Chapter 11 Intensive Care Unit

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CHAPTER 11 • Intensive Care Unit Imaging

Vascular Catheter Placement Bedside US has become an indispensible aid in plac- ing central catheters and arterial lines, both speed- ing the process and reducing hazard and discomfort. During the procedure and once placed, the catheter usually can usually be distinguished from the tar- geted vessel, confirming successful vascular entry or alerting the clinician to malpositioning. Immediate postprocedural thoracic US following jugular and subclavian punctures may alleviate concerns of pro- cedure-related pneumothorax if the signs of “lung sliding” and clear A or B lines signs are detected. US has become an integral adjunct to PICC place- ment from the brachial sites in difficult cases (e.g., upper extremity edema). Provider-performed US of the upper extremity may be serially conducted when concern arises regarding the possible development of upper extremity thrombosis. Confirmation of clot presence or absence, however, should usually be sought by formal US consultative studies. Abdominopelvic Ultrasound and FAST Scanning Apart from diagnosis and treatment of ascites, US of the abdomen and pelvis has proven its value in the emergency department and ICU for evaluations of sepsis of indeterminate source, acute undiffer- entiated abdominal pain, and suspected viscus or abdominal aneurysm rupture. Questions regarding gallstone, cholecystitis, urinary tract obstruction,

soft tissue infections, and free fluid or air collec- tions may first be noninvasively approached using this methodology. Although gas detected in the biliary tree may appear after ERCP or after remote biliary surgery, its detection in the setting of abdomi- nal sepsis often suggests life-threatening infection. Emergency abdominal US in adults with abdomi- nal trauma (focused assessment with sonography for trauma [FAST]) is a widely used management- directing US survey whose results are more reliable after presentations for blunt rather than penetrat- ing trauma (Fig. 11-24). The main goal is to detect newly developed pericardial, intrathoracic, or intra- peritoneal free fluid. Acknowledged limitations are that FAST is less sensitive for pelvic bleeding, does not interrogate the retroperitoneum, and can- not reliably differentiate the nature of what caused the pathologic fluid collection (blood, urine ascites). Points of sonographic access (windows) are used to evaluate the pericardial, peritoneal, and pleural cavi- ties. Unless a pointed indication interrupts the order, the examination sequence reflects the severity of potential life-threatening risks. The heart is assessed for the presence of cardiac tamponade, global wall motion abnormalities and other evidence of injury, and the adequacy of right ventricular filling. After the heart and pericardium, the right flank (hepatorenal view or “Morison pouch”), left flank (perisplenic view), pelvis, and thorax (pneumothorax

Thoracic

LUQ

RUQ

SubX

FIGURE 11-24.  The acoustic ultrasonic windows used in the FAST algorithm.

Pelvis