Introduction

Point of Care Ultrasound (PoCUS) is the use of portable ultrasonography to answer specific, focused clinical questions at the bedside. It is an extension of both our clinical acumen and physical exam. PoCUS is commonly used in adult trauma cases as part of the focused assessment with sonography in trauma (FAST) examination. In undifferentiated and hemodynamically unstable patients, PoCUS can rapidly identify intra-abdominal free fluid which can expedite management and disposition decisions. When ascites is suspected, PoCUS may be used to confirm the diagnosis and guide further management. In recent years, the use of PoCUS has expanded to include pediatric patients as well.

 

Why Ultrasound?

PoCUS is superior to physical exam in detecting intra-abdominal free fluid. In addition, PoCUS can be performed quickly at the bedside without exposure to ionizing radiation. Physical exam alone is a poor test for the detection of peritoneal free fluid, with an overall accuracy of 58% [1]. Studies have shown that as little as 10-50cc of peritoneal free fluid can now be detected with ultrasound. In the hands of emergency doctors, volumes of 100-200 mL of fluid can be routinely detected at the bedside [2,3]. These numbers hold true for trauma patients as well. In 2007, Soyuncu et al. showed emergency physician performed ultrasound detected intraperitoneal hemorrhage with a sensitivity of 86% and specificity of 99% while physical examination reported a sensitivity of 39% and specificity of 90%, respectively [4].

The use of ultrasound in the child who has sustained trauma requires special mention. In the setting of the unstable trauma patient it is critical to identify the cause of decompensation as early as possible as it helps guide and prioritize management decisions, including further diagnostic workup and early disposition from the ER.  The focused abdominal sonography in trauma (FAST) exam is both sensitive and specific in critically ill, hypotensive pediatric trauma patients [5]. It is best used to screen for significant intra-abdominal injuries requiring emergent transfer to the operating room in the unstable patient. In the stable patient, the utility of the FAST is debated and the sensitivities range from 25-80% for the detection of all intra abdominal injuries, though it performs better in those injuries with hemoperitoneum [6]. Performing serial FAST as well as the combining findings with clinical exam and laboratory investigations can increase the sensitivity of the FAST examination [7, 8, 9]. While CT remains the gold standard screening tool for intra-abdominal injuries, the use of the FAST exam may have the ability to decrease CT use in pediatric patients.

The FAST scan can be a challenging scan to master as adequate sonographic windows may be difficult to obtain and multiple areas must be investigated under challenging conditions. Studies show the false negative rate of scans decreases with increasing physician experience. Deliberate practice is key to attaining proficiency [10].