Chapter 81

• Alterations in gastrointestinal motility occur commonly in critically ill patients.
• The small intestine is the site of obstruction in 90% of cases of mechanical bowel obstruction. Pelvic adhesions are the most common cause. Thirty percent of cases require surgery.
• Intestinal pseudo-obstruction (nonmechanical bowel obstruction) may present with clinical symptoms that are similar to mechanical obstruction. Treatment includes nasogastric suction, rehydration, and correction of causative factors.
• Ogilvie's syndrome (colonic pseudo-obstruction) is characterized by abdominal distension and marked dilation of the cecum and right colon on abdominal x-rays. Treatment with colonoscopic decompression of the right colon is successful in about 60% of patients. Intravenous neostigmine is also effective.
• The incidence of diarrhea in the critically ill is greater than 40% and is up to 60% in patients receiving enteral feedings.
• Clostridium difficile infections are generally acquired in the hospital in patients receiving broad-spectrum antibiotics. Measurement of C. difficile toxin A or B in the stool by rapid enzyme-linked immunosorbent assay (ELISA) is the most practical method for diagnosis. Treatment consists of metronidazole or vancomycin for 7 to 14 days.
• Hyperbilirubinemia is frequently seen in patients with sepsis; cytokines along with bacterial endotoxins impair transport of bile acids at the sinusoidal and canalicular membranes, resulting in cholestasis.
• The etiology of total parenteral nutrition (TPN)-associated liver dysfunction appears to be multifactorial. The diagnosis is often made after the exclusion of other causes such as the concurrent use of potentially hepatotoxic medications, biliary obstruction, infections, and underlying intrinsic liver disease.
• Critically ill patients have multiple risk factors that predispose to acalculous cholecystitis. Patients often present atypically; unexplained fever and evidence of occult infection may frequently be the only manifestations. Ultrasonography alone is of limited value in diagnosis.
• Strong clinical suspicion and early recognition of acalculous cholecystitis are essential. Because of delays in diagnosis, more than 40% of patients develop complicated disease with gangrene, abscess, or perforation of the gallbladder.

Gastrointestinal (GI) and hepatic dysfunction are common in the critically ill patient, particularly in the setting of multiple organ system failure (MOSF) and the systemic inflammatory response syndrome (SIRS). Many factors are responsible for the pathophysiologic derangements of the GI tract and liver in critically ill patients. Disordered function may be directly related to the precipitating illness of the patient, which can lead to additive morbidity, thus perpetuating a vicious cycle. Management of disordered GI and hepatic function often necessitates aggressive and sometimes invasive diagnostic and therapeutic maneuvers, placing critically ill patients at risk for iatrogenic complications. These conditions may create vexing problems in the ongoing care of patients in the intensive care unit. It is therefore imperative for the clinician to develop a thorough understanding of the pathophysiology of GI and hepatic dysfunction in the critical care patient. This knowledge will permit identification of these conditions and allow for management decisions that are appropriate and timely.

In this chapter, we review the physiology of intestinal motility, and the pathophysiology and clinical features of intestinal obstruction and ...

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