**1.2 Focused assessment with sonography in trauma (FAST)**

Advanced trauma life support (ATLS) guidelines have incorporated bedside sonography by non-radiologists in the evaluation of trauma patients. It is now standard of care to perform extended focused assessment with sonography in trauma (eFAST) in all cases as part of the primary survey and its adjuncts [5, 6]. eFAST serves to locate any obvious evidence of bleeding in the potential spaces of the abdominal and thorax. It can also help detect pneumothorax (**Table 2**). The abdomen is scanned in four areas (or views) – subxiphoid, right hypochondrium, left hypochondrium, and suprapubic (**Figure 3**). Both pleural cavities just above the diaphragm and pleural


**Table 2.** *eFAST examination.*

#### **Figure 3.**

*FAST examination views – (from left to right) subxiphoid, right upper quadrant, left upper quadrant and suprapubic [7].*

line movement on each side are also checked. FAST has even been utilized to grade the amount of intraperitoneal hemorrhage and help decide the need for laparotomy [8, 9]. Apt use of FAST has been shown to reduce time to intervention, the need for computed tomography (CT) scans, and reduce hospital stay as well as costs [10–12].

#### **1.3 Beyond eFAST**

With the advent of bedside ultrasonography, POCUS has become revolutionary in patient care. Its use in trauma settings no longer has to be limited to eFAST. Rather, this gadget can be handy in detecting several injuries within the abdomen - solid organ, hollow viscus, and even blood vessels. Timing of ultrasonography is critical so as to ensure that performing POCUS does not hinder or delay patient care. In any unstable patient with a suspected abdominal injury, the first objective is stabilization. This can include any and all measures, such as securing airway, chest drain placement, fluid resuscitation, blood transfusion, splinting, and suturing. These lifesaving interventions take time, which provides the window to examine the abdomen by POCUS simultaneously without causing undue delay. As per ATLS guidelines, unstable patients who do not respond to resuscitation require transfer to the operating room (OR). POCUS-assisted identification of injuries at the bedside would guide the operating surgeons when exploratory laparotomy is underway.

In stable patients, the timing of POCUS is more complex. Patients with suspected abdominal trauma who are hemodynamically stable may be evaluated with contrastenhanced computed tomography (CT) scans. POCUS is useful in those cases where CT scans are deferred, such as in pregnancy, intravenous contrast allergy, centers without CT capacity, and those who refuse or are uncooperative with the scan. In penetrating trauma, POCUS can be used in stable patients without the urgent need for operative intervention.

In this chapter, we will explore POCUS in abdominal trauma, which can be performed by even trained non-radiologists at the bedside.
