Abdominal vascular injury

Blunt trauma

Rapid deceleration in motor vehicle crashes may cause avulsion of small branches from major abdominal vessels with subsequent hemorrhage or intimal tears with secondary thrombosis. Crush injuries to the abdomen, such as by a lap seat belt, may cause secondary thrombosis of an overlying vessel, also. Direct blows can completely disrupt vessels such as the superior mesenteric artery or vein at the base of the mesentery, leading to massive intraperitoneal hemorrhage, or even partially disrupt the infrarenal abdominal aorta, leading to the formation of a traumatic false aneurysm.

Penetrating trauma

In contrast, penetrating injuries create the same kinds of abdominal vascular injuries that are seen in the vessels of the extremities. These include blast effects with intimal flaps and secondary thrombosis, lateral wall defects with hemorrhage or pulsatile hematomas, and complete transection with either free bleeding or thrombosis. On rare occasions, a penetrating injury may produce an arteriovenous fistula, most commonly involving the portal vein and hepatic artery, renal vessels, or iliac vessels. In addition, iatrogenic injuries remain a persistent problem in many centers.

History and physical examination

As previously mentioned, an abdominal vascular injury may present with free intraperitoneal hemorrhage, a contained hematoma, thrombosis of the vessel, or some combination of these. Therefore, the presenting signs and symptoms are variable based on both the involved vessel and the presence or absence of active hemorrhage. Active intraperitoneal hemorrhage from a major abdominal artery will generally lead to unrelenting hemorrhagic shock, with the patient described as a “nonresponder” in the Advanced Trauma Life Support course. Conversely, patients with a retroperitoneal, mesenteric, or portal contained hematoma, especially with a venous injury, may be remarkably stable or present as a transient responder, and only decompensate once the hematoma is opened in the operating room. Finally, patients with blunt thrombosis of a major vascular structure will generally be hemodynamically normal, but will often complain of severe pain or will have a pulse deficit in a lower extremity.

Imaging

In both stable and unstable patients, a rapid surgeon-performed focused assessment for the sonographic evaluation of trauma patient is useful in determining the presence of intra-abdominal, intrapleural, or intrapericardial hemorrhage. In a stable patient with an abdominal gunshot wound, a routine plain film of the abdomen is of diagnostic value so that the track of the missile can be predicted from markers placed over the wounds or from the position of a retained missile.

Preoperative abdominal aortography should not be routinely performed to document intra-abdominal vascular injuries after penetrating wounds. Indeed, most patients with such wounds are not stable enough to undergo the manipulation required for appropriate studies of large vessels in an angiographic suite. In patients with blunt trauma, CT aortography is used to diagnose and treat deep pelvic arterial bleeding associated with fractures and to diagnose unusual injuries such as the previously mentioned intimal tears with thrombosis in the infrarenal aorta, the renal artery, or the iliac artery. An occasional hemodynamically stable patient with a limited abdominal vascular injury is a candidate for endovascular therapy (see later).

As the technology of CT scanning has advanced, many surgeons and radiologists are comfortable making therapeutic decisions based on data acquired from multiplanar scanning and formal CT angiography. Extensive literature exists on the diagnosis of traumatic thoracic aortic disruption with contrast-enhanced CT and several studies have shown acceptable accuracy of CT angiography in extremity trauma. Data on the use of CT angiography as a method of diagnosis of abdominal vascular injuries continue to document a sensitivity > 95%.

Damage control resuscitation and massive transfusion

In the last 15 years, based mostly on the military experiences in Iraq and Afghanistan, there has been a dramatic change in the resuscitation philosophy for critically injured patients in civilian trauma centers. The military resuscitation philosophy of “damage control resuscitation” is seen as an extension of the concepts of “damage control surgery,” a term coined in 1993 by Rotondo et al. In most civilian centers, where fresh whole blood is unavailable, the central tenet of damage control resuscitation is the early and aggressive use of blood components (fresh frozen plasma and platelets) in high, fixed ratios to packed red blood cells. In most centers, this practice requires the support of the blood bank and a highly organized massive transfusion protocol. Indeed, there are now multiple published series using institution-specific massive transfusion protocols with significant improvements in patient outcome. As many patients with abdominal vascular injuries will require massive transfusion, the treating surgeon should be familiar with the design and implementation of any massive transfusion protocol that exists in his or her institution.

With control of hemorrhage or the onset of a coagulopathy in the operating room, further transfusion of blood and components is guided by thromboelastography or rotational thromboelastometry.

Operative preparations

In the operating room, the entire trunk from the chin to the knees is prepared and draped in the usual manner. Maneuvers to prevent hypothermia should include the following: warming the operating room; covering the patient’s head; covering the upper and lower extremities with a heating unit; using a heating cascade on the anesthesia machine; infusing blood components and crystalloid solutions through a warming device; and irrigating open body cavities (thorax/pericardial sac/abdomen) during the operation.

A midline abdominal incision is made, and all clots and free blood are manually evacuated or removed with suction. A rapid inspection is performed to visualize contained hematomas or areas of hemorrhage. If active hemorrhage from a major intra-abdominal artery is encountered, a variety of techniques from simple digital pressure to formal proximal and distal control are available. Venous injuries may be managed very effectively with application of a Satinsky clamp or a series of Judd-Allis clamps applied to the edges of the perforation without the need for formal proximal and distal control. Once hemorrhage from the vascular injury is temporarily controlled in patients with penetrating wounds, it may be worthwhile to temporarily control as many gastrointestinal perforations as possible with Allis, Babcock, or vascular clamps or a stapler to avoid further contamination of the abdomen during the period of vascular repair. Once this is accomplished, the abdomen is irrigated and the vascular repair is performed followed by coverage with soft tissue.

Conversely, if the patient has a contained retroperitoneal hematoma at the time of laparotomy, the surgeon occasionally has time to first perform necessary gastrointestinal repairs in the free peritoneal cavity, change gloves, and irrigate prior to opening the retroperitoneum or mesentery to expose the underlying abdominal vascular injury.

Both the size of the vessels and their locations in the retroperitoneum, mesentery, and porta hepatis make the operative management of abdominal vascular injuries a difficult task. Once exposure has been obtained, however, the actual vascular repair is more straightforward. This is because the major abdominal arteries in young, healthy patients are free of atherosclerotic disease, although they may be vasoconstricted or relatively small (e.g., renal artery).

As previously described, the retroperitoneum may be divided into zones and each zone may be exposed by one or more operative maneuvers. Once the abdominal vascular injury is exposed, the magnitude of injury is best described using the Organ Injury Scale of the American Association for the Surgery of Trauma ( Table 2 ). The appropriate maneuvers are summarized both in Table 3 and in the algorithm shown in Figure 9 .