The intensivist must often consider the abdomen of the critically ill patient as a source for concern. Whether in the medical, surgical, cardiac, neurological, or transplant intensive care unit (ICU) patient, the source of bleeding, fever, pain, jaundice, or elevated white blood cell (WBC) count is often found in the peritoneal cavity or retroperitoneum. Focused ultrasonographic assessment can often help to identify the problem and assist with therapy.
The American Institute of Ultrasound in Medicine (AIUM) delineates eleven indications for an abdominal ultrasound examination (Table 23.1).1 All but indications number “6” and “7” may be applicable to the ICU patient. Acute appendicitis, cholecystitis, mesenteric ischemia or an abscess may all cause abdominal pain and are potentially detectable by ultrasound. Jaundice may be due to acalculous cholecystitis whose sonographic features are discussed below. A mass caused by a hernia with bowel intrusion into a sac may be appreciated by ultrasound. Further, the cause of an elevated white blood cell count or the presence of fascial dehiscence may also be readily apparent by ultrasound. Trauma patients with solid visceral organ damage (liver, spleen, or kidney) can be followed for the continued wisdom (or lack thereof) of nonoperative management. Renal and hepatic transplant patients can undergo ultrasound screening for evaluation of the perfusion of their transplanted organs, as can those with new onset failure of their native ones. Finally, the presence and nature of peritoneal fluid can be assessed by ultrasound to guide drainage.
Table 23.1. AIUM Indications for Abdominal Ultrasonography |Favorite Table|Download (.pdf)
Table 23.1. AIUM Indications for Abdominal Ultrasonography
Abdominal, flank, and/or back pain
Signs/symptoms referred from abdominal organs, such as jaundice
Palpable abnormalities such as a mass
Abnormal lab value suggestive of abdominal pathology
Follow-up of known or suspected abdominal pathology
Search for metastatic disease or occult primary neoplasm
Evaluation of suspected congential abnormalities
Pre- and posttransplantation evaluation
Planning and guidance for an invasive procedure
Search for the presence of free or loculated peritoneal and/or retroperitoneal fluid
Of course, the concept of a focused ultrasound exam performed by nonradiologists to address a specific question originated with a limited abdominal examination performed by trauma surgeons, the so-called focused assessment with sonography for trauma (FAST) protocol.2–4 Although the acronym is now known as the “focused assessment with sonography for trauma,” in recognition of the components of the exam that assess the thorax, the “A” in FAST originally stood for “abdomen.”5 We believe that all ICU patients undergoing abdominal ultrasonographic examination should be studied with a variant of the FAST, that is, a search for fluid. The amount, location, and loculation of the fluid should be assayed and compared to prior studies, if any. Additional focused components of the exam should be added as needed (Table 23.2). Indeed, the initial description ...