Chapter 11 Intensive Care Unit

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SECTION 1 • Techniques and Methods in Critical Care

and hemothorax) are evaluated. The liver, spleen, and partially filled bladder provide the necessary sonographic windows. The abdominal sequence leads with the right flank and gutter before the left flank and gutter exams because blood originating from both splenic and hepatic trauma must first pass through the Morison pouch on before collect- ing in the more dependent pelvic cavity. As in other applications ACUS, the FAST protocol should be considered to provide very useful but often not sufficiently definitive information to preclude radio- logic studies or even exploratory surgery. Some serious injuries are seldom visualized confidently by US (e.g., aortic and diaphragm tears, pancreatic lesions, bowel perforations, mesenteric trauma, and injuries that do not produce free fluid in amounts >250 mL). Fluid acutely collected in the pelvis may be either urine or blood. Although important penetrating injuries may go unsuspected with the initial evaluation, overall sensi- tivity of FAST in these and for all abdominal injuries may improve by performing serial US examinations. INTERVENTIONAL RADIOLOGY FOR CRITICAL CARE Interventional radiology is another imaging disci- pline whose indications have dramatically increased for the past decade. Dynamic imaging capabilities

such as C-arm fluoroscopy and angiography com- bined with elegant 3-dimensional reconstructions, precise localization, and an ever-expanding arsenal of catheter-based devices and stents now enable per- formance of high-value, low-morbidity procedures. These include otherwise routine cannulation proce- dures that cannot be attempted successfully at the bedside as well as many sophisticated therapeutic procedures that stabilize hemorrhage, relieve isch- emia, and obviate the need for high-risk operative intervention. Broadly speaking, the major purposes are usefully classified as vascular and nonvascular in nature. The vascular indications include trouble- some bleeding in need of control by embolization of the appropriate arterial source and the extraction of thrombi and placement or manipulation of intravas- cular catheters. Endovascular stent placements may be lifesaving (e.g., aortic dissection and transjugular intrahepatic portosystemic shunt [TIPS] procedures for portal decompression [Fig. 11-25]). Nonvascular indications for IR generally involve drainage of an infected pocket, placement of stents, feeding tubes, and super pubic catheters. The IR service should be engaged early in the decision-making process, particularly when surgical intervention is a con- templated alternative option. Although the range of problems and potential solutions is already vast and continually expanding, certain of these deserve mention here.

Catheter

Hepatic vein

Stent in place

Left lobe of the liver

Right lobe of the liver

Guidewire

Portal vein

Splenic vein

Superior mesenteric vein

FIGURE 11-25. Left: Schematic depiction of catheter-mediated TIPS stenting procedure for portal venous decompression. Right: TIPS stent inserted via catheter (subtraction fluoroscopic image with contrast).