, compartment syndrome, sudden swelling, worsening bleeding or repeated soaking of dressings, fevers, and a cold distal extremity should be addressed with the patient.

Surgical Indications

Any patient not falling into the low risk category requires more definitive evaluation. Patients with hard signs of vascular injury stable for transport should be taken immediately to the OR. An unstable patient requires resuscitation until stable for transport and definitive repair.

Patients with soft or non-specific signs of vascular injury should undergo an IEI vs. CTA of the affected extremity based on availability. If there are signs of arterial disruption on CTA, or if the IEI is <0.9, then the patient should receive operative consultation and management for presumed vascular injury. An IEI <0.9 is often evaluated further with CTA. In patients who have a normal physical exam (no hard or soft signs) and a normal IEI, the likelihood of arterial injury is exceedingly low, and further testing does not need to be performed. Physical exam or IEI used in isolation does not have high enough sensitivity to exclude a vascular injury.³⁹

Pitfalls in ED Evaluation and Management

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  Not suspecting vascular injury with penetrating injury. Many of these may have no decrease in pulse, patients may be asymptomatic, or have subtle exam findings.

  
  
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  Overzealous administration of fluids. Hemorrhage requires replacement of what is lost: RBCs, platelets, and clotting factors.

  
  
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  Not aggressively controlling hemorrhage (failure to apply tourniquet).

  
  
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  Not consulting the appropriate service when there is uncertainty about the injury.