**4. Diagnosis**

*Trauma and Emergency Surgery - The Role of Damage Control Surgery*

mal level of injury and number of liver segments affected.

tion" topic ahead [5].

be up to 20% [6].

**3. Classification**

Most hepatic injuries are minor and can be graded using the American Association for the Surgery of Trauma Hepatic Injury Scale as described under the "classifica-

The right lobe of the liver, being the largest portion of the liver parenchyma, constitutes the region most affected during abdominal injury. It is known that it occurs more frequently in males and in young individuals, in the first four decades of life, in the majority of cases. Associated factors include risky behavior, such as alcohol and drug consumption, and more exposure to accidents. The mortality of patients with liver trauma ranges from 14.9–20%. When associated with shotgun lesions, the severity of the injury tends to be higher; therefore, the mortality could

The severity of liver injuries is classified according to the American Association for the Surgery of Trauma (AAST) grading scale. This scale is based on parenchy-

To understand the classification of liver trauma, it is essential to master the anatomy of the liver. The division of the liver by the Couinaud segments occurs through the branching of the portal triad, composed of the branch of the portal vein, the hepatic artery, and the bile duct. The ramifications of these vessels cause the portal blood to be mixed with the blood in the hepatic artery in the portal spaces, which drains into the centrilobular vein, subsequently into the sublobular veins, and through the two hepatic veins, which end in the inferior vena cava. **Table 1** shows the classification of liver trauma according to the AAST.

The degree of liver injury and hemodynamic instability are important determinants in the mortality rates of patients with liver trauma as well as to determine the type of treatment to be instituted [2]. The concomitance of intra-abdominal injuries with liver trauma is common in penetrating trauma, and it is also a relevant factor

**54**

**Table 1.**

*Classification of hepatic trauma (AAST).*

Currently, the most useful complementary exams in the diagnosis of liver trauma are abdominal ultrasound and computed tomography (CT) with intravenous contrast. Abdominal ultrasound is the initial image exam, with a sensitivity of 82–88% and specificity of 99%, to detect intra-abdominal injuries, although it must be taken into account that the accuracy depends on the examiner's experience [8]. Computed tomography is the most sensitive and specific technique for determining the extent and severity of liver trauma and is the imaging test that provides us with more information on polytrauma patients, since it offers an excellent view of the skull, chest, abdomen and pelvis, bone structures, viscera, and soft tissues. The arrival of helical technology has improved the resolution, reduced the duration of the exam, and allowed the three-dimensional reconstruction of the images, which is very useful if there is vascular involvement.

Diagnosis by peritoneal lavage (LPD), with the advent of new imaging techniques, has fewer indications. Although it has an accuracy of 98% to detect intraperitoneal blood, it lacks specificity of the injured organ, which causes many unnecessary laparotomies [8].

In patients with hemodynamic instability, the Focused Assessment with Sonography for Trauma (FAST) is the exam of choice due to its sensibility to detect free fluid in the abdomen, and it can be done faster than CT as an initial exam. **Figures 1, 2**, and **3** show some possible changes in abdominal CT in patients with liver trauma.

Some more recent studies have shown the role of two-dimensional and threedimensional [15] ultrasonography (US) in the trauma of massive viscera, such as the liver. There is evidence that the regular US is not capable of having high

#### **Figure 1.**

*Hemorrhagic hepatic lacerations (A) in the right hepatic lobe and (B) close to the hilum. Hypodense areas of linear morphology that come into contact with the capsule (arrows). They associate free liquid (asterisks).*

#### **Figure 2.**

*Extension to the inferior vena cava. There is a large hepatic termination with extension to the inferior vena cava (arrow), which appears to be free of perihepatic primary fluid and active for bleeding (asterisk).*

#### **Figure 3.**

*Active bleeding. Active contrast leakage (arrow) is observed in a patient with severe hepatic trauma. Associated perihepatic fluid (hemoperitoneum). Splenic infarction (\*).*

sensitivity to detect active bleeding in a solid abdominal organ. In recent years, US using contrast agents could greatly improve the detection of bleeding. Recently, contrast US has mainly depended on two-dimensional ultrasound (2DUS). With the development of imaging technology, three-dimensional static ultrasound (3DSUS) and real-time three-dimensional ultrasound (RT3DUS) can provide more accurate images and additional information in some assessments of abdominal disease. Thus, there are new technologies and possibilities for measuring the degree of hepatic impairment, but these are not always available, and sometimes just the physical examination is possible as a diagnostic tool [8].
